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Maxantalet träffar du kan exportera från sökgränssnittet är 250. Vid större uttag använd dig av utsökningar.
  • 3001.
    Wårdell, Karin
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för medicinsk teknik, Biomedicinsk instrumentteknik.
    Biomedical Optics in Neurosurgery2013Ingår i: Biophotonics - Riga: 1st International Conference, Abstracts, University of Latvia Press, 2013Konferensbidrag (Refereegranskat)
  • 3002.
    Wårdell, Karin
    Linköpings universitet, Institutionen för medicinsk teknik.
    Clinical Applications in Functional Neuroscience2016Konferensbidrag (Refereegranskat)
  • 3003.
    Wårdell, Karin
    Linköpings universitet, Institutionen för medicinsk teknik.
    EAMBES fellows and recognition of excellence on BME2016Konferensbidrag (Refereegranskat)
  • 3004.
    Wårdell, Karin
    Linköpings universitet, Institutionen för medicinsk teknik, Biomedicinsk instrumentteknik. Linköpings universitet, Tekniska högskolan.
    Experience from optical measurements during 100 DBS implantations2012Konferensbidrag (Övrigt vetenskapligt)
  • 3005.
    Wårdell, Karin
    Linköpings universitet, Institutionen för medicinsk teknik, Avdelningen för medicinsk teknik. Linköpings universitet, Tekniska fakulteten.
    Fibre based optical techniques for guidance during stereotactic neurosurgery: a review2017Konferensbidrag (Övrigt vetenskapligt)
  • 3006.
    Wårdell, Karin
    Linköpings universitet, Institutionen för medicinsk teknik, Biomedicinsk instrumentteknik. Linköpings universitet, Tekniska högskolan.
    Neuro-engineering for Navigation, Intervention and Implementation in Neurosurgery (oral)2010Konferensbidrag (Refereegranskat)
  • 3007.
    Wårdell, Karin
    Linköpings universitet, Institutionen för medicinsk teknik, Biomedicinsk instrumentteknik. Linköpings universitet, Tekniska högskolan.
    Optical methods for intracerebral DBS navigation (oral, invited)2010Konferensbidrag (Refereegranskat)
  • 3008.
    Wårdell, Karin
    Linköpings universitet, Institutionen för medicinsk teknik, Avdelningen för medicinsk teknik. Linköpings universitet, Tekniska fakulteten.
    Optical Techniques for Monitoring in Neurosurgery2017Konferensbidrag (Refereegranskat)
  • 3009.
    Wårdell, Karin
    Linköpings universitet, Institutionen för medicinsk teknik, Biomedicinsk instrumentteknik. Linköpings universitet, Tekniska högskolan.
    Patient-specific electric field simulation for DBS - examples from Tourette syndrome2014Konferensbidrag (Övrigt vetenskapligt)
  • 3010.
    Wårdell, Karin
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för medicinsk teknik, Biomedicinsk instrumentteknik.
    Patient-specific simulation of DBS in the investigation of speech and movement, 3rd International Basal Ganglia Speech Disorder and Deep Brain Stimulation2014Konferensbidrag (Övrigt vetenskapligt)
  • 3011.
    Wårdell, Karin
    Linköpings universitet, Institutionen för medicinsk teknik, Biomedicinsk instrumentteknik. Linköpings universitet, Tekniska högskolan.
    Patient-Specific Simulations of DBS in the Investigation of Speech and Movement2014Konferensbidrag (Övrigt vetenskapligt)
  • 3012.
    Wårdell, Karin
    et al.
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för medicinsk teknik, Biomedicinsk instrumentteknik.
    Alonso, Fabiola
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för medicinsk teknik, Biomedicinsk instrumentteknik.
    Computational Finite Element Model to Compare Voltage and Current Controlled Deep Brain Stimulation Systems2013Konferensbidrag (Refereegranskat)
  • 3013.
    Wårdell, Karin
    et al.
    Linköpings universitet, Institutionen för medicinsk teknik, Biomedicinsk instrumentteknik. Linköpings universitet, Tekniska högskolan.
    Braverman, I.M.
    Silverman, D.G.
    Nilsson, Gert
    Linköpings universitet, Institutionen för medicinsk teknik, Biomedicinsk instrumentteknik. Linköpings universitet, Tekniska högskolan.
    Spatial heterogeity in normal skin perfusion recorded with laser Doppler imaging and flowmetry1994Ingår i: Microvascular Research, ISSN 0026-2862, E-ISSN 1095-9319, Vol. 48, nr 1, s. 26-38Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Spatial and temporal variations in forearm skin perfusion captured by laser Doppler perfusion imaging (LDI) have been compared with topographic maps recorded by laser Doppler flowmetry. In order to determine the shortest LDI sampling time required at each measurement site, with an adequate signal-to-noise ratio and with the ability to display the heterogeneity in skin perfusion, the noise-limited resolution of the LDI system as well as various sampling times were tested. The noise-limited resolution for medium and high light intensities were less than 0.5% (temporal) and 0.3% (spatial) of full scale. A sampling time of 1 sec was selected and image presentation was made by performing bilinear interpolation between perfusion values. The same area (10 x 10 mm) was mapped with LDI and topographic mapping at seven different sites. In addition, a larger area covering the surrounding skin was recorded with LDI. The small area recordings with LDI and topographic mapping could be identified in the larger LDI image. High-and low-perfusion spots coincided between the two systems. Temporal variations were studied by repeated LDI recordings of the same areas as above. Small spots were selected in the areas and plotted versus time. Without provocation, the total perfusion changes at each spot showed large variations, but the relative perfusion levels between neighboring spots persisted. Provocation with heat increased the perfusion in all spots.

