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  • 301.
    Benosman, Mourad
    et al.
    Abou Bekr Belkaid university, Tlemcen, Algeria.
    Salerud, Göran
    Linköpings universitet, Institutionen för medicinsk teknik, Biomedicinsk instrumentteknik. Linköpings universitet, Tekniska högskolan.
    Bereksi-reguig, Fethi
    Abou Bekr Belkaid university, Tlemcen, Algeria.
    Measuring muscle activity with ECG electrodes to distinguish physical activity from mental stress2012Konferansepaper (Annet vitenskapelig)
  • 302.
    Benosman, Mourad-M
    et al.
    Biomedical Engineering Department, Tlemcen University, Algeria.
    Bereksi-Reguig, Fethi
    Biomedical Engineering Department, Tlemcen University, Algeria.
    Salerud, Göran
    Linköpings universitet, Institutionen för medicinsk teknik. Linköpings universitet, Tekniska fakulteten.
    Strong Real-Time QRS Complex Detection2017Inngår i: Journal of Mechanics in Medicine and Biology, ISSN 0219-5194, Vol. 17, nr 8Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Heart rate variability (HRV) analysis is used as a marker of autonomic nervous system activity which may be related to mental and/or physical activity. HRV features can be extracted by detecting QRS complexes from an electrocardiogram (ECG) signal. The difficulties in QRS complex detection are due to the artifacts and noises that may appear in the ECG signal when subjects are performing their daily life activities such as exercise, posture changes, climbing stairs, walking, running, etc. This study describes a strong computation method for real-time QRS complex detection. The detection is improved by the prediction of the position of R" role="presentation" style="display: inline; line-height: normal; font-size: 11px; word-wrap: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; border: 0px; padding: 0px; margin: 0px; font-family: verdana, arial, helvetica, clean, sans-serif; background-color: rgb(223, 228, 231); position: relative;">RR waves by the estimation of the RR intervals lengths. The estimation is done by computing the intensity of the electromyogram noises that appear in the ECG signals and known here in this paper as ECG Trunk Muscles Signals Amplitude (ECG-TMSA). The heart rate (HR) and ECG-TMSA increases with the movement of the subject. We use this property to estimate the lengths of the RR intervals. The method was tested using famous databases, and also with signals acquired when an experiment with 17 subjects from our laboratory. The obtained results using ECG signals from the MIT-Noise Stress Test Database show a QRS complex detection error rate (ER) of 9.06%, a sensitivity of 95.18% and a positive prediction of 95.23%. This method was also tested against MIT-BIH Arrhythmia Database, the result are 99.68% of sensitivity and 99.89% of positive predictivity, with ER of 0.40%. When applied to the signals obtained from the 17 subjects, the algorithm gave an interesting result of 0.00025% as ER, 99.97% as sensitivity and 99.99% as positive predictivity.

  • 303. Benítez, G. E. F.
    et al.
    Parra, V.
    Huerta, M.
    Marzinotto, Alejandro
    KTH, Skolan för datavetenskap och kommunikation (CSC), Datorseende och robotik, CVAP. Simon Bolivar University, Venezuela.
    Clotet, R.
    González, R.
    Moreno, A.
    Pinto, K.
    Rivas, D.
    Alvizu, R.
    Sanchez, L. E.
    Smartphone application for quantitative measurement of Parkinson tremors2015Inngår i: IFMBE Proceedings, Springer, 2015, s. 785-788Konferansepaper (Fagfellevurdert)
    Abstract [en]

    One of the most common concerns in the atten-tion of patients with Parkinson's disease is an objectively eval-uation of the illness progress and the efficacy of treatments, in terms of the intensity and frequency of tremors. This symptom is produced by gradual degradation of the pigmented neurons located at the substantia nigra in the brain, in order to detect such movement levels. This paper proposes a Smartphone application for a quantitative detection, measurement and analysis of the Parkinson's tremor, due to the global use of Smartphones and the affordable cost of some Android plat-form devices. The subjects of this working project are those people who suffer from Parkinson's disease, who could down-load the application to their mobile phone in order to measure quantitatively the intensity and duration of their tremors, in any place, to send reports by email or to record them for a later use. The application enables the remote monitoring of the patients.

  • 304.
    Bergelin, Victor
    Linköpings universitet, Matematiska institutionen. Linköpings universitet, Tekniska fakulteten.
    Human Activity Recognition and Behavioral Prediction using Wearable Sensors and Deep Learning2017Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    When moving into a more connected world together with machines, a mutual understanding will be very important. With the increased availability in wear- able sensors, a better understanding of human needs is suggested. The Dart- mouth Research study at the Psychiatric Research Center has examined the viability of detecting and further on predicting human behaviour and complex tasks. The field of smoking detection was challenged by using the Q-sensor by Affectiva as a prototype. Further more, this study implemented a framework for future research on the basis for developing a low cost, connected, device with Thayer Engineering School at Dartmouth College. With 3 days of data from 10 subjects smoking sessions was detected with just under 90% accuracy using the Conditional Random Field algorithm. However, predicting smoking with Electrodermal Momentary Assessment (EMA) remains an unanswered ques- tion. Hopefully a tool has been provided as a platform for better understanding of habits and behaviour. 

  • 305.
    Berggren, Karl
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Medicinsk bildfysik. Philips Healthcare, Sweden.
    Danielsson, Mats
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Medicinsk bildfysik.
    Fredenberg, Erik
    Philips Healthcare, Sweden.
    Rayleigh imaging in spectral mammography2016Inngår i: MEDICAL IMAGING 2016: PHYSICS OF MEDICAL IMAGING, 2016, artikkel-id 97830AKonferansepaper (Fagfellevurdert)
    Abstract [en]

    Spectral imaging is the acquisition of multiple images of an object at different energy spectra. In mammography, dual-energy imaging (spectral imaging with two energy levels) has been investigated for several applications, in particular material decomposition, which allows for quantitative analysis of breast composition and quantitative contrast-enhanced imaging. Material decomposition with dual-energy imaging is based on the assumption that there are two dominant photon interaction effects that determine linear attenuation: the photoelectric effect and Compton scattering. This assumption limits the number of basis materials, i.e. the number of materials that are possible to differentiate between, to two. However, Rayleigh scattering may account for more than 10% of the linear attenuation in the mammography energy range. In this work, we show that a modified version of a scanning multi-slit spectral photon-counting mammography system is able to acquire three images at different spectra and can be used for triple-energy imaging. We further show that triple-energy imaging in combination with the efficient scatter rejection of the system enables measurement of Rayleigh scattering, which adds an additional energy dependency to the linear attenuation and enables material decomposition with three basis materials. Three available basis materials have the potential to improve virtually all applications of spectral imaging.

  • 306.
    Bergholm, Fredrik
    et al.
    KTH, Skolan för teknik och hälsa (STH), Medicinsk teknik.
    Hamid Muhammed, Hamed
    KTH, Skolan för teknik och hälsa (STH), Medicinsk teknik.
    Larsolle, A.
    Acquiring instantaneous multispectral imagery using a single image sensor with multiple filter mosaic2007Konferansepaper (Annet vitenskapelig)
  • 307.
    Bergkvist, Maja
    et al.
    KTH, Skolan för teknik och hälsa (STH).
    Mazaheri, Ava
    KTH, Skolan för teknik och hälsa (STH).
    Sjukhusövergripande datalager för vitalparametrar: Sammanställning av regelverk och riktlinjer2015Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [sv]

    I samband med uppbyggnaden av Nya Karolinska Solna designas ett nytt sjukhusövergripande datalager för vitalparametrar, med arbetsnamnet T5, där insamlad data ska följa patienten genom hela sjukhusvistelsen.

    Inför upphandlingen av systemet behövs en genomgång av vilka standarder, regelverk samt riktlinjer som gäller vid framställning och drift av T5. Genom djupgående litteraturstudier och intervjuer med personer insatta i områden som anses relevanta för projektet, levereras som slutprodukt en rekommendation om hur regelverken och standarderna kan tänkas appliceras på systemet.

    Projektets resultat visar att om det data som hanteras i T5 är tänkt att användas i medicinskt syfte enligt Lagen om medicintekniska produkter, så är systemet en medicinteknisk produkt. Vidare bör systemet klassificeras som riskklass I, förutsatt att informationen i T5 inte ska användas för patientövervakning i realtid.

  • 308.
    Berglund, Anders
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi.
    Branting-Ekenbäck, C
    Ohlson, M
    En översikt över chairside CAD/CAM-system i Sverige. Garanteras patientsäkerheten genom CE-märkningen av utrustning och material?2013Rapport (Annet vitenskapelig)
    Abstract [sv]

    Inom odontologin har Computer-Aided Design/Computer-Aided Manufacturing (CAD/CAM) blivit allt vanligare, främst på tandtekniska laboratorier, men tekniken blir också vanligare på tandläkarklinikerna, s.k. chairside CAD/CAM. Chairside CAD/CAM innebär att tandläkaren efter preparationen av en tand framställer tandersättningen i tre steg. I första steget används en intraoral scanner istället för den traditionella avtryckstagningen (Mörmann et al., 2002; Beuer et al., 2008; Hehn, 2001). Man kan även scanna modeller och avtryck, vilket kan vara bra om patienten har svårt att gapa eller har hög salivproduktion, då scannrarna är känsliga för fuktiga miljöer (Kachalia et al., 2010). Det digitala avtrycket överförs till datorn, där uppgifterna bearbetas och en modell av tänderna skapas i 3D. I det andra steget designar tandläkaren tandersättningen på 3D-modellen. Här bestämmer tandläkaren kusphöjd, kontakter approximalt, utsträckning mot preparationsgränsen och utseende på tandersättningen. I det tredje steget fräses tandersättningen fram ur ett keramblock i en fräsmaskin. Ofta målas kronan här för att karaktärisera den och ge den ett mer tandlikt utseende innan den bränns i ugn. Med större möjligheter att själv kunna sköta hela processen fram till färdig tandkonstruktion måste tandläkaren fundera över hur kvaliteten och säkerheten hos de färdiga produkterna kan säkerställas. Färdiga tandtekniska arbeten räknas som specialanpassade medicintekniska produkter och ska inte CE-märkas men de material som ingår i arbetet är oftast CE-märkta. Lag (1993:584) om medicintekniska produkter och Läkemedelsverkets föreskrifter (LVFS 2003:11) om medicintekniska produkter innehåller krav på att medicintekniska produkter som släpps ut på marknaden ska vara lämpliga och säkra för sina användningsområden genom att krav ställs som ska leda till att allvarliga avvikelser, olyckor och tillbud på grund av produkterna så långt som möjligt ska kunna undvikas. Avvikelser inkluderar här både funktionsfel och misstänkta biverkningar. Innan ett tandtekniskt laboratorium får börja leverera tandtekniska arbeten till tandläkare måste ett antal krav vara uppfyllda för att bl.a. säkerställa säkerheten hos dessa produkter för patienterna. Laboratoriet ska vara registrerat hos Läkemedelsverket och vid registreringen måste man intyga att man har en tillverkningsverksamhet som uppfyller de krav för specialanpassade medicintekniska produkter som ställs i LVFS 2003:11. Medicintekniska produkter ska konstrueras och tillverkas på ett sådant sätt att de inte äventyrar patienternas kliniska tillstånd eller säkerhet, användarnas eller i förekommande fall andra personers hälsa och säkerhet, när de används under avsedda förhållanden och för sitt avsedda ändamål. Riskerna med att använda produkterna ska vara acceptabla med tanke på fördelarna för patienten och förenliga med en hög hälso-och säkerhetsnivå. Detta innefattar omfattande krav både på produkt och tillverkningsprocess. Det finns en del oklarheter rörande hur det regelverk som styr framställningen av tandtekniska arbeten tillämpas för arbeten tillverkade med chairside CAD/CAM.

