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  • 201.
    Atefi, Seyed Reza
    et al.
    Harvard Univsersity.
    Seoane, Fernando
    Högskolan i Borås, Akademin för vård, arbetsliv och välfärd. KTH-School of Technology and Health.
    Kamalian, Shervin
    Rosenthal, Eric
    Lev, Michael
    Massachussets University Hospital.
    Bonmassar, Giorgio
    Harvard University.
    Intracranial haemorrhage alters scalp potential distributions in bioimpedance cerebral monitoring applications: preliminary results from FEM simulation on a realistic head model and human subjects2016Inngår i: Medical Physics, ISSN 0094-2405, Vol. 43, nr 2, s. 675-686Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Purpose:

    Current diagnostic neuroimaging for detection of intracranial hemorrhage (ICH) is limited to fixed scanners requiring patient transport and extensive infrastructure support. ICH diagnosis would therefore benefit from a portable diagnostic technology, such as electrical bioimpedance (EBI). Through simulations and patient observation, the authors assessed the influence of unilateral ICH hematomas on quasisymmetric scalp potential distributions in order to establish the feasibility of EBI technology as a potential tool for early diagnosis.

    Methods:

    Finite element method(FEM) simulations and experimental left–right hemispheric scalp potential differences of healthy and damaged brains were compared with respect to the asymmetry caused by ICH lesions on quasisymmetric scalp potential distributions. In numerical simulations, this asymmetry was measured at 25 kHz and visualized on the scalp as the normalized potential difference between the healthy and ICH damaged models. Proof-of-concept simulations were extended in a pilot study of experimental scalp potential measurements recorded between 0 and 50 kHz with the authors’ custom-made bioimpedance spectrometer. Mean left–right scalp potential differences recorded from the frontal, central, and parietal brain regions of ten healthy control and six patients suffering from acute/subacute ICH were compared. The observed differences were measured at the 5% level of significance using the two-sample Welch t-test.

    Results:

    The 3D-anatomically accurate FEM simulations showed that the normalized scalp potential difference between the damaged and healthy brainmodels is zero everywhere on the head surface, except in the vicinity of the lesion, where it can vary up to 5%. The authors’ preliminary experimental results also confirmed that the left–right scalp potential difference in patients with ICH (e.g., 64 mV) is significantly larger than in healthy subjects (e.g., 20.8 mV; P < 0.05).

    Conclusions:

    Realistic, proof-of-concept simulations confirmed that ICH affects quasisymmetric scalp potential distributions. Pilot clinical observations with the authors’ custom-made bioimpedance spectrometer also showed higher left–right potential differences in the presence of ICH, similar to those of their simulations, that may help to distinguish healthy subjects from ICH patients. Although these pilot clinical observations are in agreement with the computer simulations, the small sample size of this study lacks statistical power to exclude the influence of other possible confounders such as age, sex, and electrode positioning. The agreement with previously published simulation-based and clinical results, however, suggests that EBI technology may be potentially useful for ICH detection.

  • 202.
    Atefi, Seyed Reza
    et al.
    KTH, Skolan för teknik och hälsa (STH), Medicinsk teknik, Medicinska sensorer, signaler och system.
    Seoane, Fernando
    KTH, Skolan för teknik och hälsa (STH), Medicinsk teknik, Medicinska sensorer, signaler och system.
    Kamalian, Shervin
    Rosenthal, Eric
    Lev, Michael
    Bonmassar, Giorgio
    Intracranial haemorrhage alters scalp potential distributions in bioimpedance cerebral monitoring applications: preliminary results from FEM simulation on a realistic head model and human subjects2016Inngår i: Medical Physics, ISSN 2473-4209, Vol. 43, nr 2, s. 675-686Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Purpose: Current diagnostic neuroimaging for detection of intracranial hemorrhage (ICH) is limited to fixed scanners requiring patient transport and extensive infrastructure support. ICH diagnosis would therefore benefit from a portable diagnostic technology, such as electrical bioimpedance (EBI). Through simulations and patient observation, the authors assessed the influence of unilateral ICH hematomas on quasisymmetric scalp potential distributions in order to establish the feasibility of EBI technology as a potential tool for early diagnosis. Methods: Finite element method (FEM) simulations and experimental leftright hemispheric scalp potential differences of healthy and damaged brains were compared with respect to the asymmetry caused by ICH lesions on quasisymmetric scalp potential distributions. In numerical simulations, this asymmetry was measured at 25 kHz and visualized on the scalp as the normalized potential difference between the healthy and ICH damaged models. Proof-of-concept simulations were extended in a pilot study of experimental scalp potential measurements recorded between 0 and 50 kHz with the authors custom-made bioimpedance spectrometer. Mean leftright scalp potential differences recorded from the frontal, central, and parietal brain regions of ten healthy control and six patients suffering from acute/subacute ICH were compared. The observed differences were measured at the 5% level of significance using the two-sample Welch ttest. Results: The 3D-anatomically accurate FEM simulations showed that the normalized scalp potential difference between the damaged and healthy brain models is zero everywhere on the head surface, except in the vicinity of the lesion, where it can vary up to 5%. The authors preliminary experimental results also confirmed that the leftright scalp potential difference in patients with ICH (e.g., 64 mV) is significantly larger than in healthy subjects (e.g., 20.8 mV; P < 0.05). Conclusions: Realistic, proof-of-concept simulations confirmed that ICH affects quasisymmetric scalp potential distributions. Pilot clinical observations with the authors custom-made bioimpedance spectrometer also showed higher leftright potential differences in the presence of ICH, similar to those of their simulations, that may help to distinguish healthy subjects from ICH patients. Although these pilot clinical observations are in agreement with the computer simulations, the small sample size of this study lacks statistical power to exclude the influence of other possible confounders such as age, ex, and electrode positioning. The agreement with previously published simulation-based and clinical results, however, suggests that EBI technology may be potentially useful for ICH detection. © 2016 American Association of Physicists in Medicine.

  • 203.
    Atefi, Seyed Reza
    et al.
    KTH, Skolan för teknik och hälsa (STH), Medicinska sensorer, signaler och system (MSSS).
    Seoane, Fernando
    KTH, Skolan för teknik och hälsa (STH), Medicinska sensorer, signaler och system (MSSS).
    Lindecrantz, Kaj
    KTH, Skolan för teknik och hälsa (STH), Medicinska sensorer, signaler och system (MSSS).
    Electrical Bioimpedance cerebral monitoring. Preliminary results from measurements on stroke patients2012Inngår i: Engineering in Medicine and Biology Society (EMBC), 2012 Annual International Conference of the IEEE, IEEE , 2012, s. 126-129Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Electrical Bioimpedance Spectroscopy (EBIS) is currently used in different tissue characterization applications. In this work we aim to use EBIS to study changes in electrical properties of the cerebral tissues after an incident of hemorrhage/ischemic stroke. To do so a case-control study was conducted using six controls and three stroke cases. The preliminary results of this study show that by using Cole-based analysis on EBIS measurements and analyzing the Cole parameters R0 and R∞, it is possible to detect changes on electrical properties of cerebral tissue after stroke. 