  • 3014.
    Wårdell, Karin
    et al.
    Linköpings universitet, Institutionen för medicinsk teknik, Biomedicinsk instrumentteknik. Linköpings universitet, Tekniska högskolan.
    Diczfalusy, Elin
    Linköpings universitet, Institutionen för medicinsk teknik, Biomedicinsk instrumentteknik. Linköpings universitet, Tekniska högskolan.
    Andersson, Mats
    Linköpings universitet, Institutionen för medicinsk teknik, Biomedicinsk instrumentteknik. Linköpings universitet, Institutionen för medicinsk teknik, Medicinsk informatik. Linköpings universitet, Tekniska högskolan.
    Åström, Mattias
    Linköpings universitet, Institutionen för medicinsk teknik, Biomedicinsk instrumentteknik. Linköpings universitet, Tekniska högskolan.
    Foltynie, Thomas
    University College London, UK.
    Limousine, Patricia
    University College London, UK.
    Zrinzo, Ludwig
    University College London, UK.
    Hariz, Marwan
    University College London, UK.
    Patient-specific visualization of the DBS-electric field in Tourette syndrome2012Konferensbidrag (Övrigt vetenskapligt)
  • 3015.
    Wårdell, Karin
    et al.
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för medicinsk teknik, Biomedicinsk instrumentteknik.
    Diczfalusy, Elin
    Linköpings universitet, Institutionen för medicinsk teknik, Biomedicinsk instrumentteknik. Linköpings universitet, Tekniska högskolan.
    Åström, Mattias
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för medicinsk teknik, Biomedicinsk instrumentteknik. Sapiens Steering Brain Stimulation B.V., The Netherlands .
    Patient-Specific Modeling and Simulation of Deep Brain Stimulation2011Ingår i: Patient-Specific Modeling in Tomorrow's Medicine / [ed] Amit Gefen, Springer Berlin/Heidelberg, 2011, s. 357-378Kapitel i bok, del av antologi (Refereegranskat)
    Abstract [en]

    Deep brain stimulation (DBS) is widely used for reduction of symptoms caused by movement disorders. In this chapter a patient-specific finite element method for modeling and simulation of DBS electric parameters is presented. The individual’s stereotactic preoperative MR-batch of images is used as input to the model in order to classify tissue type and allot electrical conductivity for cerebrospinal fluid, blood and grey as well as white matter. With patient-specific positioning of the DBS electrodes the method allows for investigation of the relative electric field changes in relation to anatomy and DBS-settings. Examples of visualization of the patient-specific electric entities together with the surrounding anatomy are given. The use of the method is exemplified on patients with Parkinson’s disease. Future applications including multiphysics simulations and applicability for new DBS targets and symptoms are discussed.

  • 3016.
    Wårdell, Karin
    et al.
    Linköpings universitet, Institutionen för medicinsk teknik, Biomedicinsk instrumentteknik. Linköpings universitet, Tekniska högskolan.
    Diczfalusy, Elin
    Linköpings universitet, Institutionen för medicinsk teknik, Biomedicinsk instrumentteknik. Linköpings universitet, Tekniska högskolan.
    Åström, Mattias
    Linköpings universitet, Institutionen för medicinsk teknik, Biomedicinsk instrumentteknik. Linköpings universitet, Tekniska högskolan.
    Software for patient specific simulation and visualization of electric field around deep brain stimulation electrodes (electronic poster)2011Konferensbidrag (Refereegranskat)
  • 3017.
    Wårdell, Karin
    et al.
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för medicinsk teknik, Biomedicinsk instrumentteknik.
    Diczfalusy, Elin
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för medicinsk teknik, Biomedicinsk instrumentteknik.
    Åström, Mattias
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för medicinsk teknik, Biomedicinsk instrumentteknik. Sapiens Steering Brain Stimulation B.V., The Netherlands .
    Martens, Hubert
    2Sapiens Steering Brain Stimulation B.V., The Netherlands.
    Deep Brain Stimulation: Electric Field as a Predictor of Neural Activation2013Konferensbidrag (Refereegranskat)
  • 3018.
    Wårdell, Karin
    et al.
    Linköpings universitet, Institutionen för medicinsk teknik, Biomedicinsk instrumentteknik. Linköpings universitet, Tekniska högskolan.
    Eklund, Anders
    Dept. of Biomedical Engineering, Umeå University Hospital, Sweden.
    Neuro-engineering (oral)2010Konferensbidrag (Övrigt vetenskapligt)
  • 3019.
    Wårdell, Karin
    et al.
    Linköpings universitet, Institutionen för medicinsk teknik, Biomedicinsk instrumentteknik. Linköpings universitet, Tekniska högskolan.
    Eriksson, O.
    Linköpings universitet, Institutionen för medicinsk teknik, Biomedicinsk instrumentteknik. Linköpings universitet, Tekniska högskolan.
    Nilsson, Gert
    Linköpings universitet, Institutionen för medicinsk teknik, Biomedicinsk instrumentteknik.
    Anordning för kontrollerat förstörande av vävnad.2003Patent (Övrig (populärvetenskap, debatt, mm))
  • 3020.
    Wårdell, Karin
    et al.
    Linköpings universitet, Institutionen för medicinsk teknik, Biomedicinsk instrumentteknik. Linköpings universitet, Tekniska högskolan.
    Eriksson, O.
    Linköpings universitet, Institutionen för medicinsk teknik, Biomedicinsk instrumentteknik. Linköpings universitet, Tekniska högskolan.
    Nilsson, Gert
    Linköpings universitet, Institutionen för medicinsk teknik, Biomedicinsk instrumentteknik.
    Anordning för kontrollerat förstörande av vävnad.2003Patent (Övrig (populärvetenskap, debatt, mm))
  • 3021.
    Wårdell, Karin
    et al.
    Linköpings universitet, Institutionen för medicinsk teknik, Biomedicinsk instrumentteknik. Linköpings universitet, Tekniska högskolan.
    Eriksson, O.
    Linköpings universitet, Institutionen för medicinsk teknik, Biomedicinsk instrumentteknik. Linköpings universitet, Tekniska högskolan.
    Nilsson, Gert
    Linköpings universitet, Institutionen för medicinsk teknik, Biomedicinsk instrumentteknik.
    Anordning för kontrollerat förstörande av vävnad.2006Patent (Övrig (populärvetenskap, debatt, mm))
  • 3022.
    Wårdell, Karin
    et al.
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för medicinsk teknik, Biomedicinsk instrumentteknik.
    Haj-Hosseini, Neda
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för medicinsk teknik, Biomedicinsk instrumentteknik.
    Hemm-Ode, Simone
    Linköpings universitet, Institutionen för medicinsk teknik, Biomedicinsk instrumentteknik. Linköpings universitet, Tekniska högskolan. Institute for Medical and Analytical Technologies, University of Applied Sciences and Art Northwestern Switzerland, Basel.
    Comparison between Optical and MRI Trajectories in Stereotactic Neurosurgery2014Ingår i: XIII Mediterranean Conference on Medical and Biological Engineering and Computing 2013 : MEDICON 2013, 25 - 28 September 2013, Seville, Spain / [ed] Laura M. Roa Romero, 2014, s. 49-51Konferensbidrag (Refereegranskat)
    Abstract [en]