  • 309.
    Berglund, Joann
    KTH, Skolan för teknik och hälsa (STH).
    Analys och uppdatering av utrustning för spirometri2012Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
  • 310.
    Bergqvist, Cecilia
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för neurokemi.
    Jafferali, Mohammed Hakim
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för neurokemi.
    Gudise, Santhosh
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för neurokemi.
    Markus, Robert
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för neurokemi.
    Hallberg, Einar
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för neurokemi.
    An inner nuclear membrane protein induces rapid differentiation of human induced pluripotent stem cells2017Inngår i: Stem Cell Research, ISSN 1873-5061, E-ISSN 1876-7753, Vol. 23, s. 33-38Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The ability of iPSCs (induced pluripotent stem cells) to generate any cell type in the body makes them valuable tools for cell replacement therapies. However, differentiation of iPSCs can be demanding, slowand variable. During differentiation chromatin is re-organized and silent dense heterochromatin becomes tethered to the nuclear periphery by processes involving the nuclear lamina and proteins of the INM(inner nuclearmembrane). The INM protein, Samp1 (Spindle AssociatedMembrane Protein 1) interacts with Lamin A/C and the INMprotein Emerin, which has a chromatin binding LEM(Lap2-Emerin-Man1)-domain. In this paperweinvestigate if Samp1 can play a role in the differentiation of iPSCs. Samp1 levels increased as differentiating iPSCs started to express Lamin A/C. Interestingly, even under pluripotent culturing conditions, ectopic expression of Samp1 induced a rapid differentiation of iPSCs, ofwhich some expressed the neuronal marker beta III-tubulin already after 6 days. This suggests that Samp1 is involved in early differentiation of iPSCs and could potentially be explored as a tool to promote progression of the differentiation process.

  • 311.
    Bergstrand, Maria
    KTH, Skolan för teknik och hälsa (STH), Ergonomi.
    Styckares arbetsmiljö: En studie om knivskärpa, olika knivstålskvaliteter, arbetssätt, samt fysisk ansträngning2011Independent thesis Advanced level (degree of Master (One Year)), 10 poäng / 15 hpOppgave
    Abstract [sv]

    Sammanfattning

     

    Styckare inom köttbranschen i Sverige ligger sedan länge i toppen av statistiken i Sverige, när det gäller yrken med de högsta relativa frekvenserna av anmälda arbetssjukdomar orsakade av belastningsfaktorer. Kniven är styckarens viktigaste verktyg och om den är slö ökar den fysiska belastningen med ökad risk för både belastningsskador och olycksfall. I denna studie på magisternivå var syftet att undersöka sambanden mellan knivens skärpa, knivens stålkvalitet, effekten av individens arbetssätt samt den fysiska ansträngningen vid styckning av nötkött. 12 personer vid två olika företag deltog i studien, under normalt arbete med styckning vid enkelbord under tre arbetsdagar. Tre olika knivstålskvaliteter utvärderades. Mätning av knivskärpa skedde med mätapparat Anago, samt med subjektiva skattningar enligt visuell analog skala (VAS). Tiden som kniven användes innan byte användes också som ett mått på hur länge skärpan kunde bibehållas. Ansträngningen hos styckarna undersöktes med mätning av hjärtfrekvensen under arbete, samt med skattning av ansträngning i händer och armar enligt VAS. Slutligen mättes eventuellt obehag/besvär före och under arbete med skattning enligt VAS.

     

    Det tycks som om det knivstål som var hårdare och inte finns på marknaden fungerade sämst, medan de övriga två var likvärdiga. Det finns indikationer på att det hårdare knivstålet påverkar andra egenskaper negativt, framförallt känslan av knivens följsamhet.

    Det föreligger en signifikant skillnad mellan olika individer i förmågan att bibehålla knivskärpa över tid, och de med obehag/besvär byter kniv oftare. Ytterligare studier krävs för att klargöra vad skillnaderna beror på, men sannolikt har både styckarens arbetsteknik, och företagets och individens rutiner för knivvård betydelse. Förbättrad utbildning inom dessa områden rekommenderas. Utvärderingen av knivtid indikerar att en styckare behöver 5-6 knivar per dag för att säkerställa att arbetet sker med vass kniv hela tiden.

    Det finns ett samband mellan dålig knivskärpa och lokal ansträngningskänsla i händer och armar. Något samband mellan knivskärpan och central ansträngning kunde dock inte påvisas i denna studie. Pulsvärdena visade att arbete som styckare innebär en hög belastning på andnings- och cirkulationsapparaten, och att de löper en stor risk att överskrida det rekommenderade gränsvärdet för energetisk belastning. Större undersökningsmaterial krävs dock för att dra säkrare slutsatser angående detta.

  • 312.
    Bergström, Madeleine
    Linköpings universitet, Institutionen för medicinsk teknik.
    Skin dose measurement during radiation therapy of mastectomy patients using GafChromicTM EBT3 films.2017Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Purpose: The aim of this study was to develop a method of measuring changes in the skin microcirculation and skin dose for mastectomy patients in connection with the radiation treatment. The distribution of the skin dose, its dependence on the energy of the beam, field geometry and bolus material and the accuracy of the given skin dose in the treatment planning system were studied. Finally, the correlation between the given dose and the changes in skin microcirculation was evaluated.

    Methods: Skin dose was measured using GafChromic EBT3 films. To evaluate the impact of different energies and field geometry measurements on a PMMA phantom were done. Dose measurements were done using an anthropomorphic phantom and in patients. The measured skin doses were compered to the doses calculated using the treatment planning system.

    Before and after treatment, skin blood perfusion was measured using laser speckle contrast imaging. In connection with the last measurement also methyl nicotinate was used to increase the perfusion for the measurement.

    Results: The measurements on the PMMA-phantom indicate that a larger photon energy results in a lower dose to the skin, but a higher exit dose. Furthermore a more oblique angle results in a higher skin dose and a larger field size also results in an increased skin dose.

    The patient measurements showed that the skin dose was significantly different in different areas of the irradiated field. The highest dose was measured in the area in which a bolus was applied. All patients showed a significant increase in skin blood of the perfusion within the irradiated area.

    The comparison between the measured doses and the doses calculated using the treatment planning system shows an underestimation of the skin dose by the treatment planning system depending on the incident angle and the presence of bolus material.

    Conclusion: The distribution of the skin dose during breast cancer radiotherapy in mastectomy patients is heterogeneous with the highest dose in the area of the mastectomy scar, due to the presence of bolus material. A correlation can be noticed between the changed in microcirculation and the radiation dose to the skin. Estimation of the skin dose using the treatment planning system is inaccurate, but film doseimetry offers an easy-to use method to accurately measure the dose to different areas of the irradiated skin. 

  • 313. Bergström, Mattias
    et al.
    Ericson, Åsa
    Larsson, Madelene
    Nergård, Henrik
    Larsson, Tobias
    Luleå Technical University.
    Renström, Boo
    Needs as a basis for design rationale2008Inngår i: / [ed] Dorian Marjanovic, Mario Storga, Neven Pavkovic, Nenad Bojcetic, University of Zagreb, Dubrovnik, Croatia: University of Zagreb , 2008Konferansepaper (Fagfellevurdert)
    Abstract [en]

    A basic principle for Needfinding [Faste, 1987; Patnaik & Becker, 1999] is that designers and engineers should interact directly with users to get direct insights into the user domain. Needfinding is not a new phenomena, it is almost forty years ago since the process was adopted at Stanford University’s product design program [Patnaik & Becker, 1999]. As the name, Need-finding, implies, this is an intertwined approach to find needs which are not readily articulated by users. The application of a Needfinding process offers qualitative methods to make those needs visible early on in product development. In fact, the process has become more interesting during recent time, since qualitative methods have gained more acceptance outside the academic realm [ibid.].The word qualitative indicates that what are sought for are qualities such as people’s experiences, what they perceive or interpret into a situation [Miles & Huberman, 1994; Patton, 2002]. Such data is contextually dependent, i.e., it must be generated in the context in which the phenomena occur. Besides context, people’s activities, behaviours and goals are important to observe and learn from. The objectives, for applying Needfinding, are to make the identification of needs and design a seamless effort, as well as an interest to identify opportunities to innovations. Needs last longer than any solution [Patnaik & Becker, 1999], since they are grounded in people’s activities. The solution and product that might meet such needs change over time. One example is how to store computer data, the products which satisfy the need has changed from, e.g., punch cards, magnetic tape, floppy discs [ibid.] to USB-flash memories. A guiding methodology in Needfinding is a flexible process, which is adapted to the task at hand [Kelley, 2001]. Such a process is conveyed in a few basic steps and, builds on a ‘philosophy’ which permeates all activities in order to adapt the process according to the project. Therefore, the designer’s ability to rely on such a process depends on familiarity with a number of methods for observations and interviews, as well as an aptitude for socio-technical skills. Hence, the purpose in this paper is to present and reflect on methods used in a running development project to identify needs in a product development project. This is done to contribute to the advancement of a need driven product development process. The disposition of this paper is as follows. First, our approach in studying the need identification activities is presented. Second, a theoretical frame for need identification and design is presented, i.e., Needfinding [Patnaik & Becker, 1999]. Third, the practice of finding needs is outlined and discussed.

  • 314.
    Bergström, Per
    et al.
    Luleå University of Technology.
    Khodadad, Davood
    Luleå University of Technology.
    Hällstig, Emil
    Optronic Partner dp AB.
    Sjödahl, Mikael
    Luleå University of Technology.
    Single Shot Shape Evaluation Using Dual-Wavelength Holographic Reconstructions and Regularization2013Inngår i: Fringe 2013: 7th International Workshop on Advanced Optical Imaging and Metrology / [ed] Wolfgang Osten, Springer, 2013, s. 103-108Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The aim of this work is to evaluate the shape of a free form object using single shot digital holography. The digital holography results in a gradient field and wrapped phase maps representing the shape of the object. The task is then to find a surface representation from this data which is an inverse problem. To solve this inverse problem we are using regularization with additional shape information from the CAD-model of the measured object.