  • 204.
    Atefi, Seyed Reza
    et al.
    KTH, Skolan för teknik och hälsa (STH), Medicinsk teknik, Medicinska sensorer, signaler och system.
    Seoane, Fernando
    KTH, Skolan för teknik och hälsa (STH), Medicinsk teknik, Medicinska sensorer, signaler och system.
    Lindecrantz, Kaj
    KTH, Skolan för teknik och hälsa (STH), Medicinsk teknik, Medicinska sensorer, signaler och system.
    Study of the dynamics of transcephalic cerebral impedance data during cardio-vascular surgery2013Inngår i: XV International Conference on Electrical Bio-Impedance (ICEBI) & XIV Conference on Electrical Impedance Tomography (EIT), Institute of Physics (IOP), 2013, Vol. 434, nr 1, s. 012045-Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Postoperative neurological deficits are one of the risks associated with cardio vascular surgery, necessitating development of new techniques for cerebral monitoring. In this study an experimental observation regarding the dynamics of transcephalic Electrical Bioimpedance (EBI) in patients undergoing cardiac surgery with and without extracorporeal circulation (ECC) was conducted to investigate the potential use of electrical Bioimpedance for cerebral monitoring in cardio vascular surgery. Tetrapolar transcephalic EBI measurements at single frequency of 50 kHz were recorded prior to and during cardio vascular surgery. The obtained results show that the transcephalic impedance decreases in both groups of patients as operation starts, however slight differences in these two groups were also observed with the cerebral impedance reduction in patients having no ECC being less common and not as pronounced as in the ECC group. Changes in the cerebral impedance were in agreement with changes of haematocrit and temperature. The origin of EBI changes is still unexplained however these results encourage us to continue investigating the application of electrical bioimpedance cerebral monitoring clinically.

  • 205.
    Atefi, Seyed Reza
    et al.
    KTH, Skolan för teknik och hälsa (STH), Medicinsk teknik, Medicinska sensorer, signaler och system.
    Seoane, Fernando
    KTH, Skolan för teknik och hälsa (STH), Medicinsk teknik, Medicinska sensorer, signaler och system.
    Thorlin, Thorleif
    Lindecrantz, Kaj
    KTH, Skolan för teknik och hälsa (STH), Medicinsk teknik, Medicinska sensorer, signaler och system.
    Stroke Damage Detection Using Classification Trees on Electrical Bioimpedance Cerebral Spectroscopy Measurements2013Inngår i: Sensors, ISSN 1424-8220, E-ISSN 1424-8220, Vol. 13, nr 8, s. 10074-10086Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    After cancer and cardio-vascular disease, stroke is the third greatest cause of death worldwide. Given the limitations of the current imaging technologies used for stroke diagnosis, the need for portable non-invasive and less expensive diagnostic tools is crucial. Previous studies have suggested that electrical bioimpedance (EBI) measurements from the head might contain useful clinical information related to changes produced in the cerebral tissue after the onset of stroke. In this study, we recorded 720 EBI Spectroscopy (EBIS) measurements from two different head regions of 18 hemispheres of nine subjects. Three of these subjects had suffered a unilateral haemorrhagic stroke. A number of features based on structural and intrinsic frequency-dependent properties of the cerebral tissue were extracted. These features were then fed into a classification tree. The results show that a full classification of damaged and undamaged cerebral tissue was achieved after three hierarchical classification steps. Lastly, the performance of the classification tree was assessed using Leave-One-Out Cross Validation (LOO-CV). Despite the fact that the results of this study are limited to a small database, and the observations obtained must be verified further with a larger cohort of patients, these findings confirm that EBI measurements contain useful information for assessing on the health of brain tissue after stroke and supports the hypothesis that classification features based on Cole parameters, spectral information and the geometry of EBIS measurements are useful to differentiate between healthy and stroke damaged brain tissue.

  • 206.
    Atefi, Seyed Reza
    et al.
    Harvard University.
    Seoane, Fernando
    Högskolan i Borås, Akademin för vård, arbetsliv och välfärd. KTH-School of Technology and Health.
    Thorlin, Thorleif
    salhgrenska Hospital.
    Lindecrantz, Kaj
    KTH-School of Technology and Health.
    Stroke Damage Detection Using Classification Trees on Electrical Bioimpedance Cerebral Spectroscopy Measurements2013Inngår i: Sensors, ISSN 1424-8220, E-ISSN 1424-8220, Vol. 13, nr 8, s. 10074-10086Artikkel i tidsskrift (Fagfellevurdert)
  • 207.
    Athanasiou, Vasileios
    Linköpings universitet, Institutionen för medicin och hälsa, Avdelningen för radiologiska vetenskaper. Linköpings universitet, Hälsouniversitetet.
    Estimation and modelling of fMRI BOLD response2014Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    One of the current topics of research in neuroimaging techniques is related to explaining and modelling the Blood Oxygen Level Dependent (BOLD) responses. BOLD responses are estimated by processing functional Magnetic Resonance Imaging (fMRI) data. BOLD responses are caused by hemodynamic responses to neural activity which alter the levels of blood oxygenation at local brain regions. The main aims of the current thesis were to i) develop and examine methods regarding BOLD response estimation from the visual cortex and the frontal cortex of human brain and to ii) develop a model in order to explain the physiological mechanisms which cause the estimated BOLD responses.

    In order to satisfy the main aims, fMRI data were provided by the Center of Medical Imaging and Visualization (CMIV). The provided fMRI data consist of fMRI brain measurements of twelve healthy human subjects who were subjected to visual stimulation. By processing the fMRI data, Regions Of Interest (ROIs) were extracted at the anatomical sites of the visual cortex and the frontal cortex. Afterwards, the fMRI data were manipulated in order to extract BOLD responses from the visual cortex and the frontal cortex. Various methods were developed and compared in terms of which technique provided well representative BOLD responses.       