    Deep brain stimulation (DBS) is an effective treatment for movement disorders e.g. Parkinson's disease. Thin electrodes are implanted into the deep brain structures by means of stereotactic technique and electrical stimulations are delivered to the brain tissue. Accuracy and safety during the implantation is important for optimal stimulation effect and minimization of bleedings. In addition to microelectrode recording and impedance measurements, intraoperative optical measurements using laser Doppler perfusion monitoring (LDPM) have previously been suggested as guidance tool during stereotactic DBS implantations. In this study we compare optical trajectories, recorded with LDPM ranging from cortex towards the subthalamic nucleus (STN), to the corresponding magnetic resonance imaging (MRI) trajectories. Inversed gray scales from the T2-weighted MRI were used for comparison with the total light intensity (TLI) representing tissue grayness. Both curves followed a general tendency with a deep dip in the vicinity to the left ventricle. MRI trajectories might help in predicting the optical trajectory but further studies including more data and fine tuning of the comparative methodology are required

  • 3023.
    Wårdell, Karin
    et al.
    Linköpings universitet, Institutionen för medicinsk teknik, Biomedicinsk instrumentteknik. Linköpings universitet, Tekniska högskolan. Linköpings universitet, Centrum för medicinsk bildvetenskap och visualisering, CMIV.
    Hemm-Ode, Simone
    Linköpings universitet, Institutionen för medicinsk teknik, Biomedicinsk instrumentteknik. Linköpings universitet, Tekniska högskolan. Institute for Medical and Analytical Technologies, University of Applied Sciences and Art Northwestern Switzerland, Basel.
    Optical and microvascular measurements for guidance during DBS implantation2014Konferensbidrag (Övrigt vetenskapligt)
  • 3024.
    Wårdell, Karin
    et al.
    Linköpings universitet, Institutionen för medicinsk teknik. Linköpings universitet, Centrum för medicinsk bildvetenskap och visualisering, CMIV.
    Hemm-Ode, Simone
    Linköpings universitet, Institutionen för medicinsk teknik. Institute for Medical and Analytical Technologies and Department of Biomedical Engineering, University of Applied Sciences and Art Northwestern Switzerland .
    Zsigmond, Peter
    Region Östergötland, Sinnescentrum, Neurokirurgiska kliniken US. Linköpings universitet, Institutionen för klinisk och experimentell medicin, Avdelningen för neuro- och inflammationsvetenskap.
    Fibre optical probe navigation during deep brain stimulation, implantation – safety aspects2016Konferensbidrag (Refereegranskat)
  • 3025.
    Wårdell, Karin
    et al.
    Linköpings universitet, Institutionen för medicinsk teknik. Linköpings universitet, Centrum för medicinsk bildvetenskap och visualisering, CMIV.
    Hemm-Ode, Simone
    Linköpings universitet, Institutionen för medicinsk teknik. Institute for Medical and Analytical Technologies and Department of Biomedical Engineering, University of Applied Sciences and Art Northwestern Switzerland .
    Zsigmond, Peter
    Region Östergötland, Sinnescentrum, Neurokirurgiska kliniken US. Linköpings universitet, Institutionen för klinisk och experimentell medicin, Avdelningen för neuro- och inflammationsvetenskap.
    Laser Doppler Flowmetry Guidance during Stereotactic Neurosurgery: A Review of Safety Aspects2016Konferensbidrag (Refereegranskat)
  • 3026.
    Wårdell, Karin
    et al.
    Linköpings universitet, Institutionen för medicinsk teknik, Biomedicinsk instrumentteknik. Linköpings universitet, Tekniska högskolan.
    Jakobsson, A.
    Nilsson, Gert
    Linköpings universitet, Institutionen för medicinsk teknik, Biomedicinsk instrumentteknik. Linköpings universitet, Tekniska högskolan.
    Laser Doppler Perfusion Imaging by Dynamic Light Scattering1993Ingår i: IEEE Transactions on Biomedical Engineering, ISSN 0018-9294, E-ISSN 1558-2531, Vol. 40, nr 4, s. 309-316Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A laser Doppler perfusion imaging technique based on dynamic light scattering in tissue is reported. When a laser beam sequentially scans the tissue (maximal area approximately 12 cm*12 cm), moving blood cells generate Doppler components in the backscattered light. A fraction of this light is detected by a remote photodiode and converted into an electrical signal. In the signal processor, a signal proportional to the tissue perfusion at each measurement point is calculated and stored. When the scanning procedure is completed, the system generates a color-coded perfusion image on a monitor. A perfusion image is typically built up of data from 4096 measurement sites, recorded during a time period of 4 min. This image has a spatial resolution of about 2 mm. A theory for the system inherent amplification factor dependence on the distance between individual measurement points and detector is proposed and correction measures are presented. Performance results for the laser Doppler perfusion imager obtained with a flow simulator are presented. The advantages of the method are discussed.