  • 315. Bernard, Olivier
    et al.
    Bosch, J G
    Heyde, Brecht
    Alessandrini, Martino
    Barbosa, Daniel
    Camarasu-Pop, S
    Cervenansky, F
    Valette, S
    Mirea, O
    Bernier, M
    Jodoin, P M
    Domingos, J S
    Stebbing, R V
    Keraudren, K
    Oktay, O
    Caballero, J
    Shi, W
    Rueckert, D
    Milletari, F
    Ahmadi, S A
    Smistad, E
    Lindseth, F
    van Stralen, M
    Wang, Chunliang
    KTH, Skolan för teknik och hälsa (STH), Medicinsk teknik, Medicinsk bildbehandling och visualisering.
    Smedby, Örjan
    KTH, Skolan för teknik och hälsa (STH), Medicinsk teknik, Medicinsk bildbehandling och visualisering.
    Donal, E
    Monaghan, M
    Papachristidis, A
    Geleijnse, M L
    Galli, E
    Dhooge, Jan
    Standardized evaluation system for left ventricular segmentation algorithms in 3D echocardiography.2015Inngår i: IEEE Transactions on Medical Imaging, ISSN 0278-0062, E-ISSN 1558-254XArtikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Real-time 3D Echocardiography (RT3DE) has been proven to be an accurate tool for left ventricular (LV) volume assessment. However, identification of the LV endocardium remains a challenging task, mainly because of the low tissue/blood contrast of the images combined with typical artifacts. Several semi and fully automatic algorithms have been proposed for segmenting the endocardium in RT3DE data in order to extract relevant clinical indices, but a systematic and fair comparison between such methods has so far been impossible due to the lack of a publicly available common database. Here, we introduce a standardized evaluation framework to reliably evaluate and compare the performance of the algorithms developed to segment the LV border in RT3DE. A database consisting of 45 multivendor cardiac ultrasound recordings acquired at different centers with corresponding reference measurements from 3 experts are made available. The algorithms from nine research groups were quantitatively evaluated and compared using the proposed online platform. The results showed that the best methods produce promising results with respect to the experts' measurements for the extraction of clinical indices, and that they offer good segmentation precision in terms of mean distance error in the context of the experts' variability range. The platform remains open for new submissions.

  • 316.
    Berndtsson, Andreas
    KTH, Skolan för teknik och hälsa (STH), Medicinsk teknik.
    Heart Rate Variability Biofeedback for Android2013Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Heart rate variability (HRV) is the variations in time between consecutive heart beats, and reflects the functioning of the autonomic nervous system. Not only is HRV a good marker for many physiological disorders, but it is well known that HRV can be altered consciously by different approaches even though it is controlled by the autonomic nervous system. Respiration is an important factor in modulating HRV and this property is utilized in HRV biofeedback, which is a method that aims at increasing heart rate variability. HRV biofeedback systems typically measures heart rate variability and display the parameters on a screen, enabling the user to gain control and increase heart rate variations. In this thesis a software for biofeedback of heart rate variability is presented. The software was implemented for Android and runs on a tablet computer to make the biofeedback system portable and more accessible than most other biofeedback systems. The developed software has proven to be fully functional in real-time providing the user with reliable information. A small pilot study on healthy volunteers has also been made to evaluate the effects of the biofeedback training. These measurements give a preliminary indication that biofeedback session with the proposed solution increases HRV. However, a more comprehensive study with a larger population needs to be carried out in order to confidently confirm the positive effects of biofeedback sessions with the software. 

  • 317.
    Berner, Jessica
    Blekinge Tekniska Högskola, Fakulteten för hälsovetenskaper, Institutionen för hälsa.
    Psychosocial, Socio-Demographic and Health Determinants in Information Communication Technology Use by Older-Adults2014Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    The aim of the thesis was to investigate factors influencing ICT use by older-adults. A selection of psycho-social, socio-demographic and health determinants were investigated with Internet use. Data were collected through questionnaires (Studies I-III) and interviews (Study IV). Univariate and multivariate analyses were conducted, investigating Internet use as a dichotomous variable, with the aforementioned factors. The results indicated that psycho-social determinants did not affect older-adults’ Internet use (Study I). Scoring higher on the personality traits openness and extraversion did not affect whether the older adults started to use the Internet (Study II). However, well-being increased for some frail older-adults when using the tablet computer and connected to the Internet (Study IV). Some socio-demographic determinants affected Internet use. Being younger in age was a strong contributing factor in all four studies whether the older-adult would use the Internet. Higher education influenced Internet use (Study I & III), correlated with living in a rural or urban setting (Study III); yet education was not influencing whether they would start to use the Internet. Living alone was correlated with Internet use, especially if the older-adult lived in an urban setting (Study III). Functional disability and household economy did not affect Internet use. Finally, the health determinants on Internet use were quite strong. Normal cognitive functioning influenced whether older-adults would start to use the Internet (Study II). The older-adult living in an urban environment, would use the Internet if they had normal cognitive functioning (Study III). It was noted also from Study IV that the learning to use the Tablet PC and Skype took longer for older people and more repetition was needed. Being frail was a strong factor whether the older-adult would use the Internet. They would not want to learn or try to use the technology if they were too ill (Study IV). The findings show only a small increase (7.7%) in Internet use by older-adults over time. The indicators of non-use are: higher in age, lower educated, living alone or rurally, lower cognition and frailty. There are two different profiles of rural and urban Internet users. These determinants along with an understanding of the use of technology, and a good support system, are a few pillars in ICT adoption by older-adults. As ICT continues to develop as a means to provide better health care, it will be important to take into account the abovementioned indicators. In certain cases Internet use is not a given, which continues to exclude older-adults. Part of healthy aging is social participation; therefore being connected and included in the digital society is important. Alternative and not only one design solutions should be explored in health care and by organisations, so as to cater to the heterogeneity of the aging population.

  • 318.
    Beskow, Tua
    KTH, Skolan för teknik och hälsa (STH).
    Hip impact of the FE-model THUMS: Model adaptation and validation followed by an evaluation of the KTH developed shock absorbing floor system2016Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Abstract

    Fall accidents leads to an average of three deaths a day in Sweden. The high mortality and morbidity associated with falls among elderly is due to a high risk of falling caused by impaired mobility, sight and balance in combination with increased vulnerability as a result of fragile bones as well as comorbid conditions. Researchers at the department of Neuronics at KTH has developed a shock-absorbing floor that aim to reduce the risk of fall related fractures. The floors has shown promising results in mechanical drop tests but requires further analysis before it can be implemented in retirement homes.

    The goal of this master thesis is to refine, adapt and validate the finite element model THUMS 4.02 for fall simulations. The model will then be used to analyze the shock absorbing ability of various floor systems. Model adaptations included modification of the material properties of the adipose tissue and cartilage in the hips and implantation of tied internal contacts. Validation was performed against data from two experimental studies selected in a literature study, dynamic impact with isolated pelvis and lateral hip impact of complete PMHS.

    The experimental setups were reproduced in LS-Dyna and relatively close agreement for the force curves could be displayed in both cases. The model also showed realistic force response for fall simulations and a force reduction with up to 23% in simulation to the KTH developed floor system, differences could be seen for different fall positions of the model. Fall simulations agreed well with clinically and scientifically documented fracture loads and patterns. Further studies needs to be performed to further validate the model and analyze effect of different geometrical properties of floor system.

  • 319. Beyene, Ayne A.
    et al.
    Welemariam, Tewelle
    Persson, Marie
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för datalogi och datorsystemteknik.
    Lavesson, Niklas
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för datalogi och datorsystemteknik.
    Improved concept drift handling in surgery prediction and other applications2015Inngår i: Knowledge and Information Systems, ISSN 0219-1377, Vol. 44, nr 1, s. 177-196Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The article presents a new algorithm for handling concept drift: the Trigger-based Ensemble (TBE) is designed to handle concept drift in surgery prediction but it is shown to perform well for other classification problems as well. At the primary care, queries about the need for surgical treatment are referred to a surgeon specialist. At the secondary care, referrals are reviewed by a team of specialists. The possible outcomes of this review are that the referral: (i) is canceled, (ii) needs to be complemented, or (iii) is predicted to lead to surgery. In the third case, the referred patient is scheduled for an appointment with a surgeon specialist. This article focuses on the binary prediction of case three (surgery prediction). The guidelines for the referral and the review of the referral are changed due to, e.g., scientific developments and clinical practices. Existing decision support is based on the expert systems approach, which usually requires manual updates when changes in clinical practice occur. In order to automatically revise decision rules, the occurrence of concept drift (CD) must be detected and handled. The existing CD handling techniques are often specialized; it is challenging to develop a more generic technique that performs well regardless of CD type. Experiments are conducted to measure the impact of CD on prediction performance and to reduce CD impact. The experiments evaluate and compare TBE to three existing CD handling methods (AWE, Active Classifier, and Learn++) on one real-world dataset and one artificial dataset. TBA significantly outperforms the other algorithms on both datasets but is less accurate on noisy synthetic variations of the real-world dataset.

  • 320. Beyene, Ayne A.
    et al.
    Welemariam, Tewelle
    Persson, Marie
    Blekinge Tekniska Högskola, Institutionen för datalogi och datorsystemteknik.
    Lavesson, Niklas
    Blekinge Tekniska Högskola, Institutionen för datalogi och datorsystemteknik.
    Improved concept drift handling in surgery prediction and other applications2015Inngår i: Knowledge and Information Systems, ISSN 0219-1377, E-ISSN 0219-3116, Vol. 44, nr 1, s. 177-196Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The article presents a new algorithm for handling concept drift: the Trigger-based Ensemble (TBE) is designed to handle concept drift in surgery prediction but it is shown to perform well for other classification problems as well. At the primary care, queries about the need for surgical treatment are referred to a surgeon specialist. At the secondary care, referrals are reviewed by a team of specialists. The possible outcomes of this review are that the referral: (i) is canceled, (ii) needs to be complemented, or (iii) is predicted to lead to surgery. In the third case, the referred patient is scheduled for an appointment with a surgeon specialist. This article focuses on the binary prediction of case three (surgery prediction). The guidelines for the referral and the review of the referral are changed due to, e.g., scientific developments and clinical practices. Existing decision support is based on the expert systems approach, which usually requires manual updates when changes in clinical practice occur. In order to automatically revise decision rules, the occurrence of concept drift (CD) must be detected and handled. The existing CD handling techniques are often specialized; it is challenging to develop a more generic technique that performs well regardless of CD type. Experiments are conducted to measure the impact of CD on prediction performance and to reduce CD impact. The experiments evaluate and compare TBE to three existing CD handling methods (AWE, Active Classifier, and Learn++) on one real-world dataset and one artificial dataset. TBA significantly outperforms the other algorithms on both datasets but is less accurate on noisy synthetic variations of the real-world dataset.