    Subsequently, a model was developed by using software Wolfram Mathematica 9 in order to explain the physiological mechanisms of the estimated BOLD responses at the visual and the frontal cortex. The model aimed to solve for oxygen concentration in blood plasma as blood flows from the arterial part to the venous part of the blood circulation system through a capillary. Oxygen outward diffusion through the capillary wall and oxygen concentration at the extravascular environment were modelled as well. Blood plasma oxygen concentration was turned into hemoglobin oxygen saturation (Sa ) through hemoglobin oxygen dissociation curve and Henry’s law for gases. As a result, the Sa  was estimated through modelling for oxygen concentration in blood plasma. Finally, the developed model ended to a system with input the fractional change of Cerebral Blood Flow (CBF) velocity and Cerebral Metabolic Rate of Oxygen (CMR ) and as output a proportional signal to the BOLD response. By simulating for different scenarios of fractional changes of CBF velocity and CMR  and by comparing the resulted BOLD responses to the estimated ones, it was attempted to explain for the physiological mechanisms which caused the BOLD responses at the anatomical sites of the visual and frontal cortex.

  • 208.
    Auer, Martin
    et al.
    Develoment, Vascops GmbH, Graz, Austria.
    Gasser, Thomas Christian
    KTH, Skolan för teknikvetenskap (SCI), Hållfasthetslära (Inst.), Biomekanik.
    Portugaller, R.
    Automatic Displacement and Strain measuring in the Aorta from dynamic electrocardiographically-gated Computed Tomographic Angiography2010Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Introduction

    Image modalities like Duplex Ultrasound, Transesophageal Echocardiography, Intravascular Ultrasound, Computed Tomography and Magnetic Resonance provide vascular interventionists and surgeons with useful diagnostic information for treatment planning. Recent developments in cross-sectional imaging, including multi-modality image fusion and new contrast agents have resulted in improved spatial resolution. Specifically, dynamic Electrocardiographically-Gated Computed Tomographic Angiography (ECG-gated CTA) provides valuable information regarding motion and deformation of the normal and diseased aorta during the cardiac cycle. Extracting and presenting (visualization) of accurate quantitative information from the recorded image data, however remains a challenging task of image post processing.

    Method

    The algorithm proposed within this paper processes ECG-gated CTA data (here goes the scanner model and manufacturer) in DICOM (digital imaging and communication in medicine) format, within which the user manually defines an Eulerian Region of Interest (ROI). 2D deformable (active) contour models are used to pre-segment the luminal surfaces of the selected vessels at an arbitrary time point during the cardiac cycle. A tessellation algorithm is used to define the initial configuration of a 3D deformable (active) contour model, which in turn is used for the final segmentation of the luminal surfaces continuously during the cardiac cycle. Specifically, Finite Element (FE) formulations [1] for frames and shells, as known from structural mechanics, are used to define the deformable contour modes. This allows a direct mechanical interpretation of the applied set of reconstruction parameters and leads to an efficient FE implementation of the models [2]; parallel processor architecture is used to solve the global set of non-linear FE equations. Finally displacement and strain measures are derived from the dynamic segmentations and color coded plots are used to visualize them.

    Results and Conclusions

    The clinical relevance of dynamic imaging has not been fully exploited and accurate and fast image processing tools are critical to extract valuable information from ECG-gated CTA data. Such information is not only of direct clinical relevance but also critical to process our current understanding regarding normal and pathological aortic motions and deformations. The image processing concept proposed in this paper leads to efficient and clinically applicable software that facilitates an analysis of the entire aorta on a standard Personal Computer within a few minutes. Deformable (active) contour models are known to be more accurate compared to threshold based segmentation concepts [3] and the accuracy of the present approach is in the range of the in-plane image resolution. Apart from direct diagnostic information the extracted geometrical data could also be used (once enriched by accurate pressure measurements) for none invasive (minimal invasive) estimation of biomechanical aortic tissue properties.

    References

    [1] O. C. Zienkiewicz and R. L. Taylor, vol.1,2, 5th ed. Oxford: Butterworth Heinemann, 2000.

    [2] M. Auer and T. C. Gasser,

    IEEE T. Med. Imaging, 2010 (in press).

    [3] M. Sonka and J. M. Fitzpatrick, editors.,

    Bellingham: Spie press, 2000

  • 209.
    Augustine, Robin
    Uppsala University.
    A Non-invasive Skin Burn Degree Analysis Using Microwaves2015Konferansepaper (Annet vitenskapelig)
  • 210.
    Augustine, Robin
    Uppsala University.
    A Preliminary Study on Skin Burn Degree Analysis Based on Coupling Effect between Burn Area and Micro Strip Ring Resonator2016Konferansepaper (Fagfellevurdert)
  • 211.
    Augustine, Robin
    Uppsala University.
    Application of UWB Radar Techniques for Imaging cranial vaults2015Konferansepaper (Annet vitenskapelig)
  • 212. Augustine, Robin
    Arrowroot (Maranta arundinacea) is an edible starch, commercially available as powder, prepared from the roots of the plant family Marantaceae. Arrowroot is well known for its medicinal effects and use as chief ingredient in infant cookies. Arrowroot in film form is prepared and its microwave absorption characteristics, permittivity, loss factor, conductivity, skin depth, and heating coefficient are analyzed. The results are quite promising and can be concluded that arrowroot in film form is a potential candidate for several applications in medical field, when compared with well studied chitosan film2009Inngår i: Microwave and Optical Technology Letters, Vol. 51, nr 5Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Arrowroot (Maranta arundinacea) is an edible starch, commercially available as powder, prepared from the roots of the plant family Marantaceae. Arrowroot is well known for its medicinal effects and use as chief ingredient in infant cookies. Arrowroot in film form is prepared and its microwave absorption characteristics, permittivity, loss factor, conductivity, skin depth, and heating coefficient are analyzed. The results are quite promising and can be concluded that arrowroot in film form is a potential candidate for several applications in medical field, when compared with well studied chitosan film

  • 213. Augustine, Robin
    Biocompatibility study of beta tricalcium phosphate bioceramics and chitosan biopolymer and their use as phantoms for medical imaging applications2009Inngår i: Microwave and Optical Technology Letters, Vol. 51, nr 12Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Beta tricalcium phosphate (b-TCP) bioceramics and chitosan biopolymers are used as biomedical implants because of their better biocompatibility and good bioresorption characteristics. As they are biomaterials, they have good interactions with microwave frequencies. b-TCP and chitosan powder, films, pellets, and gel are prepared and studied at the S-band microwave frequencies. Dielectric parameters such as dielectric constant, dielectric loss, conductivity, and S-parameters are evaluated. Dielectric parameters of different forms of b-TCP and chitosan show resemblance with that of human tissues. Hence, these materials can also be considered as potential phantoms for specific absorption rate measurements as well as in microwave imaging applications. V

  • 214. Augustine, Robin
    Biocompatibility study of hydroxyapatite-chitosan composite for medical applications at microwave frequencies2008Inngår i: Microwave and optical technology letters (Print), ISSN 0895-2477, E-ISSN 1098-2760, Vol. 50, nr 11, s. 2931-2934Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Hydroxyapatite (HAp, Ca10(PO4)6(OH)2) bioceramic and chitosan (poly [(β-1-4) d-glucosamine]) biopolymer show good biocompatibility in vivo. They have biological origin and show excellent interactions with microwave. Microwave study of HAp made using different drying techniques and their composites with chitosan in the ISM band is presented. Pastes are made using HAp and chitosan with different ratios of mixing. The dielectric properties of this composites match with that of human fat, collagen tissues. Some of the compositions exhibit dielectric property close to that of natural bone. This makes them more biocompatible and better substitutes for natural bone. Thus composite bioceramics can be considered as phantom model constituents for imaging purposes.