  • 3027.
    Wårdell, Karin
    et al.
    Linköpings universitet, Institutionen för medicinsk teknik, Biomedicinsk instrumentteknik. Linköpings universitet, Tekniska högskolan.
    Johansson, Johannes
    Linköpings universitet, Institutionen för medicinsk teknik, Biomedicinsk instrumentteknik. Linköpings universitet, Tekniska högskolan.
    A System for Optical Guidance during Stereotactic Neurosurgery (oral)2010Konferensbidrag (Refereegranskat)
  • 3028.
    Wårdell, Karin
    et al.
    Linköpings universitet, Institutionen för medicinsk teknik, Avdelningen för medicinsk teknik. Linköpings universitet, Tekniska fakulteten.
    Johansson, Johannes
    Linköpings universitet, Institutionen för medicinsk teknik, Avdelningen för medicinsk teknik. Linköpings universitet, Tekniska fakulteten.
    Alonso, Fabiola
    Linköpings universitet, Institutionen för medicinsk teknik, Avdelningen för medicinsk teknik. Linköpings universitet, Tekniska fakulteten.
    Deep brain stimulation: software for patient-specific electric field simulations2017Konferensbidrag (Refereegranskat)
    Abstract [en]

    Introduction

    The electric field (EF) around the active deep brain stimulation (DBS) contact is of interest for optimizing the therapeutic effect. We have previously developed a method for simulation and visualization of the EF. The aim of the project is to improve the software for quick and user friendly simulations.  

    Methods

    The ELMA software for brain model creation has been improved by adding quick ROI selection and transformation to an electrical conductivity map based on tissue classification through multiple slices of the preoperative MRI. These data are used as input for Comsol Multiphysics simulations of the EF. Two points along the position of the lead, as seen in the postoperative images, are used for correct placement in the brain model. Multiple DBS lead models are pre-programmed. The active contact and amplitude are user-selected.

    Results

    After a simulation the result is visualized with a user defined isolevel or isosurface superimposed on the patients preoperative MRI. An example is shown in Fig. 1. The 3389 lead is places in zona inserta (Zi) and contact 1 activated with 2 and 4 V respectively. An isolevel of 0.2 V/mm is used corresponding to a ~ 3-4 µm axon diameter when using a pulse length of 60 µs. More examples will be presented at the meeting.

    Conclusion

    The software for patient-specific simulations of EF around DBS electrodes has been improved for quicker simulations and more DBS leads. As a next step user friendly Apps will be implemented.

  • 3029.
    Wårdell, Karin
    et al.
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för medicinsk teknik, Biomedicinsk instrumentteknik.
    Latorre, Malcolm
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för medicinsk teknik, Biomedicinsk instrumentteknik.
    Chan, Adrian D.C.
    Department of Systems and Computer Engineering, Carleton University, Ottawa, Canada.
    The Paxon – A Physical Axonal Mimic2013Konferensbidrag (Refereegranskat)
  • 3030.
    Wårdell, Karin
    et al.
    Linköpings universitet, Institutionen för medicinsk teknik, Biomedicinsk instrumentteknik. Linköpings universitet, Tekniska högskolan.
    Naver, H.K.
    Nilsson, Gert
    Linköpings universitet, Institutionen för medicinsk teknik, Biomedicinsk instrumentteknik. Linköpings universitet, Tekniska högskolan.
    Wallin, B.G.
    The cutaneous vascular axon reflex in humans characterized by laser Doppler perfusion imaging1993Ingår i: Journal of Physiology, ISSN 0022-3751, E-ISSN 1469-7793, Vol. 460, s. 185-199Artikel i tidskrift (Refereegranskat)
  • 3031.
    Wårdell, Karin
    et al.
    Linköpings universitet, Institutionen för medicinsk teknik, Biomedicinsk instrumentteknik. Linköpings universitet, Tekniska högskolan. Linköpings universitet, Centrum för medicinsk bildvetenskap och visualisering, CMIV.
    Rejmstad, Peter
    Linköpings universitet, Institutionen för medicinsk teknik, Biomedicinsk instrumentteknik. Linköpings universitet, Tekniska högskolan.
    Hemm-Ode, Simone
    Linköpings universitet, Institutionen för medicinsk teknik, Biomedicinsk instrumentteknik. Linköpings universitet, Tekniska högskolan. Institute for Medical and Analytical Technologies, University of Applied Sciences and Art Northwestern Switzerland, Basel.
    Richter, Johan
    Linköpings universitet, Institutionen för medicinsk teknik, Biomedicinsk instrumentteknik. Linköpings universitet, Tekniska högskolan. Östergötlands Läns Landsting, Sinnescentrum, Neurokirurgiska kliniken US.
    Zsigmond, Peter
    Linköpings universitet, Institutionen för klinisk och experimentell medicin, Avdelningen för neurovetenskap. Linköpings universitet, Hälsouniversitetet. Östergötlands Läns Landsting, Sinnescentrum, Neurokirurgiska kliniken US.
    Microvascular Blood Flow in the Deep Brain Structures - Laser Doppler Measurements during DBS-implantations2014Ingår i: Movement Disorders 2014, Volym 29, Suppl 1 :1271, 2014Konferensbidrag (Övrigt vetenskapligt)
  • 3032.
    Wårdell, Karin
    et al.
    Linköpings universitet, Institutionen för medicinsk teknik, Biomedicinsk instrumentteknik. Linköpings universitet, Tekniska högskolan.
    Richter, Johan C.O.
    Linköpings universitet, Institutionen för medicinsk teknik, Biomedicinsk instrumentteknik. Linköpings universitet, Tekniska högskolan. Östergötlands Läns Landsting, Sinnescentrum, Neurokirurgiska kliniken US.
    Zsigmond, Peter
    Linköpings universitet, Institutionen för klinisk och experimentell medicin, Neurokirurgi. Linköpings universitet, Hälsouniversitetet. Östergötlands Läns Landsting, Sinnescentrum, Neurokirurgiska kliniken US.
    Hemm, Simone
    Institute for Medical and Analytical Technologies, University of Applied Sciences, Northwestern Switzerland.
    Optical measurements for guidance during deep brain stimulation implantation2011Konferensbidrag (Refereegranskat)
  • 3033.
    Wårdell, Karin
    et al.
    Linköpings universitet, Institutionen för medicinsk teknik, Biomedicinsk instrumentteknik. Linköpings universitet, Tekniska högskolan.
    Richter, Johan
    Linköpings universitet, Institutionen för medicinsk teknik. Linköpings universitet, Hälsouniversitetet. Östergötlands Läns Landsting, Sinnescentrum, Neurokirurgiska kliniken US.
    Zsigmond, Peter
    Linköpings universitet, Institutionen för klinisk och experimentell medicin, Neurokirurgi. Linköpings universitet, Hälsouniversitetet. Östergötlands Läns Landsting, Sinnescentrum, Neurokirurgiska kliniken US.
    Hemm, Simone
    Fachhochschule Nordwestschweiz.
    Intraoperative laser doppler measurements for navigation during deep brain stimulation implantation2012Konferensbidrag (Övrigt vetenskapligt)
  • 3034.
    Wårdell, Karin
    et al.
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för medicinsk teknik, Biomedicinsk instrumentteknik.
    Zsigmond, Peter
    Linköpings universitet, Institutionen för klinisk och experimentell medicin, Neurokirurgi. Linköpings universitet, Hälsouniversitetet. Östergötlands Läns Landsting, Sinnescentrum, Neurokirurgiska kliniken US.
    Rejmstad, Peter
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för medicinsk teknik, Biomedicinsk instrumentteknik.
    Åneman, Oscar
    Linköpings universitet, Institutionen för klinisk och experimentell medicin. Linköpings universitet, Hälsouniversitetet.
    Hillman, Jan
    Linköpings universitet, Institutionen för klinisk och experimentell medicin. Linköpings universitet, Hälsouniversitetet. Östergötlands Läns Landsting, Sinnescentrum, Neurokirurgiska kliniken US.
    Combined laser Doppler and reflectance spectroscopy measurements during brain surgery2013Konferensbidrag (Övrigt vetenskapligt)
  • 3035.
    Wårdell, Karin
    et al.
    Linköpings universitet, Institutionen för medicinsk teknik, Avdelningen för medicinsk teknik. Linköpings universitet, Tekniska fakulteten.
    Zsigmond, Peter
    Linköpings universitet, Institutionen för klinisk och experimentell medicin, Avdelningen för neuro- och inflammationsvetenskap. Linköpings universitet, Medicinska fakulteten. Region Östergötland, Sinnescentrum, Neurokirurgiska kliniken US.
    Richter, Johan
    Linköpings universitet, Institutionen för medicinsk teknik. Linköpings universitet, Tekniska fakulteten. Linköpings universitet, Institutionen för klinisk och experimentell medicin. Linköpings universitet, Medicinska fakulteten. Region Östergötland, Sinnescentrum, Neurokirurgiska kliniken US.
    Hemm, Simone
    Linköpings universitet, Institutionen för medicinsk teknik. Linköpings universitet, Tekniska fakulteten. Institute for Medical and Analytical Technologies, University of Applied Sciences and Arts Northwestern Switzerland, Muttenz, Switzerland.
    Optical Guidance System for Deep Brain Stimulation Surgery: from Experimental Studies to Clinical Use2018Ingår i: , Hollywood, Florida, United States, 2018, artikel-id CTh2B.3Konferensbidrag (Refereegranskat)
    Abstract [en]