  • 321. Bhatt, Manish
    et al.
    Ayyalasomayajula, Kalyan R.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Avdelningen för visuell information och interaktion. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Bildanalys och människa-datorinteraktion.
    Yalavarthy, Phaneendra K.
    Generalized Beer–Lambert model for near-infrared light propagation in thick biological tissues2016Inngår i: Journal of Biomedical Optics, ISSN 1083-3668, E-ISSN 1560-2281, Vol. 21, nr 7, artikkel-id 076012Artikkel i tidsskrift (Fagfellevurdert)
  • 322.
    Bianchi, Kevin
    et al.
    ISIT UMR6284 CNRS, Univ. d’Auvergne BP10448, F-63000 Clermont-Ferrand.
    Vacavant, Antoine
    ISIT UMR6284 CNRS, Univ. d’Auvergne BP10448, F-63000 Clermont-Ferrand.
    Strand, Robin
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Avdelningen för visuell information och interaktion. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Bildanalys och människa-datorinteraktion.
    Terve, Pierre
    KEOSYS Company 1, impasse Auguste Fresnel, F 44815 Saint Herblain.
    Sarry, Laurent
    ISIT UMR6284 CNRS, Univ. d’Auvergne BP10448, F-63000 Clermont-Ferrand.
    Dual B-spline Snake for Interactive Myocardial Segmentation2013Konferansepaper (Fagfellevurdert)
    Abstract [en]

    This paper presents a novel interactive segmentation formalism based on two coupledB-Spline snake models to efficiently and simultaneously extract myocardial walls fromshort-axis magnetic resonance images. The main added value of this model is interactionas it is possible to quickly and intuitively correct the result in complex cases withoutrestarting the whole segmentation working flow. During this process, energies computedfrom the images guide the user to the best position of the model.

  • 323.
    Biasetti, Jacopo
    KTH, Skolan för teknikvetenskap (SCI), Hållfasthetslära (Inst.).
    On the interplay between hemodynamics and biochemsitry of the normal and aneurysmatic abdominal aorta2011Licentiatavhandling, med artikler (Annet vitenskapelig)
  • 324.
    Biasetti, Jacopo
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Hållfasthetslära (Inst.), Biomekanik.
    Gasser, T. Christian
    KTH, Skolan för teknikvetenskap (SCI), Hållfasthetslära (Inst.), Biomekanik.
    Auer, Martin
    VASCOPS GmbH, Graz, Austria.
    Hedin, Ulf
    Department of Molecular Medicine and Surgery, Karolinska Universty Hospital, Stockholm, Sweden.
    Labruto, Fausto
    Department of Radoilogy, Karolinska University Hospital, Stockholm, Sweden.
    Hemodynamics of the Normal Aorta Compared to Fusiform and Saccular Abdominal Aortic Aneurysms with Emphasis on a Potential Thrombus Formation Mechanism2010Inngår i: Annals of Biomedical Engineering, ISSN 0090-6964, E-ISSN 1573-9686, Vol. 38, nr 2, s. 380-390Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Abdominal Aortic Aneurysms (AAAs), i.e., focal enlargements of the aorta in the abdomen are frequently observed in the elderly population and their rupture is highly mortal. An intra-luminal thrombus is found in nearly all aneurysms of clinically relevant size and multiply affects the underlying wall. However, from a biomechanical perspective thrombus development and its relation to aneurysm rupture is still not clearly understood. In order to explore the impact of blood flow on thrombus development, normal aortas (n = 4), fusiform AAAs (n = 3), and saccular AAAs (n = 2) were compared on the basis of unsteady Computational Fluid Dynamics simulations. To this end patient-specific luminal geometries were segmented from Computerized Tomography Angiography data and five full heart cycles using physiologically realistic boundary conditions were analyzed. Simulations were carried out with computational grids of about half a million finite volume elements and the Carreau-Yasuda model captured the non-Newtonian behavior of blood. In contrast to the normal aorta the flow in aneurysm was highly disturbed and, particularly right after the neck, flow separation involving regions of high streaming velocities and high shear stresses were observed. Naturally, at the expanded sites of the aneurysm average flow velocity and wall shear stress were much lower compared to normal aortas. These findings suggest platelets activation right after the neck, i.e., within zones of pronounced recirculation, and platelet adhesion, i.e., thrombus formation, downstream. This mechanism is supported by recirculation zones promoting the advection of activated platelets to the wall.

  • 325.
    Biasetti, Jacopo
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Hållfasthetslära (Inst.), Biomekanik.
    Gasser, Thomas Christian
    KTH, Skolan för teknikvetenskap (SCI), Hållfasthetslära (Inst.), Biomekanik.
    A Blood Flow based model for Platelet Activation in Abdominal Aortic Aneurisms2010Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Introduction

    Thrombus formation is the physiological response to vascular injury, it prevents loss of blood and permits wound healing, however, it is also associated with pathological conditions like hypoxia, anoxia and infarction [1]. Consequently, thrombus development must be carefully modulated to avoid uncontrolled growth, which in turn could lead to organ malfunctions. Specifically, an Intra-Luminal Thrombus (ILT) is found in almost all larger (clinically relevant) Abdominal Aortic Aneurysms (AAAs) and multiple biochemical [2] and biomechanical [3] implications on the underlying wall tissue have been reported. Despite the dominant role played by the ILT in AAA disease little is known regarding its development, and hence, the present study investigates ILT formation with particular emphasis on platelet activation triggered by biomechanical and biochemical field variables.

    Method

    The proposed model assumes that platelet activation is defined by a single field variable

    representing the accumulation of mechanical [4] and chemical [5] factors as the platelet moves along its path line. Platelet activation is given as soon asovercomes a certain threshold thought to be a constitutive property of blood. Specifically, the rate of the activation variable is determined by the maximum shear stress and the local concentrations of agonists and antagonists. To implement the model the fluid mechanical problem was solved in (COMSOL, COMSOL AB) and a particle tracking analysis (MATLAB, The MathWorks) was applied as a post processing step. The flow in a circular tube and the Backward Facing Step (BFS) problem under varying initial conditions were used for a basic investigation of the model and to relate its predictions to available data in the literature. Finally, platelet activation in patient specific AAAs was predicted and related to ILT development, which was estimated from Computer Tomography-Angiography (CT-A) data recorded from patient follow-up studies.

    Results and Conclusions

    The platelet activation variable

     is complex distributed (highly heterogeneous) in the flow field, where, specifically, at the boundary of vortexes [6] and in the boundary layer of the non- endothelialized wall highest values were predicted. Continuous release of antagonists from the endothelialized wall lowers  in its vicinity, and hence, despite the high shear stress platelet activation

    is prevented. The proposed model links biomechanical and biochemical mechanisms of platelet activation and is able to predict the onset of thrombus formation of the BFS problem. The model is also able to predict some features of ILT development in the AAA, however, the change in luminal geometry is a cumulative effect of ILT growth, wall growth and their mechanical interactions, and hence, data recorded form patient follow-up studies needs to be analyzed carefully when validating the present model.

    References

    [1] J. D. Humphrey,

    Springer-Verlag, New York, 2002.

    [2] M. Kazi, et. al.

    J. Vasc. Surg., 38:1283-1292, 2003.

    [3] W. R. Mower et. al.,

    J. Vasc. Surg., 33:602-608, 1997.

    [4] J. D. Hellums,

    Ann. Biomed. Eng., 22: 445-455, 1994.

    [5] B. Alberts et. al.

    Molecular Biology of the cell, 2002.

    [6] J. Biasetti et. al.

    Ann. Biomed. Eng., 38: 380–390 2010.

  • 326.
    Biasetti, Jacopo
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Hållfasthetslära (Inst.), Biomekanik.
    Gasser, Thomas Christian
    KTH, Skolan för teknikvetenskap (SCI), Hållfasthetslära (Inst.), Biomekanik.
    A Fluid-chemical model of thrombus formation2011Inngår i: CMBE2011: 2nd International Conference on Mathematical and Computational Biomedical Engineering / [ed] P. Nithiarasu, R. Löhner, 2011Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Our understanding of the genesis and evolution of Abdominal Aortic Aneurysms (AAAs), withparticular emphasis on Intra-Luminal Thrombus’ evolution, may be improved by studying thecomplex interplay between fluid-dynamics and biochemistry. To investigate the evolution of prothromboticchemicals inside the blood flow, in particular thrombin (factor IIa), a fluido-chemicalmodel has been developed. To this end a series of convection-diffusion-reaction (CDR) equationsdescribing the tissue factor pathway to thrombin have been solved on top of the biofluiddynamics problem. The proposed model integrates biochemistry and fluids dynamics, and hence,supports a comprehensive understanding of how ILT in AAAs may develop.

  • 327.
    Biasetti, Jacopo
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Hållfasthetslära (Inst.), Biomekanik.
    Hussain, Fazle
    Department of Mechanical Engineering, University of Houston, Houstohn, TX, USA.
    Gasser, T. Christian
    KTH, Skolan för teknikvetenskap (SCI), Hållfasthetslära (Inst.), Biomekanik.
    Blood flow and coherent vortices in the normal and aneurysmatic aortas: a fluid dynamical approach to intraluminal thrombus formation2011Inngår i: Journal of the Royal Society Interface, ISSN 1742-5689, E-ISSN 1742-5662, Vol. 8, nr 63, s. 1449-1461Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Abdominal aortic aneurysms (AAAs) are frequently characterized by the development of an intra-luminal thrombus (ILT), which is known to have multiple biochemical and biomechanical implications. Development of the ILT is not well understood, and shear-stress-triggered activation of platelets could be the first step in its evolution. Vortical structures (VSs) in the flow affect platelet dynamics, which motivated the present study of a possible correlation between VS and ILT formation in AAAs. VSs educed by the lambda(2)-method using computational fluid dynamics simulations of the backward-facing step problem, normal aorta, fusiform AAA and saccular AAA were investigated. Patient-specific luminal geometries were reconstructed from computed tomography scans, and Newtonian and Carreau-Yasuda models were used to capture salient rheological features of blood flow. Particularly in complex flow domains, results depended on the constitutive model. VSs developed all along the normal aorta, showing that a clear correlation between VSs and high wall shear stress (WSS) existed, and that VSs started to break up during late systole. In contrast, in the fusiform AAA, large VSs developed at sites of tortuous geometry and high WSS, occupying the entire lumen, and lasting over the entire cardiac cycle. Downward motion of VSs in the AAA was in the range of a few centimetres per cardiac cycle, and with a VS burst at that location, the release (from VSs) of shear-stress-activated platelets and their deposition to the wall was within the lower part of the diseased artery, i.e. where the thickest ILT layer is typically observed. In the saccular AAA, only one VS was found near the healthy portion of the aorta, while in the aneurysmatic bulge, no VSs occurred. We present a fluid-dynamics-motivated mechanism for platelet activation, convection and deposition in AAAs that has the potential of improving our current understanding of the pathophysiology of fluid-driven ILT growth.