  • 215. Augustine, Robin
    Chitosan Biopolymer for Microwave Tomography Applications2008Konferansepaper (Fagfellevurdert)
  • 216. Augustine, Robin
    Complex dielectric permittivity measurements of human skin and biological solution in2-67GHz range2012Konferansepaper (Fagfellevurdert)
  • 217.
    Augustine, Robin
    Uppsala University.
    COmplex Fracture Orthopedic RehabiliTation – COMFORT2016Konferansepaper (Fagfellevurdert)
  • 218.
    Augustine, Robin
    Uppsala University.
    Experimental procedure for determination of the dielectric properties of biological samples in the 2-50 GHz range2014Inngår i: IEEE Journal of Translational Engineering in Health and Medicine, E-ISSN 2168-2372Artikkel i tidsskrift (Fagfellevurdert)
  • 219. Augustine, Robin
    Human skin permittivity models for the millimeter-wave range2011Inngår i: IET Electronics Letters, Vol. 47, s. 427-428Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The complex permittivity of the human skin has been measured in vivo in the 10 –60 GHz range using a recently developed coaxial slim probe. The results are compared with the literature data at millimetre waves, and a broad-band Cole-Cole model is proposed for several locations on the arm, namely at the palm, wrist, and forearm. This reported study provides relevant data required for studying interactions between emerging body-centric wireless millimetre-wave technologies and the human body

  • 220.
    Augustine, Robin
    Uppsala University.
    Microwave antenna for analysis of mineralization in cranial vaults2015Konferansepaper (Annet vitenskapelig)
  • 221.
    Augustine, Robin
    Uppsala University.
    Microwave head phantoms for post-craniotomy and BMP based implant2015Konferansepaper (Annet vitenskapelig)
  • 222.
    Augustine, Robin
    Uppsala University.
    Microwave studies on Beta Tricalcium Phosphate Bioceramics for medical application2006Konferansepaper (Fagfellevurdert)
  • 223.
    Augustine, Robin
    Uppsala University.
    Monitoring weight bearing in an ambulant setting: the SensiStep2016Konferansepaper (Fagfellevurdert)
  • 224. Augustine, Robin
    Near-field dosimetry for the millimeter-wave exposure of human cells in vitro2012Inngår i: Bioelectromagnetics, ISSN 0197-8462, E-ISSN 1521-186X, s. 55-64Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Due to the expected mass deployment of millimeter-wave wireless technologies, thresholds of potential millimeter-wave-induced biological and health effects should be carefully assessed. The main purpose of this study is to propose, optimize, and characterize a near-field exposure configuration allowing illumination of cells in vitro at 60 GHz with power densities up to several tens of mW/cm(2) . Positioning of a tissue culture plate containing cells has been optimized in the near-field of a standard horn antenna operating at 60 GHz. The optimal position corresponds to the maximal mean-to-peak specific absorption rate (SAR) ratio over the cell monolayer, allowing the achievement of power densities up to 50 mW/cm(2) at least. Three complementary parameters have been determined and analyzed for the exposed cells, namely the power density, SAR, and temperature dynamics. The incident power density and SAR have been computed using the finite-difference time-domain (FDTD) method. The temperature dynamics at different locations inside the culture medium are measured and analyzed for various power densities. Local SAR, determined based on the initial rate of temperature rise, is in a good agreement with the computed SAR (maximal difference of 5%). For the optimized exposure setup configuration, 73% of cells are located within the ±3 dB region with respect to the average SAR. It is shown that under the considered exposure conditions, the maximal power density, local SAR, and temperature increments equal 57 mW/cm(2) , 1.4 kW/kg, and 6 °C, respectively, for the radiated power of 425 mW.

  • 225.
    Augustine, Robin
    Uppsala University.
    Phantom models for human hip and thigh2016Konferansepaper (Fagfellevurdert)
  • 226. Augustine, Robin
    Polymeric ferrite sheets for SAR reduction of wearable antennas2010Inngår i: IET Electronics letters, Vol. 46, nr 3, s. 197-199Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Reduction of specific absorption rate (SAR) has now become a buzz word because of the growing health concerns over microwave exposure. Ferrites are found to be effective in diminishing electromagnetic influence. In this reported work, flexible polymeric ferrite sheets are characterised on the basis of their shielding efficiencies. SAR measurements are carried out with a planar wearable antenna and polymeric ferrite shielding to confirm its competence.

  • 227. Augustine, Robin
    Polymeric ferrite-loaded antennas for on-body communications2009Inngår i: Microwave and Optical technology Letters, Vol. 51, nr 11Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Wearable antennas are integral part of body area networks (BANs). Antenna design for BAN applications is a challenging task since the antennas have to be small, efficient, and must not be affected by the wearer's body. This makes isolation of antenna a matter of importance. Ferrites form an opaque media for microwave at the 2.4-GHz ISM band and hence it could be used for the isolation of antenna from surroundings. Thin polymeric ferrite sheets are used to reduce body influence in BAN perspective.