    Laser Doppler flowmetry (LDF) has been adapted for optical guidance during stereotactic deep brain stimulation (DBS) surgery. It has been used in more than 130 DBS implantations. The necessary steps to go from experimental studies to clinical use in the neurosurgical setting are reviewed.

  • 3036.
    Wårdell, Karin
    et al.
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för medicinsk teknik, Biomedicinsk instrumentteknik.
    Zsigmond, Peter
    Linköpings universitet, Institutionen för klinisk och experimentell medicin, Neurokirurgi. Linköpings universitet, Hälsouniversitetet. Östergötlands Läns Landsting, Sinnescentrum, Neurokirurgiska kliniken US.
    Richter, Johan
    Linköpings universitet, Institutionen för klinisk och experimentell medicin, Neurokirurgi. Linköpings universitet, Hälsouniversitetet.
    Hemm, Simone
    University of Applied Sciences Northwestern Switzerland, Institute for Medical and Analytical Technologies, Muttenz, Switzerland..
    Relationship Between Laser Doppler Signals and Anatomy During Deep Brain Stimulation Electrode Implantation Toward the Ventral Intermediate Nucleus and Subthalamic Nucleus2013Ingår i: Neurosurgery, ISSN 0148-396X, E-ISSN 1524-4040, Vol. 72, nr 2, s. 127-140Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    BACKGROUND: Deep brain stimulation (DBS) requires precise and safe navigation to the chosen target. Optical measurements allow monitoring of gray-white tissue boundaries (total light intensity [TLI]) and microvascular blood flow during stereotactic procedures.

    OBJECTIVE: To establish the link between TLI/blood flow and anatomy along trajectories toward the ventral intermediate nucleus (Vim) and subthalamic nucleus (STN).

    METHODS: Stereotactic laser Doppler measurements were obtained with millimeter precision from the cortex toward the Vim (n = 13) and STN (n = 9). Optical trajectories of TLI and blood flow were created and compared with anatomy by superimposing the Schaltenbrandt-Wahren atlas on the patients' pre- and postoperative images. Measurements were divided into anatomic subgroups and compared statistically.

    RESULTS: Typical TLI trajectories with well-defined anatomic regions could be identified for the Vim and STN. TLI was significantly lower (P < .001) and microvascular blood flow significantly higher (P = .01) in the Vim targets. Of 1285 sites, 38 showed blood flow peaks, 27 of them along the Vim trajectories. High blood flow was more common close to the sulci and in the vicinity of the caudate/putamen. Along 1 Vim trajectory, a slight bleeding was suspected during insertion of the probe and confirmed with postoperative computed tomography.

    CONCLUSION: Laser Doppler is useful for intraoperative guidance during DBS implantation because simultaneous measurement of tissue grayness and microvascular blood flow can be done along the trajectory with millimeter precision. Typical but different TLI trajectories were found for the Vim and STN.