  • 328.
    Biasetti, Jacopo
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Hållfasthetslära (Inst.).
    Spazzini, Pier Giorgio
    Mechanics Division, National Institute of Metrological Research (INRiM), Turin, Italy.
    Gasser, Christian
    KTH, Skolan för teknikvetenskap (SCI), Hållfasthetslära (Inst.).
    An integrated fluido-chemical model towards modeling the formation of intra-luminal thrombus in abdominal aortic aneurysms2011Artikkel i tidsskrift (Annet vitenskapelig)
    Abstract [en]

    Abdominal Aortic Aneurysms (AAAs) are frequently characterized by the presence of an Intra-Luminal Thrombus (ILT) known to influence biochemically and biomechanically their evolution. ILT progression mechanism is still unclear and little is known regarding the impact of chemicals transported by blood flow. It is expected that chemical agonists and antagonists of platelets activation, aggregation, and adhesion play an important role in ILT development. Starting fromthis assumption, the evolution of chemical species related to the coagulation cascade (CC), their relation to coherent vortical structures (VSs) and their effect on ILT evolution have been studied. To this end a fluido-chemical model that simulates the CC through a series of convection-diffusion-reaction (CDR) equations and considers blood as a non-Newtonian incompressible fluid has been developed. In addition to the relation between VSs and thrombin distribution, high thrombin concentrations at the distal portion of the AAA were observed, i.e. the region where the thickest ILT is usually seen. The proposed model, due to its ability to couple the fluid and chemical domains, provides an integrated mechanochemical picture that potentially could unveil mechanisms of ILT formation and development.

  • 329.
    Birkeland, Åsmund
    et al.
    Department of Information, University of Bergen, Norway.
    Solteszova, Veronika
    Hönigmann, Dieter
    Helge Gilja, Odd
    Brekke, Svein
    Ropinski, Timo
    Viola, Ivan
    The Ultrasound Visualization Pipeline - A Survey2012Annet (Annet vitenskapelig)
    Abstract [en]

    Ultrasound is one of the most frequently used imaging modality in medicine. The high spatial resolution, its interactive nature and non-invasiveness makes it the first choice in many examinations. Image interpretation is one of ultrasound's main challenges. Much training is required to obtain a confident skill level in ultrasound-based diagnostics. State-of-the-art graphics techniques is needed to provide meaningful visualizations of ultrasound in real-time. In this paper we present the process-pipeline for ultrasound visualization, including an overview of the tasks performed in the specific steps. To provide an insight into the trends of ultrasound visualization research, we have selected a set of significant publications and divided them into a technique-based taxonomy covering the topics pre-processing, segmentation, registration, rendering and augmented reality. For the different technique types we discuss the difference between ultrasound-based techniques and techniques for other modalities.

  • 330.
    Bitaraf, Nazanin
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    The electrophysiological response of medial preoptic neurons to hypoxia and development of a system for patch-clamp measurement with full oxygen control2011Licentiatavhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    A stroke is caused by interruption of the blood supply to the brain. Yearly 15 million people around the globe endure a stroke and the costs and suffering for the people involved and the society are immense. The aim of this thesis was to investigate the response to oxygen deprivation in neurons from the medial preoptic nucleus (MPN) that have a high abundance of neuroglobin. The long term goal is to investigate the neuroprotective role of the protein in relation to stroke. Initially, the electrophysiological response of neurons to hypoxic exposure in an open system was assessed with a conventional patch-clamp setup. The first aim was to see how well the conventional system worked and if it needed improvement. Secondly, the MPN had never been investigated regarding oxygen, deprivation; hence the electrophysiological response under hypoxia needed to be investigated. The conventional patch-clamp system only allowed a reduction of the oxygen content to a level of 3-6% but not total control of the cell environment. The medial preoptic neurons showed mainly an increase of their resting membrane potential at hypoxia. The voltage activated Ca2+ and K+ currents displayed a clear attenuation when cells were subjected to hypoxia. Non-L-type Ca2+ channels were affected by hypoxic exposure and one cell indicated participation of Ca2+ activated K+ channels. However, a response could only be seen in approximately fifty percent of the neurons in the open system. This may have been due to the fact that full control of the oxygen around the neurons at hypoxia could not be achieved. A new system with full control of the ambient oxygen had to be developed in order to investigate this. After the conclusions of the first experiments, a system was developed were a labon- a-chip system was combined with the patch-clamp technique. A microfluidic system with a patch-clamp micropipette integrated was combined with optical tweezers for 3D maneuvering of the neurons. The development of patch-clamp in combination with a microfluidic system and optical tweezers allowed for full oxygen control. The experiments showed that the electrophysiological measurements were not affected by the laser when an infrared laser was used. The microfluidic system allowed very good oxygen control reaching levels of 0.5-1.5 % compared to 3-6 % in the open system. In summary, this work suggests that high voltage activated Ca2+ channels, and K+ channels are involved in the hypoxic depolarization of medial preoptic neurons. Full control of ambient oxygen in cell vicinity could be achieved by the combination of microfluidics, patch-clamp and optical tweezers. The results can be used in future studies to better understand the reaction of the brain to oxygen deprivation caused by stroke.

  • 331.
    Bitaraf, Nazanin
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Alrifaiy, Ahmed
    Luleå tekniska universitet.
    Druzin, Mikhail
    Umeå University, Department of Integrative Medical Biology, Physiology.
    Ramser, Kerstin
    Development of a multifunctional microfluidic system for studies of nerve cell activity during hypoxic and anoxic conditions2009Inngår i: World Congress on Medical Physics and Biomedical Engineering: September 7 - 12, 2009, Munich, Germany, Berlin: Springer Science+Business Media B.V., 2009, Vol. 8, s. 176-179Konferansepaper (Fagfellevurdert)
  • 332. Bitaraf, Nazanin
    et al.
    Druzin, Mikhail
    Umeå University, Integrative Medical Biology, Physiology.
    Lindahl, Olof
    Ramser, Kerstin
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Elektrofysiologiska mätningar på MPN-neuroner under hypoxi: ett steg mot profylaktisk behandling av patienter i riskzonen för stroke2010Inngår i: Medicinteknikdagarana 2010, 2010Konferansepaper (Annet vitenskapelig)
  • 333. Bitaraf, Nazanin
    et al.
    Ramser, Kerstin
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Alrifaiy, Ahmed
    Multipla mätningar på enstaka celler i ett mikroflödessystem2009Konferansepaper (Annet vitenskapelig)
  • 334.
    Bjering, Beatrice
    et al.
    KTH, Skolan för teknik och hälsa (STH).
    Forss, Elin
    KTH, Skolan för teknik och hälsa (STH).
    Videoanalys av sekvenser i ishockey där en tackling resulterat i hjärnskakning2017Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [en]

    There is a major issue with concussion within contact sports and one of these sports is ice hockey. Concussions have a negative effect on health and repeated concussions, which often occur in ice hockey, can force players to retire early. Since it is such a major problem that can result in serious consequences, a better understanding within the field is needed. This report has focused on speeds right before a player was tackled as well as the players contact body parts. The information was collected by analyzing 10 video clips where a tackle took place that resulted in a concussion. The video clips were analyzed using the software SkillSpector, where 3D speeds were collected for both the attacking and the injured players. The contact body parts were also identified during the analysis. The results were compared to a reference group from an earlier bachelor degree project where tackles that did not result in a concussion were analyzed. The conclusion from this project is that the speeds for the players in the interest group were proven to have a significantly higher mean speed than the players from the earlier project. Furthermore, the results indicate that the tackled players speed can have a larger impact on the outcome of the tackle than the speed of the attacking player. From the results in this project it is shown that, of the tackles that could lead to a concussion, shoulder to jaw was the most common combination.

  • 335.
    Björling, Gunilla
    et al.
    Röda Korsets Högskola, Avdelningen Vård och Omvårdnad. Karolinska Institutet.
    Aune, R.
    The Norwegian University of Science and technology, Trondheim, Norway.
    Strömberg, E.
    KTH.
    Lindberg, J.
    Karolinska Institutet.
    Burgstaller, C.
    Transfercenter fur Kunststofftechnik GMBH, Vienna, Austria.
    Egizabal, A.
    Fundaction Tecnalia Research & Innovation, TECNALIA, Madrid, Spain.
    Liljegren, A.
    Karolinska Institutet.
    Ehlen, B.
    Boukje.com Consulting BV, Amsterdam, Netherlands.
    Grønberg, B. H.
    St Olav hospital, Trondheim, Norway.
    Vermeiren, P.
    Health Leads BV, Amsterdam, Netherlands.
    Namy, P.
    SIMTEC EURL, Paris, France.
    Mancini, T.
    Universita Degli Studi di Roma La Sapienza, Rome, Italy.
    Karlsson, S.
    KTH.
    Vullum-Bruer, F.
    The Norwegian University of Science and technology, Trondheim, Norway.
    Frostell, C.
    Karolinska Institutet.
    Risk Evaluation of Therapy Medical Devices and Implants for Increased Patient Safety: REMISS Horizon 2020 Research and Innovation Action2017Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Current knowledge in the area of medical devices remains insufficiently complete, and many of the established test methods and international standards (ISO (International Organization for Standardization) standards) open up to individual interpretation on how the test should be performed and the results reported. Treating long-term diseases such as cancer imposes a stringent sequence of various treatments on patients. For instance, cancer may be treated with radiation and chemotherapy; the latter in many treatment protocols requiring the implantation of an intravascular catheter during a prolonged period of time. To maximize the effect of such measures, as well as issues related to the patient Health Related Quality of Life (HRQoL), integrated and validated methodologies are needed as decisional basis for appropriate risk management and patient safety with regard to clinical use of intravascular catheters.

    The ambition of the REMISS project is to: Establish integrated and validated methodologies for risk management of the clinical use of intravascular catheters with respect to the clinical service lifetime, improved patient treatment, safety and HRQoL. This is assumed to reduce patient suffering due to complications associated with material deployment and degradation associated side effects for e.g. cancer patients receiving treatment with chemotherapeutical drugs using an intravascular catheter.