  • 228.
    Augustine, Robin
    Uppsala University.
    SRR Antenna for Biomedical Application2016Konferansepaper (Fagfellevurdert)
  • 229.
    Augustine, Robin
    Uppsala University.
    Transverse Electromagnetic cell for Biological cell exposure studies Sujith2016Konferansepaper (Fagfellevurdert)
  • 230.
    Augustine, Robin
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Kurup, Dhanesh G.
    Amrita Vishva Vidyapeetham Univ, Dept Elect & Commun, Bangalore, Karnataka, India.
    Raman, Sujith
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Lee, Dujin
    Gwangju Inst Sci & Technol, Dept Med Syst Engn, Gwangju, South Korea.
    Kim, K. Kangwook
    Gwangju Inst Sci & Technol, Sch Informat & Mechatron, Gwangju, South Korea.
    Rydberg, Anders
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Bone Mineral Density Analysis using Ultra Wideband Microwave Measurements2015Konferansepaper (Fagfellevurdert)
    Abstract [en]

    A novel approach to analyze the bone mineral density (BMD) based on microwave reflectivity analysis is presented in this paper. The proposed method enables us to overcome the health risks associated with diagnostic techniques such as X-rays for repeated study of the rate of mineralization in the case of fractures or de-mineralization in the case of osteoporosis. In this paper, we demonstrate the application of Microwaves for continuous observation of skull healing process during post-cranial surgery period. The proposed technique can be a potential clinical model in future for extracting target characteristics such as bone deposition thickness and other cranial defects. Based on the conclusions of wideband measured data, we propose to design the Transceiver using ultra wideband (UWB) pulsed technology.

  • 231. Ausen, Dag
    et al.
    Westvik, Rita
    Svagård, Ingrid
    Österlund, Lars
    Gustafson, Inga
    Vikholm-Lundin, Inger
    Winquist, Fredrik
    Lading, Lars
    Gran, Jens
    Foresight Biomedical Sensors2007Rapport (Annet vitenskapelig)
    Abstract [en]

    The foresight study on biomedical sensors has addressed different approaches with future use of biomedical sensors in the health care sector, like: How will biomedical sensors shape the healthcare systems of the future? How can they impact the quality and cost of healthcare and what are the business opportunities in the Nordic region?

  • 232.
    Avenel, Christophe
    et al.
    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.
    Carlbom, Ingrid
    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.
    Blur detection and visualization in histological whole slide images2015Inngår i: Proc. 10th International Conference on Mass Data Analysis of Images and Signals, Leipzig, Germany: IBaI , 2015Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Digital pathology holds the promise of improved workflow and also of the use of image analysis to extract features from tissue samples for quantitative analysis to improve current subjective analysis of, for example, cancer tissue. But this requires fast and reliable image digitization. In this paper we address image blurriness, which is a particular problem with very large images or tissue micro arrays scanned with whole slide scanners, since autofocus methods may fail when there is a large variation in image content. We introduce a method to detect, quantify and dis-play blurriness from whole slide images (WSI) in real-time. We describe a blurriness measurement based on an ideal high pass filter in the frequency domain. In contrast with other method our method does not require any prior knowledge of the image content, and it produces a continuous blurriness map over the entire WSI. This map can be displayed as an overlay of the original data and viewed at different levels of magnification with zoom and pan features. The computation time for an entire WSI is around 5 minutes on an average workstation, which is about 180 times faster than existing methods.

  • 233.
    Axelson, Mattias
    Linköpings universitet, Institutionen för medicinsk teknik.
    A Physiological investigation of Rest in Commercial Long-Haul Truck Drivers2018Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
  • 234.
    Axelsson, Jan
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Radiofysik.
    Imlook4d: introducing an extendable research 4d analysis software2014Inngår i: XII Turku PET Symposium, 24-27 May 2014, Turku, Finland: the symposium of Nordic Association for Clinical Physics (NACP), 2014, s. 63-63Konferansepaper (Annet vitenskapelig)
    Abstract [en]

    Imlook4d (http://www.dicom-port.com) is a free Matlab based graphical user interface (GUI) tool useful for static, dynamic and gated PET studies.  It supports reading and writing DICOM, Nifti, Analyze, ECAT.  The DICOM reader is orders of magnitude faster than the Matlab imaging toolbox.  Imlook4d requires no additional Matlab toolboxes.

    The main benefit with imlook4d is that it is easily extendable with scripts, accessing exported variables such as the image matrix (4D) and a region-of-interest (ROI) matrix.  Scripts are available via a menu in the imlook4d GUI, and can be used to manipulate the image-matrix and ROI data.  There is also a menu option to export and import these variables to the Matlab workspace for interactive manipulation, useful for one-off fixes or for script development.  There are presently about 30 scripts in categories such as ROI, Matrix, Header info etc.  There is also direct export to ImageJ [1] and import back from ImageJ, thus giving access to all tools available within ImageJ.

    Imlook4d has a built in volume-of-interest editor, with a brush tool for quick interactive ROI delineation, and via scripts, different ways of thresholding ROIs from parts of the image.  Time activity data is saved to a tab-delimited text file.

    The principal-component (PC) based Hotelling filter is an integrated part of the program, which allows for interactive noise reduction without loss of quantitation [2].  A typical work flow for a dynamic data set is to turn on the filter for ROI delineation, and then there is the choice of turning it off for export of time-activity data.  Also the PC images can be used to draw ROIs on, which under some circumstances gives enhanced contrast.

    Calculation of parametric pharmacokinetic modelling images can be performed interactively, calculated slice by slice as the user scrolls through the volume.  Reference models for Patlak, Logan and Averaged Simple Flow Model [3]  applied on 15O-water are implemented, and it is relatively easy to implement other kinetic models.  Similarly, scripts have been developed for regional Patlak and Logan models on ROI data.

    [1] Rasband, WS, ImageJ, U. S. National Institutes of Health, Bethesda, Maryland, USA, http://imagej.nih.gov/ij/, 1997-2014

    [2] Axelsson J, Sörensen J, The 2D Hotelling filter - a quantitative noise-reducing principal-component filter for dynamic PET data, with applications in patient dose reduction. BMC Med Phys. 2013 Apr 10;13:1. doi: 10.1186/1756-6649-13-1.

    [3] Yoshida, K, Mullani, N and Gould KL, Coronary Flow and Flow Reserve by PET Simplified for Clinical Applications Using Rubidium-82 or Nitrogen-13-Ammonia, J Nucl Med 1996; 37:1701-1712

    Figure 1.  The imlook4d GUI with the user SCRIPTS menu selected.  The group of ROI scripts was further selected.  In the underlying image, a rough ROI is created.  