  • 3037.
    Wårdell, Karin
    et al.
    Linköpings universitet, Institutionen för medicinsk teknik, Biomedicinsk instrumentteknik. Linköpings universitet, Tekniska högskolan.
    Åström, Mattias
    Linköpings universitet, Institutionen för medicinsk teknik, Biomedicinsk instrumentteknik. Linköpings universitet, Tekniska högskolan. Sapiens Steering Brain Stimulation B.V., The Netherlands .
    Diczfalusy, Elin
    Linköpings universitet, Institutionen för medicinsk teknik, Biomedicinsk instrumentteknik. Linköpings universitet, Tekniska högskolan.
    Martens, Hubert
    Sapiens Steering Brain Stimulation B.V., The Netherlands.
    Surgical Therapy: Parkinson's disease2014Ingår i: Movement DisordersSupplement: Abstracts of the Eighteenth International Congress of Parkinson's Disease and Movement Disorders, John Wiley & Sons, 2014, Vol. 29, s. 1170-1170, artikel-id Suppl 1:1170Konferensbidrag (Övrigt vetenskapligt)
    Abstract [en]

    Objective: To analyze the relationship between the electric field and the volume of tissue activated (VTA) during model-based investigations of deep brain stimulation (DBS).

    Background: An important factor for the therapeutic outcome of DBS is the spatial distribution of the stimulation field in the target area. Finite element models and simulations of DBS are increasingly being used to study the distribution of the stimulation field in relation to patient specific anatomy. The stimulation field is often defined as a VTA derived from computational axon models that are coupled to the finite element simulations. This approach however, is not feasible in many research centers due to the complexity of developing a computational axon model, as well as the extensive execution time when solving such models.

    Methods: A detailed computer axon cable model was developed to study axonal activation in response to various DBS stimulation configurations. A range of axon models were set up and coupled to finite element models of DBS. DBS simulations were performed for Medtronic lead model 3389 during monopolar configurations for a range of amplitudes and pulse widths. Activation thresholds for the electric fields were derived by measuring the field strength at the maximum radius of activation for each configuration.

    Results: Simulations showed that the electric field thresholds were related to stimulation amplitude, pulse width, and axon diameter. For large axons, the electric field threshold was not dependent on the amplitude, thus implying a low sensitivity of the electric field curvature.

    Conclusions: Electric field thresholds can be used to predict the VTA during model-based investigations of DBS without the necessity of computer axon models. The use of electric field thresholds may substantially simplify the process of performing model-based investigations of DBS in the future.

  • 3038.
    Xia, Qingling
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Medicinteknik och hälsosystem, Neuronik. Chongqing University.
    Infrared Neural Modulation: Photothermal Effects on Cortex Neurons Using Infrared Laser Heating2018Licentiatavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    It would be of great value to have a precise and non-damaging neuromodulation technique in the field of basic neuroscience research and for clinical treatment of neurological diseases. Infrared neural modulation (INM) is a new modulation modality developed in the last decade, which uses pulsed or continues infrared (IR) light with a wavelength of 1200 to 2200 nm to directly alter neural signals. INM includes both infrared neural stimulation (INS) and infrared neural inhibition (INI). INM is widely investigated for use on peripheral nerves, cochlear nerve fibers, cardiac cells, and the central nervous system. This technique holds the advantages of contact-free and high spatiotemporal precision compared to the traditional electrical stimulation. It does not depend on genetic modification and exogenous absorbers as other optical techniques, such as the optogenetic technique and the enhanced near-infrared neural stimulation (e-NIR). These advantages make INM a viable technique for research and clinical applications. The primary mechanism of the INM is believed to be a photothermal effect, where the IR laser energy absorbed by water leads to a rapid local temperature change. However, so far the details of the mechanism of action potential (AP) generation and inhibition remain elusive. Another issueis that the cells may be endangeredbythe heat exposure, consequently triggering a physiologicalmalfunction or even permanent damage.These concernshave hindered the transfer of the INM technique to the clinical therapy.Therefore, the general aim of this study was to improve the understanding of the details of how INM affects the cells. Laser parameters for safe and efficient stimulation were investigated on the basis of being useful for clinical applications. A tailored heating model and in vitro INM experiments on cortex neurons were used to reach this goal.The first paper was a feasibility study. A 1550nm laser with a beam spot diameter of around 6 mm was used to irradiate the rat cortex neurons, which were seeded on multi-electrode arrays (MEA) and formed well-connected networks. A heating model based on an estimated laser beam (standard Gaussian distribution) was used to simulate temperaturechanges. The damage signal ratio (DSR),based on the temperature,was calculated to predict the heat damage. The average spike rate of all the working electrodes from two MEAs was used to evaluate the degree of theinhibition of the neural networks. Results IVshowed that it is possible to use the 1550 nm laser to safely inhibit the neural network activity and that the degree of the INI is dependent on the power of the laser.The second paper wasan application and mechanism study. The aim of this study was to investigate the safety, efficiency, and cellular mechanism of INI. The same laser as in paper Iwas used in this study. A 20 X objective was used to decrease the beam spot diameteraround 240 μm. The measured laser profile (high order Gaussian beam) was used in the heating model to predict the temperature. The model was verified by local temperature measurements viamicropipette. The action potential rates, measured by the MEA electrodes, were quantified for different temperatures. Bicuculline was added to the cortex neuron cultures to induce hyperexcitation of the neural network. The results showed that the INI is temperature dependent and that the temperature needs to be less than 46 °C at 30 s laser irradiation for safe inhibition. The IR laser couldalso be used to inhibit the hyperexcitedactivity. The degree of inhibition, for the assessed subpopulation of neurons, was better correlated with the action potential amplitude than the width of it and INIcan be accomplished without inhibitory synapses

  • 3039.
    Xia, Qingling
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Medicinteknik och hälsosystem, Neuronik. Chongqing University.
    Nyberg, Tobias
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Medicinteknik och hälsosystem, Neuronik.
    Inhibition of Cortical Neural Networks Using Infrared LaserManuskript (preprint) (Övrigt vetenskapligt)
  • 3040.
    Xia, Qingling
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Medicinteknik och hälsosystem, Neuronik. Chongqing University.
    Nyberg, Tobias
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Medicinteknik och hälsosystem, Neuronik.
    Photothermal Inhibition of Cortex Neurons Activity by Infrared Laser2018Ingår i: World Congress on Medical Physics and Biomedical Engineering 2018, 2018, Vol. 68/3, s. 99-104Konferensbidrag (Refereegranskat)
    Abstract [en]

    Some brain diseases are caused by neurons being abnormally excited, such as Parkinson’s disease (PD) and epilepsy. The aim of this study was to investigate the feasibility and the efficacy of infrared laser irradiation for inhibiting neuronal network activity. We cultured rat cortex neurons, forming neural networks with spontaneous neural activity, on multi-electrode arrays (MEAs). To inhibit the activity of the networks we irradiated the neurons using different intensity of 1550 nm infrared laser light. A temperature model was created using COMSOL Multiphysics software to predict the temperature change at different laser intensity irradiation. Our initial result shows that the wavelength of 1550 nm infrared laser can be used to inhibit the network activity of cultivated rat cortex neurons directly and reversibly. The degrees of network inhibition can be manipulated by changing the laser intensity. The optical thermal effect is considered the primary mechanism during infrared neural inhibition (INI). These results demonstrate that INI could potentially be useful in the treatment of neurological disorders and that temperature may play an important role in INI.