    The main vision is to improve the standards for eliminating side effects (complications) caused by deployment from and degradation of intravascular catheters, as well as loss of performance due to material-drug-biological system interactions, compared to the current state-of-the-art. Realising the project goals the rate of catheter-associated complications can be lowered by 40-50%, which in turn will improve patient treatment, safety and HRQoL, as well as health care related costs.

    Package integrally developed methodologies, predictive models, databases, and other project findings, as a potential product with a holistic coverage. It is believed that commercialisation of (selected) results will be the best option in order to create sustainable availability of this service based on continued research on intravascular catheters according to integrated and validated methodologies.REMISS answer the call NMBP-12-2017 Development of a Reliable Methodology for Better Risk Management of Engineered Biomaterials Advanced Therapy Medicinal Products and/or Medical Devices Marcy, P. Central venous access: techniques and indications in oncology. European Society of Radiology, 2008; 18; 2333-44 Maki DG, et al The risk of bloodstream infection in adults with different intravascular devices: a systematic review of 200 published prospective studies. Mayo Clin Proc 2006: 81 (9): 1159-71. Frostell, C., Björling, G., Strömberg, E., Karlsson, S., and Aune, R. E., Tracheal Implants Revisited, The Lancet (2017), 389(10075) pp.1191

  • 336. Bjurman, Christian
    et al.
    Petzold, Max
    Venge, Per
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för medicinska vetenskaper, Biokemisk struktur och funktion.
    Farbemo, Julia
    Fu, Michael L. X.
    Hammarsten, Ola
    High-sensitive cardiac troponin, NT-proBNP, hFABP and copeptin levels in relation to glomerular filtration rates and a medical record of cardiovascular disease2015Inngår i: Clinical Biochemistry, ISSN 0009-9120, E-ISSN 1873-2933, Vol. 48, nr 4-5, s. 302-307Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Background: Elevation of cardiac markers in patients with renal dysfunction has not been fully assessed reducing the diagnostic usefulness of these biomarkers. Objective: To examine the effects of renal function and a medical record of cardiovascular disease on levels of cardiac biomarkers. Methods: Serum samples were collected from 489 patients referred for GFR measurement using Cr51-EDTA or iohexol plasma clearance (measured GFR). The cardiac biomaiters Troponin T (hs-cTnT), Troponin I (hsTnI), N-Terminal pro Brain Natriuretic Peptide (NTproBNP), Copeptin, Human Fatty Acid Binding Protein (hFABP), as well as the kidney function biomarkers creatinine and cystatin C, were measured. Regression was used to analyse the relationship between biomarker levels and the glomerular filtration rate (GFR) between 15 and 90 mL/min/1.73 m(2). Results: Compared with normal kidney function, the estimated increases in the studied cardiac biomarkers at a CUR of 15 mL/mM/1.73 m(2) varied from 2-fold to 15 fold but were not very different between patients with or without a medical record of cardiovascular disease and were most prominent for cardiac biomarkers with low molecular weight. hs-cTnT levels correlated more strongly to measured CUR and increased more at low CUR compared to hs-cTnI. For hFABP and NT-proBNP increases at low kidney function were more correctly predicted by a local Cystatin C-based eGFR formula compared with creatinine-based eGFR (using the MDRD or CKD-EPI equations) Conclusion: The extent of the elevation of cardiac markers at low renal function is highly variable. For hFABP and NTproBNP Cystatin C-based eGFR provides better predictions of the extent of elevation compared to the MDRD or CKD-EPI equations. (C) 2015 The Authors. The Canadian Society of Clinical Chemists. Published by Elsevier Inc. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd,40/).

  • 337.
    Bjällmark, Anna
    et al.
    KTH, Medicinsk teknik.
    Gustafsson, U
    Brodin, Lars-Åke
    KTH, Medicinsk teknik.
    Waldenström, A
    Larsson, Matilda
    KTH, Medicinsk teknik.
    A system to quantify and visualize ventricular rotation pattern of the heart2009Patent (Annet (populærvitenskap, debatt, mm))
    Abstract [en]

    Different modalities have been used to describe the rotational motion of the ventricles of the heart and studies have indicated LV twist to be an additional integral component in LV function. So far, only amplitudes and timings of rotation have been reported, whereas no method is available to fully describe the rotation pattern of the ventricles. The object of the present application is to achieve a system that presents a novel way to quantify and visualize the ventricular rotation pattern of the heart. We present a novel method that assesses and describes the rotation pattern by calculating the rotation axis of the ventricle. Non- invasive image acquisition is required to collect rotation values from different positions of the myocardium. Thereafter, a kinematic model of a ventricle is constructed to determine the rotation planes at different levels of the heart. The motion of the rotation planes are visualized by plotting the normal vectors of the planes over time, i.e. the rotation axis of the planes. This new method is different to all other methods used today for assessing cardiac function, as it does not describe the amplitude of a motion but the relationship in motion between different parts within a ventricle. Preliminary results indicate that the rotation axis is more sensitive to changes in the rotation pattern than conventional measurements of ventricular rotation. This new method could be used for early detection of cardiac diseases and for selection of patients for and optimization of cardiac resynchronization therapy.

  • 338.
    Bjällmark, Anna
    et al.
    KTH, Skolan för teknik och hälsa (STH), Medicinsk teknik.
    Gustafsson, U
    Brodin, Lars-Åke
    KTH, Skolan för teknik och hälsa (STH), Medicinsk teknik.
    Waldenström, A
    Larsson, Matilda
    KTH, Skolan för teknik och hälsa (STH), Medicinsk teknik.
    A system to quantify and visualize ventricular rotation pattern of the heart2009Patent (Annet (populærvitenskap, debatt, mm))
    Abstract [en]

    Different modalities have been used to describe the rotational motion of the ventricles of the heart and studies have indicated LV twist to be an additional integral component in LV function. So far, only amplitudes and timings of rotation have been reported, whereas no method is available to fully describe the rotation pattern of the ventricles. The object of the present application is to achieve a system that presents a novel way to quantify and visualize the ventricular rotation pattern of the heart. We present a novel method that assesses and describes the rotation pattern by calculating the rotation axis of the ventricle. Non- invasive image acquisition is required to collect rotation values from different positions of the myocardium. Thereafter, a kinematic model of a ventricle is constructed to determine the rotation planes at different levels of the heart. The motion of the rotation planes are visualized by plotting the normal vectors of the planes over time, i.e. the rotation axis of the planes. This new method is different to all other methods used today for assessing cardiac function, as it does not describe the amplitude of a motion but the relationship in motion between different parts within a ventricle. Preliminary results indicate that the rotation axis is more sensitive to changes in the rotation pattern than conventional measurements of ventricular rotation. This new method could be used for early detection of cardiac diseases and for selection of patients for and optimization of cardiac resynchronization therapy.

  • 339.
    Bjällmark, Anna
    et al.
    KTH, Medicinsk teknik.
    Larsson, Matilda
    KTH, Medicinsk teknik.
    Brodin, Lars-Åke
    KTH, Medicinsk teknik.
    Nowak, Jacek
    Lind, Britta
    KTH, Medicinsk teknik.
    Hayashi, Shirley
    Mazza do Nascimento, Marcelo
    Riella, Miquel
    Seeberger, Astrid
    Effects of hemodialysis on the cardiovascular system: Quantitative analysis using wave intensity wall analysis and tissue velocity imaging2010Inngår i: Heart and Vessels, ISSN 0910-8327, E-ISSN 1615-2573Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Cardiovascular disease is the leading cause of death in patients with end stage renal disease (ESRD). The aim of this study was to investigate the changes in cardiovascular function induced by a single session of hemodialysis (HD) by the analysis of cardiovascular dynamics using wave intensity wall analysis (WIWA) and of systolic and diastolic myocardial function using tissue velocity imaging (TVI). Grey-scale cine loops of the left common carotid artery, conventional echocardiography and TVI images of the left ventricle were acquired before and after HD in 45 patients (17 women, mean age 54) with ESRD. The WIWA indexes, W1 preload-adjusted W1, W2 and preload-adjusted W2, and the TVI variables, isovolumic contraction velocity (IVCV), isovolumic contraction time (IVCT), peak systolic velocity (PSV), displacement, isovolumic relaxation velocity (IVRV), isovolumic relaxation time (IVRT), peak early diastolic velocity (E’) and peak late diastolic velocity (A’), were compared before and after HD. The WIWA measurements showed significant increases in W1 (p < 0.05) and preload-adjusted W1 (p < 0.01) after HD. W2 was significantly decreased (p < 0.05) after HD, whereas the change in preload-adjusted W2 was not significant. Systolic velocities, IVCV (p < 0.001) and PSV (p < 0.01), were increased after HD, whereas the AV-plane displacement were decreased (p < 0.01). For the measured diastolic variables, E’ was significantly decreased (p < 0.01) and IVRT was significantly prolonged (p < 0.05), after HD. A few correlations were found between WIWA and TVI variables. The WIWA and TVI measurements indicate that a single session of HD improves systolic function. The load dependency of the diastolic variables seems to be more pronounced than for the systolic variables. Preload-adjusted wave intensity indexes may contribute in the assessment of true LV contractility and relaxation.

  • 340.
    Bjällmark, Anna
    et al.
    KTH, Skolan för teknik och hälsa (STH), Medicinsk teknik.
    Larsson, Matilda
    KTH, Skolan för teknik och hälsa (STH), Medicinsk teknik.
    Brodin, Lars-Åke
    KTH, Skolan för teknik och hälsa (STH), Medicinsk teknik.
    Nowak, Jacek
    Lind, Britta
    KTH, Skolan för teknik och hälsa (STH), Medicinsk teknik.
    Hayashi, Shirley
    Mazza do Nascimento, Marcelo
    Riella, Miquel
    Seeberger, Astrid
    Effects of hemodialysis on the cardiovascular system: Quantitative analysis using wave intensity wall analysis and tissue velocity imaging2010Inngår i: Heart and Vessels, ISSN 0910-8327, E-ISSN 1615-2573Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Cardiovascular disease is the leading cause of death in patients with end stage renal disease (ESRD). The aim of this study was to investigate the changes in cardiovascular function induced by a single session of hemodialysis (HD) by the analysis of cardiovascular dynamics using wave intensity wall analysis (WIWA) and of systolic and diastolic myocardial function using tissue velocity imaging (TVI). Grey-scale cine loops of the left common carotid artery, conventional echocardiography and TVI images of the left ventricle were acquired before and after HD in 45 patients (17 women, mean age 54) with ESRD. The WIWA indexes, W1 preload-adjusted W1, W2 and preload-adjusted W2, and the TVI variables, isovolumic contraction velocity (IVCV), isovolumic contraction time (IVCT), peak systolic velocity (PSV), displacement, isovolumic relaxation velocity (IVRV), isovolumic relaxation time (IVRT), peak early diastolic velocity (E’) and peak late diastolic velocity (A’), were compared before and after HD. The WIWA measurements showed significant increases in W1 (p < 0.05) and preload-adjusted W1 (p < 0.01) after HD. W2 was significantly decreased (p < 0.05) after HD, whereas the change in preload-adjusted W2 was not significant. Systolic velocities, IVCV (p < 0.001) and PSV (p < 0.01), were increased after HD, whereas the AV-plane displacement were decreased (p < 0.01). For the measured diastolic variables, E’ was significantly decreased (p < 0.01) and IVRT was significantly prolonged (p < 0.05), after HD. A few correlations were found between WIWA and TVI variables. The WIWA and TVI measurements indicate that a single session of HD improves systolic function. The load dependency of the diastolic variables seems to be more pronounced than for the systolic variables. Preload-adjusted wave intensity indexes may contribute in the assessment of true LV contractility and relaxation.

