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  • 201.
    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.

  • 202.
    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)
  • 203.
    Babic, Ankica
    et al.
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för medicinsk teknik, Medicinsk informatik.
    Ster, Branko
    Computer and Inforamtion Science University of Ljubljana.
    Pavesic, Nikola
    Electrical Engineering University of Ljubljana.
    Wigertz, Ove
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för medicinsk teknik, Medicinsk informatik.
    Machine Learning for the quality of life in inflammatory bowel disease1997Inngår i: Medical Informatics Europe97,1997, Amsterdam: IOS Press , 1997, s. 661-Konferansepaper (Fagfellevurdert)
  • 204.
    Babic, Ankica
    et al.
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för medicinsk teknik, Medicinsk informatik.
    Zganec, Mario
    University of Ljubljana .
    Palcic, Branko
    Cancer Research Centre BC Canada.
    3D presentation of the nuclear cell features in quantitative cytometry1996Inngår i: AMIA 1996,1996, Washington: Hanley & Belfus , 1996, s. 679-Konferansepaper (Fagfellevurdert)
  • 205.
    Babic, Ankica
    et al.
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för medicinsk teknik, Medicinsk informatik.
    Åhlfeldt, Hans
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för medicinsk teknik, Medicinsk informatik.
    Wigertz, Ove
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för medicinsk teknik, Medicinsk informatik.
    Bodemar, Göran
    Linköpings universitet, Hälsouniversitetet. Linköpings universitet, Institutionen för molekylär och klinisk medicin, Gastroenterologi och hepatologi. Östergötlands Läns Landsting, Medicincentrum, Endokrin- och magtarmmedicinska kliniken US.
    Mathiesen, Ulrik
    Oskarshamn Hospital .
    Artificial neural networks in clustering and classification of data on unspecified liver diseases1993Inngår i: Nordic Meeting on Medical and Biomeidical engineering,1993, 1993, s. 136-Konferansepaper (Fagfellevurdert)
  • 206. Bader, Dan
    et al.
    Clark, Michael
    Dealey, Carol
    Rithalia, Shyam
    Oomens, Cees
    Goossens, Richard
    Ask, Per
    Linköpings universitet, Institutionen för medicinsk teknik. Linköpings universitet, Tekniska högskolan.
    Lindgren, Margareta
    Linköpings universitet, Institutionen för medicin och hälsa, Omvårdnad. Linköpings universitet, Hälsouniversitetet.
    Takahashi, Makamoto
    Laboratory measurement of the interface pressures applied by active therapy support surfaces: A consensus document2010Inngår i: Journal of Tissue Viability, ISSN 0965-206X, Vol. 19, nr 1, s. 2-6Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A key element in pressure ulcer prevention and management is the selection of appropriate pressure redistributing (PR) patient support surfaces for use while seated and in bed. However little explicit guidance exists allowing standardised quantitative comparison of different PR surfaces based upon their ability to redistribute pressure from anatomical landmarks such as the heels and sacrum. In 2008 a working group was established in Europe through the US National Pressure Ulcer Advisory Panel (NPUAP) support surface standardisation initiative (S3I) and under the aegis of the European Pressure Ulcer Advisory Panel with the specific remit of developing test methods for the evaluation of active therapy support surfaces (alternating pressure air mattresses). This report describes a consensus development process to agree test methods appropriate to compare active therapy surfaces based upon their ability to redistribute pressure from the sacrum and the heels.

  • 207.
    Baeza Ortega, José Antonio
    Linköpings universitet, Centrum för medicinsk bildvetenskap och visualisering, CMIV. Linköpings universitet, Institutionen för medicinsk teknik. Linköpings universitet, Tekniska högskolan.
    Combined Visualization of Intracardiac Blood Flow and Wall Motion Assessed by MRI2011Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    MRI is a well known and widely spread technique to characterize cardiac pathologies due to its high spatial resolution, its accessibility and its adjustable contrast among soft tissues.

    In attempt to close the gap between blood flow, myocardial movement and the cardiac fucntion, researching in the MRI field addresses the quantification of some of the most relevant blood and myocardial parameters.

    During this proyect a new tool that allows reading, postprocessing, quantifying and visualizing 2D motion sense MR data has been developed. In order to analyze intracardiac blood flow and wall motion, the new tool quantifies velocity, turbulent kinetic energy, pressure and strain.

    In the results section the final tool is presented, describing the visualization modes, which represent the quantified parameters both individually and combined; and detailing auxiliary tool features as masking, thresholding, zooming, and cursors.

    Finally, thecnical aspects as the convenience of two dimensional examinations to create compact tools, and the challenges of masking as part of the relative pressure calculation, among others, are discussed; ending up with the proposal of some future developments.