  • 3041.
    Xia, Wei
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Chang, Jiang
    Shanghai Institute of ceramics, Chinese academy of sciences.
    Design of bioactive materials for bone repair and regeneration2017Bok (Refereegranskat)
  • 3042.
    Xia, Wei
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Chang, Jiang
    Shanghai Institute of ceramics, Chinese academy of sciences.
    Engqvist, Håkan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Biological effect of ions in calcium phosphates on bone regeneration2017Ingår i: Design of bioactive materials for bone repair and regeneration, World Scientific, 2017Kapitel i bok, del av antologi (Refereegranskat)
  • 3043.
    Xia, Wei
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Engqvist, Håkan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Calcium phosphate hollow spheres: carriers and repair2016Konferensbidrag (Refereegranskat)
  • 3044.
    Xia, Wei
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Fu, Le
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Engqvist, Håkan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Critical cracking thickness of calcium phosphates biomimetic coating: Verification via a Singh-Tirumkudulu model2017Ingår i: Ceramics International, ISSN 0272-8842, E-ISSN 1873-3956, Vol. 43, s. 15729-15734Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Despite the many advantages of biomimetic calcium phosphates (CaPs) coatings, there is a troublesome problem of low cohesion in the coatings. The low cohesion originates from the absence of bonding between CaP crystals, leading to cracks during drying of the coatings. In this study, based on a simplified Singh-Tirumkudulu model, the critical cracking thickness (CCT) of biomimetic CaPs coatings has been calculated. CaPs crystal size is the key factor influencing the CCT, except for the particle's shear modulus. Biomimetic CaPs coatings with different thickness have been prepared by soaking Ti substrates with a transition layer of TiO2 (rutile) in Dulbecco's phosphate buffer saline solution (DPBS) for 1, 2, 4 and 6 weeks. The morphology, thickness, and whether cracks formed or not were evaluated by SEM. The simplified Singh and Tirumkudulu model has been verified in terms of our experimental results and data obtained from previous literatures. Via dedicated experiments and calculations it is concluded that a thickness of about approximately 2 gm is the critical value for a crack-free CaPs coating given that the CaPs crystal size is smaller than 100 nm. The model could be used in the future design of crack-free biomimetic coatings.

  • 3045.
    Xia, Wei
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Qin, Tao
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Suska, Felicia
    Engqvist, Håkan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Bioactive spheres: the way of treating dentin hypersensitivity2016Ingår i: ACS biomaterials science and engineering, ISSN 2373-9878, Vol. 2, nr 5, s. 734-740Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Sealing exposed dental tubules is the most effective and long-term way to relieve the pain induced by dental sensitivity. A bioactive hollow sphere (strontium substituted calcium phosphate) was synthesized and added in toothpaste to study its effect on dental hypersensitivity via tooth tubules occlusion and mineralization. The size of spheres is perfect for penetrating into dental tubules, reaching to 20 pm into the tubules. The exposed dental tubules were occluded by spheres and new apatite layer after 3 days brushing. The spheres attached to the surface of dentin and the mineralized surface contained two layers, a porous layer followed by a dense apatite layer. The porous layer can be dissolved in an acidic solution, but the following dense layer could be kept even after soaking in an acid solution. In conclusion, Sr-substituted calcium phosphate spheres could be a good candidate for at-home treatment of dental hypersensitivity.

  • 3046.
    Xie, Haiyan
    et al.
    Dept. of Physics, Lund University, Sweden.
    Haj-Hosseini, Neda
    Linköpings universitet, Institutionen för medicinsk teknik, Biomedicinsk instrumentteknik. Linköpings universitet, Tekniska högskolan.
    Richter, Johan
    Linköpings universitet, Institutionen för medicinsk teknik. Linköpings universitet, Tekniska högskolan. Östergötlands Läns Landsting, Sinnescentrum, Neurokirurgiska kliniken US.
    Wårdell, Karin
    Linköpings universitet, Institutionen för medicinsk teknik, Biomedicinsk instrumentteknik. Linköpings universitet, Tekniska högskolan.
    Andersson-Engels, Stefan
    Dept. of Physics, Lund University, Sweden.
    Fluorescence spectroscopy for guiding malignant brain tumour resection with Optical Touch Pointer2010Konferensbidrag (Refereegranskat)
    Abstract [en]

    Glioblastoma multiforme (GBM), a highly malignant primary brain tumor, is difficult to distinguish from from its surrounding functioning tissue under direct vision in the operating field, since it grows in an infiltrative growth pattern. The main challenge in the surgical treatment of GBM is to fully resect the tumor and avoid neurological impairment. In this paper we extend previous proof-of-principle studies by extending the clinical potential of OTP with the introduction of more sophisticated multivariate analysis schemes. The aim is to distinguish tumor and healthy tissue as well as possible using singular value decomposition (SVD) and cluster analysis methods.