  • 341.
    Bjällmark, Anna
    et al.
    KTH, Medicinsk teknik.
    Larsson, Matilda
    KTH, Medicinsk teknik.
    Shahgaldi, Kambiz
    Lind, Britta
    KTH, Skolan för teknik och hälsa (STH).
    Winter, Reidar
    Brodin, Lars-Ake
    KTH, Medicinsk teknik.
    Differences in myocardial velocities during supine and upright exercise stress echocardiography in healthy adults2009Inngår i: Clinical Physiology and Functional Imaging, ISSN 1475-0961, E-ISSN 1475-097X, Vol. 29, nr 3, s. 216-223Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Tissue Velocity Imaging (TVI) is a method for quantitative analysis of longitudinal myocardial velocities, which can be used during exercise and pharmacological stress echocardiography. It is of interest to evaluate cardiac response to different types of stress tests and the differences between upright and supine bicycle exercise tests have not been fully investigated. Therefore, the aim of this study was to compare cardiac response during supine and upright exercise stress tests. Twenty young healthy individuals underwent supine and upright stress test. The initial workload was set to 30 W and was increased every minute by a further 30 W until physical exhaustion. Tissue Doppler data from the left ventricle were acquired at the end of every workload level using a GE Vivid7 Dimension system (> 200 frames s(-1)). In the off-line processing, isovolumic contraction velocity (IVCV), peak systolic velocity (PSV), isovolumic relaxation velocity (IVRV), peak early diastolic velocity (E') and peak late diastolic velocity (A') were identified at every workload level. No significant difference between the tests was found in PSV. On the contrary, E' was shown to be significantly higher (P < 0.001) during supine exercise than during upright exercise and IVRV was significantly lower (P < 0.001) during supine exercise compared to upright exercise. Upright and supine exercise stress echocardiography give a comparable increase in measured systolic velocities and significant differences in early diastolic velocities.

  • 342.
    Bjällmark, Anna
    et al.
    KTH, Skolan för teknik och hälsa (STH), Medicinsk teknik.
    Larsson, Matilda
    KTH, Skolan för teknik och hälsa (STH), Medicinsk teknik.
    Shahgaldi, Kambiz
    Lind, Britta
    KTH, Skolan för teknik och hälsa (STH).
    Winter, Reidar
    Brodin, Lars-Ake
    KTH, Skolan för teknik och hälsa (STH), Medicinsk teknik.
    Differences in myocardial velocities during supine and upright exercise stress echocardiography in healthy adults2009Inngår i: Clinical Physiology and Functional Imaging, ISSN 1475-0961, E-ISSN 1475-097X, Vol. 29, nr 3, s. 216-223Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Tissue Velocity Imaging (TVI) is a method for quantitative analysis of longitudinal myocardial velocities, which can be used during exercise and pharmacological stress echocardiography. It is of interest to evaluate cardiac response to different types of stress tests and the differences between upright and supine bicycle exercise tests have not been fully investigated. Therefore, the aim of this study was to compare cardiac response during supine and upright exercise stress tests. Twenty young healthy individuals underwent supine and upright stress test. The initial workload was set to 30 W and was increased every minute by a further 30 W until physical exhaustion. Tissue Doppler data from the left ventricle were acquired at the end of every workload level using a GE Vivid7 Dimension system (> 200 frames s(-1)). In the off-line processing, isovolumic contraction velocity (IVCV), peak systolic velocity (PSV), isovolumic relaxation velocity (IVRV), peak early diastolic velocity (E') and peak late diastolic velocity (A') were identified at every workload level. No significant difference between the tests was found in PSV. On the contrary, E' was shown to be significantly higher (P < 0.001) during supine exercise than during upright exercise and IVRV was significantly lower (P < 0.001) during supine exercise compared to upright exercise. Upright and supine exercise stress echocardiography give a comparable increase in measured systolic velocities and significant differences in early diastolic velocities.

  • 343.
    Bjällmark, Anna
    et al.
    KTH, Medicinsk teknik.
    Lind, Britta
    KTH, Medicinsk teknik.
    Brodin, Lars-Åke
    KTH, Medicinsk teknik.
    Peolsson, Michael
    KTH, Skolan för teknik och hälsa (STH).
    Shahgaldi, Kambiz
    KTH, Medicinsk teknik.
    Nowak, Jacek
    Ultrasonographic strain imaging is superior to conventional non-invasive measures of vascular stiffness in the detection of age-dependent differences in the mechanical properties of the common carotid artery2010Inngår i: European Journal of Echocardiography, ISSN 1525-2167, E-ISSN 1532-2114, Vol. 11, nr 7, s. 630-636Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Aims: Elastic properties of large arteries have been shown to deteriorate with age and in the presence of atherosclerotic vascular disease. In this study, the performance of ultrasonographic strain measurements was compared to conventional measures of vascular stiffness in the detection of age-dependent differences in the elastic properties of the common carotid artery.

    Methods and results: In 10 younger (25-28 years, 4 women) and 10 older (50-59 years, 4 women) healthy individuals, global and regional circumferential and radial strain variables were measured in the short-axis view of the right common carotid artery using ultrasonographic two-dimensional (2D) strain imaging with recently introduced speckle tracking technique. Conventional elasticity variables, elastic modulus (Ep) and β stiffness index, were calculated using M-mode sonography and non-invasive blood pressure measurements. Global and regional circumferential systolic strain and strain rate values were significantly higher (p < 0.001, p < 0.01 for regional late systolic strain rate) in the younger individuals, whereas the values of conventional elasticity variables in the same group were lower (p < 0.05). Among all strain and conventional elasticity variables, principal component analysis and its regression extension identified only circumferential systolic strain variables as contributing significantly to the observed discrimination between the younger and older age groups.

    Conclusion: Ultrasonographic 2D-strain imaging is a sensitive method for the assessment of elastic properties in the common carotid artery, being in this respect superior to conventional measures of vascular elasticity. The method has potential to become a valuable non-invasive tool in the detection of early atherosclerotic vascular changes.

  • 344.
    Bjällmark, Anna
    et al.
    KTH, Skolan för teknik och hälsa (STH), Medicinsk teknik.
    Lind, Britta
    KTH, Skolan för teknik och hälsa (STH), Medicinsk teknik.
    Brodin, Lars-Åke
    KTH, Skolan för teknik och hälsa (STH), Medicinsk teknik.
    Peolsson, Michael
    KTH, Skolan för teknik och hälsa (STH).
    Shahgaldi, Kambiz
    KTH, Skolan för teknik och hälsa (STH), Medicinsk teknik.
    Nowak, Jacek
    Ultrasonographic strain imaging is superior to conventional non-invasive measures of vascular stiffness in the detection of age-dependent differences in the mechanical properties of the common carotid artery2010Inngår i: European Journal of Echocardiography, ISSN 1525-2167, E-ISSN 1532-2114, Vol. 11, nr 7, s. 630-636Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Aims: Elastic properties of large arteries have been shown to deteriorate with age and in the presence of atherosclerotic vascular disease. In this study, the performance of ultrasonographic strain measurements was compared to conventional measures of vascular stiffness in the detection of age-dependent differences in the elastic properties of the common carotid artery.

    Methods and results: In 10 younger (25-28 years, 4 women) and 10 older (50-59 years, 4 women) healthy individuals, global and regional circumferential and radial strain variables were measured in the short-axis view of the right common carotid artery using ultrasonographic two-dimensional (2D) strain imaging with recently introduced speckle tracking technique. Conventional elasticity variables, elastic modulus (Ep) and β stiffness index, were calculated using M-mode sonography and non-invasive blood pressure measurements. Global and regional circumferential systolic strain and strain rate values were significantly higher (p < 0.001, p < 0.01 for regional late systolic strain rate) in the younger individuals, whereas the values of conventional elasticity variables in the same group were lower (p < 0.05). Among all strain and conventional elasticity variables, principal component analysis and its regression extension identified only circumferential systolic strain variables as contributing significantly to the observed discrimination between the younger and older age groups.

    Conclusion: Ultrasonographic 2D-strain imaging is a sensitive method for the assessment of elastic properties in the common carotid artery, being in this respect superior to conventional measures of vascular elasticity. The method has potential to become a valuable non-invasive tool in the detection of early atherosclerotic vascular changes.

  • 345.
    Björkehag, Jonathan
    et al.
    Södertörns högskola, Institutionen för ekonomi och företagande.
    Seglare, Kristin
    Södertörns högskola, Institutionen för ekonomi och företagande.
    Innovationssystem för medicinsk teknik i Stockholm: En undersökning av centrala omständigheter för organisatorisk samverkan2009Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [en]

    Introduction In order to foster innovation of medical devices within the healthcare sector, a collaboration project, PUSH, has been initiated including the hospitals managed by the Stockholm County Council. The collaboration aims to capture ideas from employees and turn them into so called “high-practice” products as well as facilitate the possibilities for medical device companies to try out their products in the settings of healthcare. Collaborations for innovation, comparable to the PUSH project, can be found in both Swedish and foreign regions, but some of them fail to survive due to obstacles affecting the progress of each collaboration. Avoiding the same destiny will be a challenge to the PUSH project.

    Purpose The purpose is to search for factors affecting organizational collaboration concerning innovation systems for medical device development. The study is focusing on ”high-practice” products within the PUSH project.

    Theoretical approach In order to emphasize factors affecting innovation, theories regarding innovation systems, clusters and networks has been studied hence they  all concern organizational collaboration.

    Method The study’s qualitative approach is based on a semi deductive method. The analysis derives from a deductive outlook consistent with chosen theories, whereas collected data is used inductively to stress and enlarge part of the theoretical framework. Semi structured interviews, earlier research and evaluations constitutes most of the collected data.