  • 235.
    Axelsson, Jan
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Radiofysik.
    Sörensen, Jens
    PET-center, Department of Radiology, Oncology and Radiation Sciences, Uppsala University, Uppsala, Sweden.
    The 2D Hotelling filter: a quantitativenoise-reducing principal-component filter fordynamic PET data, with applications in patientdose reduction2013Inngår i: BMC Medical Physics, ISSN 1756-6649, Vol. 13, nr 1Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Background: In this paper we apply the principal-component analysis filter (Hotelling filter) to reduce noise fromdynamic positron-emission tomography (PET) patient data, for a number of different radio-tracer molecules. Wefurthermore show how preprocessing images with this filter improves parametric images created from suchdynamic sequence.We use zero-mean unit variance normalization, prior to performing a Hotelling filter on the slices of a dynamictime-series. The Scree-plot technique was used to determine which principal components to be rejected in thefilter process. This filter was applied to [11C]-acetate on heart and head-neck tumors, [18F]-FDG on liver tumors andbrain, and [11C]-Raclopride on brain. Simulations of blood and tissue regions with noise properties matched to realPET data, was used to analyze how quantitation and resolution is affected by the Hotelling filter. Summing varyingparts of a 90-frame [18F]-FDG brain scan, we created 9-frame dynamic scans with image statistics comparable to 20MBq, 60 MBq and 200 MBq injected activity. Hotelling filter performed on slices (2D) and on volumes (3D) werecompared.Results: The 2D Hotelling filter reduces noise in the tissue uptake drastically, so that it becomes simple to manuallypick out regions-of-interest from noisy data. 2D Hotelling filter introduces less bias than 3D Hotelling filter in focalRaclopride uptake. Simulations show that the Hotelling filter is sensitive to typical blood peak in PET prior to tissueuptake have commenced, introducing a negative bias in early tissue uptake. Quantitation on real dynamic data isreliable. Two examples clearly show that pre-filtering the dynamic sequence with the Hotelling filter prior toPatlak-slope calculations gives clearly improved parametric image quality. We also show that a dramatic dosereduction can be achieved for Patlak slope images without changing image quality or quantitation.Conclusions: The 2D Hotelling-filtering of dynamic PET data is a computer-efficient method that gives visuallyimproved differentiation of different tissues, which we have observed improve manual or automated regionof-interest delineation of dynamic data. Parametric Patlak images on Hotelling-filtered data display improved clarity,compared to non-filtered Patlak slope images without measurable loss of quantitation, and allow a dramaticdecrease in patient injected dose.

  • 236.
    Axelsson, Pelle
    et al.
    KTH, Skolan för teknik och hälsa (STH).
    Torelm, Marcus
    KTH, Skolan för teknik och hälsa (STH).
    Cost-benefit-analys av optisk 3D-scanner2011Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
  • 237. Ayllnon, David
    et al.
    Gil-Pita, Roberto
    Seoane, Fernando
    KTH, Skolan för teknik och hälsa (STH), Medicinsk teknik, Medicinska sensorer, signaler och system.
    Detection and Classification of Measurement Errors in Bioimpedance Spectroscopy2016Inngår i: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 11, nr 6, artikkel-id e0156522Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Bioimpedance spectroscopy (BIS) measurement errors may be caused by parasitic stray capacitance, impedance mismatch, cross-talking or their very likely combination. An accurate detection and identification is of extreme importance for further analysis because in some cases and for some applications, certain measurement artifacts can be corrected, minimized or even avoided. In this paper we present a robust method to detect the presence of measurement artifacts and identify what kind of measurement error is present in BIS measurements. The method is based on supervised machine learning and uses a novel set of generalist features for measurement characterization in different immittance planes. Experimental validation has been carried out using a database of complex spectra BIS measurements obtained from different BIS applications and containing six different types of errors, as well as error-free measurements. The method obtained a low classification error (0.33%) and has shown good generalization. Since both the features and the classification schema are relatively simple, the implementation of this pre-processing task in the current hardware of bioimpedance spectrometers is possible.

  • 238.
    Ayllon, David
    et al.
    Universidad de Alcalá.
    Gil-Pita, Roberto
    Universidad de Alcalá.
    Seoane, Fernando
    Högskolan i Borås, Akademin för textil, teknik och ekonomi. KTH-School of Technology and Health.
    Detection and Classification of Measurement Errors in Bioimpedance Spectroscopy2016Inngår i: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 11, nr 6, artikkel-id e0156522Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Bioimpedance spectroscopy (BIS) measurement errors may be caused by parasitic stray capacitance, impedance mismatch, cross-talking or their very likely combination. An accurate detection and identification is of extreme importance for further analysis because in some cases and for some applications, certain measurement artifacts can be corrected, minimized or even avoided. In this paper we present a robust method to detect the presence of measurement artifacts and identify what kind of measurement error is present in BIS measurements. The method is based on supervised machine learning and uses a novel set of generalist features for measurement characterization in different immittance planes. Experimental validation has been carried out using a database of complex spectra BIS measurements obtained from different BIS applications and containing six different types of errors, as well as error-free measurements. The method obtained a low classification error (0.33%) and has shown good generalization. Since both the features and the classification schema are relatively simple, the implementation of this pre-processing task in the current hardware of bioimpedance spectrometers is possible.

  • 239.
    Ayllon, David
    et al.
    Department of Signal Theory and Communications.
    Seoane, Fernando
    KTH, Skolan för teknik och hälsa (STH), Medicinska sensorer, signaler och system (MSSS).
    Gil-Pita, Roberto
    Department of Signal Theory and Communications.
    Cole equation and parameter estimation from electrical bioimpedance spectroscopy measurements: A comparative study2009Inngår i: EMBC: 2009 ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY, VOLS 1-20, Buenos Aires: IEEE Engineering in Medicine and Biology , 2009, s. 3779-3782Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Since there are several applications of Electrical Bioimpedance (EBI) that use the Cole parameters as base of the analysis, to fit EBI measured data onto the Cole equation is a very common practice within Multifrequency-EBI and spectroscopy. The aim of this paper is to compare different fitting methods for EBI data in order to evaluate their suitability to fit the Cole equation and estimate the Cole parameters. Three of the studied fittings are based on the use of Non-Linear Least Squares on the Cole model, one using the real part only, a second using the imaginary part and the third using the complex impedance. Furthermore, a novel fitting method done on the impedance plane, without using any frequency information has been implemented and included in the comparison. Results show that the four methods perform relatively well but the best fitting in terms of standard error of estimate is the fitting obtained from the resistance only. The results support the possibility of measuring only the resistive part of the bioimpedance to accurately fit Cole equation and estimate the Cole parameters, with entailed advantages.

  • 240. Azar, J.C.
    et al.
    Hamid Muhammed, Hamed
    KTH, Skolan för teknik och hälsa (STH), Medicinsk teknik.
    Automated Tracking of the Carotid Artery in Ultrasound Image Sequences Using a Self Organizing Neural Network2010Inngår i: Proceedings of 20th International Conference on Pattern Recognition (ICPR 2010), Istanbul, Turkey, Istanbul, Turkey, 2010, s. 2548-2551Konferansepaper (Fagfellevurdert)
    Abstract [en]

    An automated method for the segmentation and tracking of moving vessel walls in 2D ultrasound image sequences is introduced. The method was tested on simulated and real ultrasound image sequences of the carotid artery. Tracking was achieved via a self organizing neural network known as Growing Neural Gas. This topology-preserving algorithm assigns a net of nodes connected by edges that distributes itself within the vessel walls and adapts to changes in topology with time. The movement of the nodes was analyzed to uncover the dynamics of the vessel wall. By this way, radial and longitudinal strain and strain rates have been estimated. Finally, wave intensity signals were computed from these measurements. The method proposed improves upon wave intensity wall analysis, WIWA, and opens up a possibility for easy and efficient analysis and diagnosis of vascular disease through noninvasive ultrasonic examination.