  • 3047. Xie, L.
    et al.
    Zheng, Li-rong
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Industriell och Medicinsk Elektronik.
    Yang, G.
    Hybrid integration technology for wearable sensor systems2016Ingår i: Internet of Things and Advanced Application in Healthcare, IGI Global , 2016, s. 98-137Kapitel i bok, del av antologi (Övrigt vetenskapligt)
    Abstract [en]

    Personalized and pervasive healthcare devices help seamlessly integrate healthcareand wellness into the daily life, independent of time and space. Silicon IntegratedCircuit (IC) has been used in many advanced healthcare applications due to thecompact size and ultra-low power consumption. Meanwhile, printed electronics(PE) is considered as a promising approach enabling cost-effective manufacturingof thin, flexible, and light-weight devices. A hybrid integration of IC and PE providesa new solution for the future wearable healthcare devices. In this chapter, firstlya customized bio-sensing IC is demonstrated, which can detect and process variousbio-signals; secondly, the feasibility and performance of using inkjet printingtechnology as enabling technology has been examined for the fabrication of flexiblebio-sensing devices. Finally, a wearable and flexible Bio-Patch is presented byleveraging hybrid integration of PE and bio-sensing IC. In-vivo test results showthat the flexible Bio-Patch provides high quality ECG signal comparable with theone gained by bedside ECG machine.

  • 3048.
    Xie, Li
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Elektroniksystem. KTH, Skolan för informations- och kommunikationsteknik (ICT), Centra, VinnExcellence Center for Intelligence in Paper and Packaging, iPACK.
    Yang, Geng
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Elektroniksystem. KTH, Skolan för informations- och kommunikationsteknik (ICT), Centra, VinnExcellence Center for Intelligence in Paper and Packaging, iPACK.
    Xu, Linlin
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Centra, VinnExcellence Center for Intelligence in Paper and Packaging, iPACK.
    Seoane, Fernando
    KTH, Skolan för teknik och hälsa (STH), Medicinsk teknik, Medicinska sensorer, signaler och system.
    Chen, Qiang
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Elektroniksystem. KTH, Skolan för informations- och kommunikationsteknik (ICT), Centra, VinnExcellence Center for Intelligence in Paper and Packaging, iPACK.
    Zheng, Lirong
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Elektroniksystem. KTH, Skolan för informations- och kommunikationsteknik (ICT), Centra, VinnExcellence Center for Intelligence in Paper and Packaging, iPACK. State Key Laboratory of ASICs and Systems, Fudan University, 200433, Shanghai, China .
    Characterization of dry biopotential electrodes2013Ingår i: Proceedings of the Annual International Conference of the IEEE Engineering in Medicine and Biology Society, EMBS, 2013, s. 1478-1481Konferensbidrag (Refereegranskat)
    Abstract [en]

    Driven by the increased interest in wearable long-term healthcare monitoring systems, varieties of dry electrodes are proposed based on different materials with different patterns and structures. Most of the studies reported in the literature focus on proposing new electrodes and comparing its performance with commercial electrodes. Few papers are about detailed comparison among different dry electrodes. In this paper, printed metal-plate electrodes, textile based electrodes, and spiked electrodes are for the first time evaluated and compared under the same experimental setup. The contact impedance and noise characterization are measured. The in-vivo electrocardiogram (ECG) measurement is applied to evaluate the overall performance of different electrodes. Textile electrodes and printed electrodes gain comparable high-quality ECG signals. The ECG signal obtained by spiked electrodes is noisier. However, a clear ECG envelope can be observed and the signal quality can be easily improved by backend signal processing. The features of each type of electrodes are analyzed and the suitable application scenario is addressed.

  • 3049.
    Xie, Yuting
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska fakulteten. Sichuan University.
    An Automatic Localization Algorithm for Ultrasound Breast Tumors Based on Human Visual Mechanism2017Ingår i: Sensor of Journals, ISSN 1424-8220, Vol. 17, nr 5Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Human visual mechanisms (HVMs) can quickly localize the most salient object in natural images, but it is ineffective at localizing tumors in ultrasound breast images. In this paper, we research the characteristics of tumors, develop a classic HVM and propose a novel auto-localization method. Comparing to surrounding areas, tumors have higher global and local contrast. In this method, intensity, blackness ratio and superpixel contrast features are combined to compute a saliency map, in which a Winner Take All algorithm is used to localize the most salient region, which is represented by a circle. The results show that the proposed method can successfully avoid the interference caused by background areas of low echo and high intensity. The method has been tested on 400 ultrasound breast images, among which 376 images succeed in localization. This means this method has a high accuracy of 94.00%, indicating its good performance in real-life applications. 

  • 3050. Xing, Zhe
    et al.
    Xue, Ying
    Dånmark, Staffan
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik.
    Finne-Wistrand, Anna
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik.
    Arvidson, Kristina
    Hellem, Solve
    Yang, Zhuang-Qun
    Mustafa, Kamal
    Comparison of short-run cell seeding methods for poly(L-lactide-co-1,5-dioxepan-2-one) scaffold intended for bone tissue engineering2011Ingår i: International Journal of Artificial Organs, ISSN 0391-3988, E-ISSN 1724-6040, Vol. 34, nr 5, s. 432-441Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Constructs intended for bone tissue engineering are influenced by the initial cell seeding procedure. The seeding method should be rapid, convenient, improve cell spatial distribution, and have no negative effects on cellular viability and differentiation. This study aimed to compare the effect of short-run seeding methods (centrifuge and vortex) with a static method on the scaffolds prepared from poly(L-lactide-co-1,5-dioxepan-2-one) by solvent-casting particulate-leaching (SCPL) technique. Human osteoblast-like cells (HOB) were seeded by the three methods described above. The seeding efficiency was determined by attached cell numbers. Cellular proliferation was analyzed by WST-1 and dsDNA assay. Cell distribution was examined by scanning electron (SEM) and fluorescence microscopy. Expression of Alkaline Phosphatase (ALP), Collagen type I (Col I), Osteocalcin (OC) and Proliferating Cell Nuclear Antigen (PCNA) were determined by real time RT-PCR. Results indicated that centrifuge and vortex increased seeding efficiency and had no negative effects on cellular viability. The data obtained by the fluorescence microscope confirmed the SEM results that the vortex method improved cell distribution through the scaffolds more than the other two methods (p<0.05). The RT-PCR results showed no significant differences on the expression of mRNA between the three methods of the above markers. The vortex method was found to be a simple and feasible seeding method for the poly(L-lactide-co-1,5-dioxepan-2-one) scaffolds.

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