    Results and analysis Experience from collaborations for innovation shows that some affecting factors can’t be influenced by collaborators, as political decisions and medical device directives. Collaborators can however affect circumstances such as connections and networking, which is significant to manage the innovation process; from idea to commercialization. An explicit focus on commercialization is important to the collaboration project’s surviving opportunities. A central cause why innovation projects don’t last is lack of funding, both for commercializing certain products as well as for retaining and developing existing innovation structures.

    Conclusion Collaborating projects should utilize existing structures and complement their networks to involve extensive competency. Decision makers need to decide whether innovation ventures shall be part of the County Council’s assignment. To fulfil the visions of the collaboration project, a policy common to all participants in the forthcoming innovation project needs to be stated, regarding ownership relations, risk sharing, funding and sharing of profits.

  • 346.
    Björkehag, Jonathan
    et al.
    Södertörns högskola, Institutionen för ekonomi och företagande.
    Seglare, Kristin
    Södertörns högskola, Institutionen för ekonomi och företagande.
    Karolinska Testbädd för Telemedicin och eHälsa: En analys av medicintekniska företags behov och krav på en samverkansmiljö för produktutveckling på Karolinska Universitetssjukhuset2010Independent thesis Advanced level (degree of Master (One Year)), 20 poäng / 30 hpOppgave
    Abstract [sv]

    Syftet med uppsatsen är att kartlägga behovet av en testbädd för telemedicinska produkter och att analysera krav som medicintekniska företag ställer på en testbäddsmiljö för samverkan med sjukvården. Målet har varit att konkretisera resultatet i en kommersialiseringsplan för Karolinska Testbädd för Telemedicin och eHälsa, vid Medicinsk Teknik på Karolinska Universitetssjukhuset. Vid genomförandet av undersökningen har totalt 19 intervjuer och ytterligare 6 telefonintervjuer genomförts med dels representanter från medicintekniska företag och sjukvården och dels med samarbetsstrukturer för medicinsk teknik och möjliga finansiärer. En enkätundersökning har genomförts för att kvantifiera resultatet från intervjuerna. Webbutskick har gjorts till 279 företag med verksamhet inom områdena medicinsk teknik, IT och telekom.

    Uppsatsen beskriver hur den kliniska forskningen inom området medicinsk teknik har förändrats de senaste decennierna och hur situationen ser ut idag. Utmaningar som den svenska hälso- och sjukvården står inför presenteras, som demografiska förändringar, ökade sjukvårdskostnader, dyrare behandlingsmetoder och färre kommersialiserade innovationer inom medicinsk teknik.  Omständigheter som påverkar produktutveckling för hälso- och sjukvården belyses, dels genom den regulatoriska gränsdragningen mellan IT-produkter och medicintekniska produkter och dels utifrån en genomgång av forskning inom produkt- och tjänsteutveckling och utifrån de frågor kring hur företag bedriver produktutveckling som ställts i intervjuerna och i webbenkäten.

    Resultatet visar att företagen i högsta grad är beroende av samarbete med sjukvården i olika faser av sin produktutvecklingsprocess och att flera företag uttrycker ett behov av en testbäddsstruktur. Företagen samarbetar med vården framförallt för att det möjliggör att utveckla mer vårdanpassade produkter. Samarbete med vården ger kortare utvecklingstider och därmed minskade utvecklingskostnader. Det förenklar även arbetet med validering av produkters funktionalitet. Flera företag har utarbetade samarbeten direkt in på vårdavdelningar, medan andra i dagsläget saknar nödvändiga samarbetsstrukturer. Studien har identifierat ett flertal företag som visat intresse för ett samarbete med Testbädden och ytterligare ett antal som har önskat att få mer information om vad Testbädden kan erbjuda. I kommersialiseringsplanen föreslås Karolinska Testbädd för Telemedicin och eHälsa fokusera på sin nisch samt vidareutveckla den kompetens som företagen saknar. Testbädden bör arbeta vidare med att utveckla både externa kontakter och den interna samverkansorganisationen på Karolinska för att möjliggöra effektiva, smidiga och kvalitativa samarbeten mellan företag och sjukhusets avdelningar.

  • 347.
    Björklund, Tomas
    KTH, Skolan för teknik och hälsa (STH).
    Automatic evaluation of breast density in mammographic images2012Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    The goal of this master thesis is to develop a computerized method for automatic estimation of the mammographic density of mammographic images from 5 different types of mammography units.

     

    Mammographic density is a measurement of the amount of fibroglandular tissue in a breast. This is the single most attributable risk factor for breast cancer; an accurate measurement of the mammographic density can increase the accuracy of cancer prediction in mammography. Today it is commonly estimated through visual inspection by a radiologist, which is subjective and results in inter-reader variation.

     

    The developed method estimates the density as a ratio of #pixels-containing-dense-tissue over #pixels-containing-any-breast-tissue and also according to the BI-RADS density categories. To achieve this, each mammographic image is:

    • corrected for breast thickness and normalized such that some global threshold can separate dense and non-dense tissue.
    • iteratively thresholded until a good threshold is found.  This process is monitored and automatically stopped by a classifier which is trained on sample segmentations using features based on different image intensity characteristics in specified image regions.
    • filtered to remove noise such as blood vessels from the segmentation.
    • Finally, the ratio of dense tissue is calculated and a BI-RADS density class is assigned based on a calibrated scale (after averaging the ratings of both craniocaudal images for each patient). The calibration is based on resulting density ratio estimations of over 1300 training samples against ratings by radiologists of the same images.

     

    The method was tested on craniocaudal images (not included in the training process) acquired with different mammography units of 703 patients which had also been rated by radiologists according to the BI-RADS density classes. The agreement with the radiologist rating in terms of Cohen’s weighted kappa is substantial (0.73). In 68% of the cases the agreement is exact, only in 1.2% of the cases the disagreement is more than 1 class.

  • 348.
    Björkman, Daniel
    et al.
    KTH, Skolan för teknik och hälsa (STH).
    Lundgren, Daniel
    Spårning av skelettala strukturer på 4D-CT2013Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [en]

    The technical development of computed tomography (CT) with faster image collection frequencies and lower radiation dose while maintaining or increasing spatial and tissue-specific resolution, has enabled timeresoluted dynamic CT for the study of body parts in motion.

     

    The development of this technology has come to the attention of the supervisors at the Karolinska Institute and the Royal Institute of Technology. They were interested to investigate the possibility of using today´s technology to calculate the kinematics of skeletal foot segments, based on a dynamic CT collection of a human foot. Thus a method to detect, extract and track landmarks in sequences of 3-dimensional (3D) volumes, and the description of foot kinematics during plantarflexion and dorsiflexion was developed in this thesis.

     

    The developed method intended to automatically track skeletal foot segments and calculate their relative movement and rotation in the frontal, sagittal and transverse plane. A program was developed using commercially available software that isolated a selected skeletal segment and detected its landmarks. The automatic landmark detection useful for tracking needs further development and therefore complementary manual detection was performed. These landmarks were used to calculate the kinematics by tracking individually created local coordinate system for each structure. As an example the maximum rotation stated between calcaneus and talus was 51 degrees within the sagittal plane. The thesis illustrates methods used and presents the developed program and all the results of the individual and relative motion of the calcaneus and talus. The method used in this thesis has a good future potential with possibilities to visualize and calculate normal and pathological musculoskeletal motion.

  • 349.
    Björkman, Simon
    Högskolan Kristianstad, Sektionen för lärande och miljö.
    Utveckling och optimering av en multiplex-PCR screen för högfrekventa humana trombocytantigen (HPA) alleler -1a, -2a, -3a, -5a, -15a och -15b med Extract-N-Amp Blood kit2017Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [sv]

    Det är känt att humant trombocytantigen (HPA) kan innebära komplikationer vid transfusion av trombocyter. Om en patient erhåller trombocyter med humant trombocytantigen som personen redan utvecklat antikroppar emot kan komplikationer som feber, påskyndad nedbrytning av trombocyter som ger trombocytopeni samt post-transfusion purpura uppstå eftersom immunförsvaret då ser trombocyterna som fientliga.

    Från den 14:e veckan under graviditeten kan alloantikroppar från modern passera placentabarriären över till fostret. Om humant trombocytantigen skiljer mellan moder och foster kan modern utveckla antikroppar. Dessa antikroppar kan då förstöra fostrets trombocyter. Detta leder till en lägre koncentration av trombocyter hos barnet. I värsta fall kan detta leda till hjärnblödning med dödlighet på ca.20%. Om barnet överlever födseln kommer denne födas med fetal/neonatal alloimmuniserad trombocytopeni (FNAIT), d.v.s. medfödd trombocytopeni.

    Målet med denna studie var att utveckla en multiplex PCR-screen, snabbt positivt/negativt svar för högfrekventa Humant trombocytantigen alleler baserat på de mest frekventa som förekommer i dansk befolkning: HPA 1a, -2a, -3a, -5a, -15a och -15b med Extract-N-AmpTMblood kit. Negativa prov från screening genomgick allelic discrimination real-tids PCR för konfirmering av sann HPA- genotyp.

    En lyckad multiplex screenmix innehållande HPA 1a, -2a, -5a samt -15a genomfördes. Då HPA - 3a bildade ospecifika band fick denna plockas bort ur mixen. För HPA 15b bildades ingen PCR- produkt och kunde därför inte inkluderas. Totalt screenades 44 blodgivare från Region Skåne varav fyra var negativa för 15a. Detta konfirmerades med allelic discrimination där dessa genotypades till 15b och i likhet med den multipla screeningen inte visade amplifiering av 15a. Vidare optimering krävs där nya primers för 3a samt 15b måste designas för att skapa en komplett högfrekvent human trombocytantigen screen. 

  • 350.
    Björneld, Olle
    Linköpings universitet, Institutionen för medicinsk teknik.
    Optisk instrument för Laparoskopisk Kärldetektion1996Independent thesis Advanced level (degree of Master (One Year)), 20 poäng / 30 hpOppgave
    Abstract [sv]

    Rapporten behandlar utvecklingen och konstruktionen av ett laparoskopiskt blodkärlsidentifierande instrument. Identifiering sker med hjälp av fotopletysmografi. Fotopletysmografi betyder ungefär "detektion av volymförändrings med hjälp av ljus". Laparoskopi kan översättas med titthålskirurgi. Laparoskopioperationer sker med små runda instrument som förs in i kroppen. Rapporten diskuterar olika probmodeller, det vill säga hur sensorn skall konstrueras för att erhålla en bra mätsignal. Konkurrerande tekniker och framtida applikationer redovisas på flera ställen i rapporten. Vid mätningar på blodmodell studerades och analyserades signalkvaliten. Till slut skall tilläggas att proben fungerade tillfredsställande. Proben kunde detektera pulsationer i blodmodellen.

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