  • 208.
    Bak, Zoltan
    et al.
    Linköpings universitet, Institutionen för medicinsk teknik. Linköpings universitet, Tekniska högskolan.
    Sjöberg, Folke
    Linköpings universitet, Institutionen för klinisk och experimentell medicin, Brännskadevård. Linköpings universitet, Hälsouniversitetet.
    Eriksson, Olle
    Linköpings universitet, Institutionen för datavetenskap, Statistik. Linköpings universitet, Filosofiska fakulteten.
    Steinvall, Ingrid
    Linköpings universitet, Institutionen för klinisk och experimentell medicin. Linköpings universitet, Hälsouniversitetet.
    Janerot Sjöberg, Birgitta
    Linköpings universitet, Institutionen för medicin och hälsa, Klinisk fysiologi. Linköpings universitet, Hälsouniversitetet.
    Cardiac dysfunction after burns2008Inngår i: Burns, ISSN 0305-4179, E-ISSN 1879-1409, Vol. 34, nr 5, s. 603-609Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Objectives

    Using transoesophageal echocardiography (TEE) we investigated the occurrence, and the association of possible abnormalities of motion of the regional wall of the heart (WMA) or diastolic dysfunction with raised troponin concentrations, or both during fluid resuscitation in patients with severe burns.

    Patients and methods

    Ten consecutive adults (aged 36–89 years, two women) with burns exceeding 20% total burned body surface area who needed mechanical ventilation were studied. Their mean Baux index was 92.7, and they were resuscitated according to the Parkland formula. Thirty series of TEE examinations and simultaneous laboratory tests for myocyte damage were done 12, 24, and 36 h after the burn.

    Results

    Half (n = 5) the patients had varying grades of leakage of the marker that correlated with changeable WMA at 12, 24 and 36 h after the burn (p ≤ 0.001, 0.044 and 0.02, respectively). No patient had WMA and normal concentrations of biomarkers or vice versa. The mitral deceleration time was short, but left ventricular filling velocity increased together with stroke volume.

    Conclusion

    Acute myocardial damage recorded by both echocardiography and leakage of troponin was common, and there was a close correlation between them. This is true also when global systolic function is not deteriorated. The mitral flow Doppler pattern suggested restrictive left ventricular diastolic function.

  • 209.
    Balkanyi, Laszlo
    et al.
    European Centre for Disease Prevention and Control, Stockholm, Sweden.
    Schulz, Stefan
    Medizinische Universität Graz, Austria and Freiburg University Medical Center, Freiburg, Germany.
    Cornet, Ronald
    Linköpings universitet, Institutionen för medicinsk teknik, Medicinsk informatik. Linköpings universitet, Tekniska högskolan.
    Bodenreider, Olivier
    National Library of Medicine, Bethsheda, USA.
    Medical concept representation: the years beyond 2000.2013Inngår i: Proceedings of Studies in Health Technology & Informatics, vol. 192, IOS Press, 2013, Vol. 192, s. 1011-1011Konferansepaper (Fagfellevurdert)
    Abstract [en]

    This work aims at understanding the state of the art in the broad contextual research area of "medical concept representation". Our data support the general understanding that the focus of research has moved toward medical ontologies, which we interpret as a paradigm shift. Both the opinion of socially active groups of researchers and changes in bibliometric data since 1988 support this opinion. Socially active researchers mention the OBO foundry, SNOMED CT, and the UMLS as anchor activities.

  • 210.
    Balsiger, Fabian
    Linköpings universitet, Institutionen för medicinsk teknik, Biomedicinsk instrumentteknik. Linköpings universitet, Tekniska högskolan.
    Brain Tumor Volume Calculation: Segmentation and Visualization Using MR Images2012Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [en]

    Background: Glioblastomas are highly aggressive and malignant brain tumors which are difficult to resect totally. The surgical extent of resection constitutes a key role due to its direct influence on the patient’s survival time. To determine the resection extent, the tumor volume on pre-operative and post-operative magnetic resonance (MR) images should be calculated and compared.

    Materials and Methods: An active contour segmentation method was implemented to segment glioblastoma brain tumors on pre-operative T1-contrast enhanced MR images in axial, coronal and sagittal planes by self-developed software. The volume was rendered from the tumor  contours using Delaunay triangulation. Besides the segmentation and volume rendering, a graphical user interface was developed to facilitate the rendering, visualization and volume calculation of the brain tumor. The software was implemented in MATLAB (version 7.2). Two MR image data sets from glioblastoma patients were used and the repeatability and reproducibility of volume calculation was tested. Dimensions of the calculated tumor volume were then compared to the dimensions obtained in Amira® software.

    Results: The tumor volumes for data set 1 and data set 2 were 62.7 and 39.0 cm3, respectively. When tumor was segmented by different users (n=4), the volumes were 62.5 ± 0.3 and 42.6 ± 3.5 cm3. Segmentation errors were seen during the segmentation of data set 2. Mainly under- and over-segmentation due to hypointense MR signals caused by cerebrospinal fluid, or hyperintense MR signals caused by skull bone and weak tumor boundaries led to wrong segmentation results.