  • 241.
    Azar, Jimmy
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Bildanalys och människa-datorinteraktion. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Avdelningen för visuell information och interaktion.
    Automated Tissue Image Analysis Using Pattern Recognition2014Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Automated tissue image analysis aims to develop algorithms for a variety of histological applications. This has important implications in the diagnostic grading of cancer such as in breast and prostate tissue, as well as in the quantification of prognostic and predictive biomarkers that may help assess the risk of recurrence and the responsiveness of tumors to endocrine therapy.

    In this thesis, we use pattern recognition and image analysis techniques to solve several problems relating to histopathology and immunohistochemistry applications. In particular, we present a new method for the detection and localization of tissue microarray cores in an automated manner and compare it against conventional approaches.

    We also present an unsupervised method for color decomposition based on modeling the image formation process while taking into account acquisition noise. The method is unsupervised and is able to overcome the limitation of specifying absorption spectra for the stains that require separation. This is done by estimating reference colors through fitting a Gaussian mixture model trained using expectation-maximization.

    Another important factor in histopathology is the choice of stain, though it often goes unnoticed. Stain color combinations determine the extent of overlap between chromaticity clusters in color space, and this intrinsic overlap sets a main limitation on the performance of classification methods, regardless of their nature or complexity. In this thesis, we present a framework for optimizing the selection of histological stains in a manner that is aligned with the final objective of automation, rather than visual analysis.

    Immunohistochemistry can facilitate the quantification of biomarkers such as estrogen, progesterone, and the human epidermal growth factor 2 receptors, in addition to Ki-67 proteins that are associated with cell growth and proliferation. As an application, we propose a method for the identification of paired antibodies based on correlating probability maps of immunostaining patterns across adjacent tissue sections.

    Finally, we present a new feature descriptor for characterizing glandular structure and tissue architecture, which form an important component of Gleason and tubule-based Elston grading. The method is based on defining shape-preserving, neighborhood annuli around lumen regions and gathering quantitative and spatial data concerning the various tissue-types.

  • 242.
    Azar, Jimmy
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Bildanalys och människa-datorinteraktion.
    Busch, Christer
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för immunologi, genetik och patologi, Molekylär och morfologisk patologi.
    Carlbom, Ingrid
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Bildanalys och människa-datorinteraktion.
    Histological Stain Evaluation for Machine Learning Applications2012Inngår i: Proceedings of the International Conference on Medical Image Computing and Computer Assisted Intervention, 2012Konferansepaper (Fagfellevurdert)
  • 243.
    Azar, Jimmy
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Bildanalys och människa-datorinteraktion.
    Busch, Christer
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för genetik och patologi.
    Carlbom, Ingrid
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Bildanalys och människa-datorinteraktion.
    Microarray Core Detection by Geometric Restoration2012Inngår i: Analytical Cellular Pathology, ISSN 0921-8912, E-ISSN 1878-3651, Vol. 35, nr 5-6, s. 381-393Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Whole-slide imaging of tissue microarrays (TMAs) holds the promise of automated image analysis of a large number of histopathological samples from a single slide. This demands high-throughput image processing to enable analysis of these tissue samples for diagnosis of cancer and other conditions. In this paper, we present a completely automated method for the accurate detection and localization of tissue cores that is based on geometric restoration of the core shapes without placing any assumptions on grid geometry. The method relies on hierarchical clustering in conjunction with the Davies-Bouldin index for cluster validation in order to estimate the number of cores in the image wherefrom we estimate the core radius and refine this estimate using morphological granulometry. The final stage of the algorithm reconstructs circular discs from core sections such that these discs cover the entire region of each core regardless of the precise shape of the core. The results show that the proposed method is able to reconstruct core locations without any evidence of localization error. Furthermore, the algorithm is more efficient than existing methods based on the Hough transform for circle detection. The algorithm's simplicity, accuracy, and computational efficiency allow for automated high-throughput analysis of microarray images.

  • 244.
    Azar, Jimmy C.
    et al.
    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.
    Simonsson, Martin
    Bengtsson, Ewert
    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.
    Hast, Anders
    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.
    Image segmentation and identification of paired antibodies in breast tissue2014Inngår i: Computational & Mathematical Methods in Medicine, ISSN 1748-670X, E-ISSN 1748-6718, s. 647273:1-11Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Comparing staining patterns of paired antibodies designed towards a specific protein but toward different epitopes of the protein provides quality control over the binding and the antibodies' ability to identify the target protein correctly and exclusively. We present a method for automated quantification of immunostaining patterns for antibodies in breast tissue using the Human Protein Atlas database. In such tissue, dark brown dye 3,3'-diaminobenzidine is used as an antibody-specific stain whereas the blue dye hematoxylin is used as a counterstain. The proposed method is based on clustering and relative scaling of features following principal component analysis. Our method is able (1) to accurately segment and identify staining patterns and quantify the amount of staining and (2) to detect paired antibodies by correlating the segmentation results among different cases. Moreover, the method is simple, operating in a low-dimensional feature space, and computationally efficient which makes it suitable for high-throughput processing of tissue microarrays.

  • 245.
    Azar, Jimmy
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Bildanalys och människa-datorinteraktion.
    Simonsson, Martin
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Bildanalys och människa-datorinteraktion.
    Bengtsson, Ewert
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Bildanalys och människa-datorinteraktion.
    Hast, Anders
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Bildanalys och människa-datorinteraktion.
    Automated Classification of Glandular Tissue by Statistical Proximity Sampling2015Inngår i: International Journal of Biomedical Imaging, ISSN 1687-4188, E-ISSN 1687-4196, artikkel-id 943104Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Due to the complexity of biological tissue and variations in staining procedures, features that are based on the explicit extraction of properties from subglandular structures in tissue images may have difficulty generalizing well over an unrestricted set of images and staining variations. We circumvent this problem by an implicit representation that is both robust and highly descriptive, especially when combined with a multiple instance learning approach to image classification. The new feature method is able to describe tissue architecture based on glandular structure. It is based on statistically representing the relative distribution of tissue components around lumen regions, while preserving spatial and quantitative information, as a basis for diagnosing and analyzing different areas within an image. We demonstrate the efficacy of the method in extracting discriminative features for obtaining high classification rates for tubular formation in both healthy and cancerous tissue, which is an important component in Gleason and tubule-based Elston grading. The proposed method may be used for glandular classification, also in other tissue types, in addition to general applicability as a region-based feature descriptor in image analysis where the image represents a bag with a certain label (or grade) and the region-based feature vectors represent instances.

  • 246. Azimi, I.
    et al.
    Anzanpour, A.
    Rahmani, A. M.
    Liljeberg, P.
    Tenhunen, Hannu
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Industriell och Medicinsk Elektronik.
    Self-aware early warning score system for IoT-based personalized healthcare2017Inngår i: International Summit on eHealth 360°, 2016, Springer, 2017, s. 49-55Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Early Warning Score (EWS) system is specified to detect and predict patient deterioration in hospitals. This is achievable via monitoring patient's vital signs continuously and is often manually done with paper and pen. However, because of the constraints in healthcare resources and the high hospital costs, the patient might not be hospitalized for the whole period of the treatments, which has lead to a demand for in-home or portable EWS systems. Such a personalized EWS system needs to monitor the patient at anytime and anywhere even when the patient is carrying out daily activities. In this paper, we propose a self-aware EWS system which is the reinforced version of the existing EWS systems by using the Internet of Things technologies and the self-awareness concept. Our self-aware approach provides (i) system adaptivity with respect to various situations and (ii) system personalization by paying attention to critical parameters. We evaluate the proposed EWS system using a full system demonstration. © ICST Institute for Computer Sciences, Social Informatics and Telecommunications Engineering 2017.

  • 247.
    Azzouzi, Sawsen
    et al.
    University of Sousse, Tunisia.
    Patra, Hirak Kumar
    Linköpings universitet, Institutionen för klinisk och experimentell medicin, Avdelningen för cellbiologi. Linköpings universitet, Medicinska fakulteten.
    Ben Ali, Mounir
    University of Sousse, Tunisia.
    Nooredeen Abbas, Mohammed
    National Research Centre, Egypt.
    Dridi, Cherif
    Centre Research Microelect and Nanotechnol CRMN Sousse, Tunisia.
    Errachid, Abdelhamid
    University of Lyon 1, France.
    Turner, Anthony
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biosensorer och bioelektronik. Linköpings universitet, Tekniska fakulteten.
    Citrate-selective electrochemical mu-sensor for early stage detection of prostate cancer2016Inngår i: Sensors and actuators. B, Chemical, ISSN 0925-4005, E-ISSN 1873-3077, Vol. 228, s. 335-346Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The extremely specialised anatomical function of citrate inside the prostate, make it one of the preferred biomarkers for early stage detection of prostate cancer. However, current detection methods are seriously limited due to the very low citrate concentrations that need to be measured in order to follow disease progression. In the present work, we report a novel citrate-selective-sensor based on iron (III) phthalocyanine chloride-C-monoamido-Poly-n-Butyl Acrylate (Fe(III)MAPcC1 P n BA) modified gold -electrodes for the electrochemical determination and estimation of the pathophysiological range of citrate. The newly synthesised ionophore has been structurally characterised using Fourier transform infrared (FTIR) and UV-vis spectroscopy. Contact angle measurements and atomic force microscopy (AFM) have been used to investigate the adhesion and morphological properties of the membrane. The developed citrate-selective-electrodes had a Nernstian sensitivity of-19.34 +/- 0.83 mV/decade with a detection limit of about 9 x 10-6M and a linear range from 4 x 10(-5)M to 10(-1) M, which covered the pathologically important clinical range. Electrochemical impedance spectroscopy (EIS) showed very high sensitivity with a lower Limit of detection 1.7 x 10(-9) M and linear detection range (10(-8)-10(-1) M), which is very important not only for the early-stage diagnosis and screening procedures, but also in mapping the stage of the cancer too. (C) 2016 Elsevier B.V. All rights reserved.

  • 248.
    Babic, Ankica
    Linköpings universitet, Institutionen för medicinsk teknik, Medicinsk informatik. Linköpings universitet, Tekniska högskolan. University of Bergen, Norway.
    Case Based Reasoningin Support of the LVAD Surgical Treatment2013Inngår i: Medicinteknikdagarna 2013, Electronic Proceedings, 2013Konferansepaper (Fagfellevurdert)
  • 249.
    Babic, Ankica
    et al.
    Linköpings universitet, Institutionen för medicinsk teknik, Medicinsk informatik. Linköpings universitet, Tekniska högskolan. University of Bergen, Norway.
    Peterzen, Bengt
    Östergötlands Läns Landsting, Hjärt- och Medicincentrum.
    Lönn, Urban
    Östergötlands Läns Landsting, Hjärt- och Medicincentrum.
    Casimir Ahn, Henrik
    Linköpings universitet, Institutionen för medicin och hälsa, Avdelningen för kardiovaskulär medicin. Linköpings universitet, Hälsouniversitetet. Östergötlands Läns Landsting, Hjärt- och Medicincentrum, Thorax-kärlkliniken i Östergötland.
    Case Based Reasoning in a Web Based Decision Support System for Thoracic Surgery2013Inngår i: IFMBE Proceedings 41 / [ed] L.M. Roa Romero, Springer, 2013, s. 1413-1416Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Case Based Reasoning (CBR) methodology provides means of collecting patients cases and retrieving them following the clinical criteria. By studying previously treated patients with similar backgrounds, the physician can get a better base for deciding on treatment for a current patient and be better prepared for complications that might occur during and after surgery. This could be taken advantage of when there is not enough data for a statistical analysis, but electronic patient records that provide all the relevant information to assure a timely and accurate clinical insight into a patient particular situation.

    We have developed and implemented a CBR engine using the Nearest Neighbor algorithm. A patient case is represented as a combination of perioperative variable values and operation reports. Physicians could review a selected number of cases by browsing through the electronic patient record and operational narratives which provides an exhaustive insight into the previously treated cases. An evaluation of the search algorithm suggests a very good functionality.

  • 250.
    Babic, Ankica
    et al.
    Linköpings universitet, Institutionen för medicinsk teknik, Medicinsk informatik. Linköpings universitet, Tekniska högskolan. University of Bergen, Norway.
    Soerheim, Helen
    University of Bergen, Norway.
    M-Health ApplicationProduct Development for Physiological Disorders Based on Interaction Design2013Inngår i: Medicinteknikdagarna 2013, Electronic Proceedings, 2013Konferansepaper (Fagfellevurdert)
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