    Conclusion: Segmentation using active contours method is able to detect the brain tumor boundaries. The volume rendering and visualization allows the user to explore the tumor tissue and its surrounding interactively. Using the software, tumor volume is precisely calculated.

  • 211.
    Baranowski, Jacek
    et al.
    Östergötlands Läns Landsting, Hjärt- och Medicincentrum, Fysiologiska kliniken US.
    Ahn, Henrik
    Linköpings universitet, Institutionen för medicin och hälsa, Thoraxkirurgi. Linköpings universitet, Hälsouniversitetet. Östergötlands Läns Landsting, Hjärt- och Medicincentrum, Thorax-kärlkliniken i Östergötland.
    Freter, Wolfgang
    Östergötlands Läns Landsting, Hjärt- och Medicincentrum, Thorax-kärlkliniken i Östergötland.
    Nielsen, Niels-Erik
    Linköpings universitet, Institutionen för medicin och hälsa, Kardiologi. Linköpings universitet, Hälsouniversitetet. Östergötlands Läns Landsting, Hjärt- och Medicincentrum, Kardiologiska kliniken US.
    Nylander, Eva
    Linköpings universitet, Institutionen för medicin och hälsa, Klinisk fysiologi. Linköpings universitet, Hälsouniversitetet. Östergötlands Läns Landsting, Hjärt- och Medicincentrum, Fysiologiska kliniken US.
    Janerot-Sjöberg, Birgitta
    Linköpings universitet, Institutionen för medicinsk teknik, Biomedicinsk instrumentteknik. Linköpings universitet, Tekniska högskolan. Östergötlands Läns Landsting, Hjärt- och Medicincentrum, Fysiologiska kliniken US.
    Sandborg, Michael
    Linköpings universitet, Institutionen för medicin och hälsa, Medicinsk radiofysik. Linköpings universitet, Hälsouniversitetet. Östergötlands Läns Landsting, Centrum för kirurgi, ortopedi och cancervård, Radiofysikavdelningen US.
    Wallby, Lars
    Linköpings universitet, Institutionen för medicin och hälsa, Kardiologi. Linköpings universitet, Hälsouniversitetet. Östergötlands Läns Landsting, Hjärt- och Medicincentrum, Fysiologiska kliniken US.
    Echo-guided presentation of the aortic valve minimises contrast exposure in transcatheter valve recipients2011Inngår i: Catheterization and cardiovascular interventions, ISSN 1522-1946, E-ISSN 1522-726X, Vol. 77, nr 2, s. 272-275Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    OBJECTIVES:

    We have developed a method using transthoracic echocardiography in establishing optimal visualization of the aortic root, to reduce the amount of contrast medium used in each patient.

    BACKGROUND:

    During transcatheter aortic valve implantation, it is necessary to obtain an optimal fluoroscopic projection for deployment of the valve showing the aortic ostium with the three cusps aligned in the beam direction. This may require repeat aortic root angiograms at this stage of the procedure with a high amount of contrast medium with a risk of detrimental influence on renal function.

    METHODS:

    We studied the conventional way and an echo guided way to optimize visualisation of the aortic root. Echocardiography was used initially allowing easier alignment of the image intensifier with the transducer's direction.

    RESULTS:

    Contrast volumes, radiation/fluoroscopy exposure times, and postoperative creatinine levels were significantly less in patients having the echo-guided orientation of the optimal fluoroscopic angles compared with patients treated with the conventional approach.

    CONCLUSION:

    We present a user-friendly echo-guided method to facilitate fluoroscopy adjustment during transcatheter aortic valve implantation. In our series, the amounts of contrast medium and radiation have been significantly reduced, with a concomitant reduction in detrimental effects on renal function in the early postoperative phase.

  • 212. Barclay, Susan A
    et al.
    Eidenvall, Lars
    Karlsson, Matts
    Andersson, Gunnar
    Xiong, Changsheng
    Ask, Per
    Linköpings universitet, Institutionen för medicinsk teknik, Fysiologisk mätteknik. Linköpings universitet, Tekniska högskolan.
    Loyd, Dan
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Mekanisk värmeteori och strömningslära. Linköpings universitet, Tekniska högskolan.
    Wranne, Bengt
    Linköpings universitet, Institutionen för medicin och vård, Klinisk fysiologi. Linköpings universitet, Hälsouniversitetet. Östergötlands Läns Landsting, Hjärt- och Medicincentrum, Fysiologiska kliniken US.
    The shape of the proximal isovelocity surface area varies with regurgitant orifice size and distance from orifice: computer simulation and model experiments with color M-mode technique.1993Inngår i: Journal of the American Society of Echocardiography, ISSN 0894-7317, E-ISSN 1097-6795, Vol. 6, nr 4, s. 433-445Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The hemispheric proximal isovelocity surface area method for quantification of mitral regurgitant flow (i.e., Qc = 2 pi r2v), where 2 pi r2 is the surface area and v is the velocity at radius r, was investigated as distance from the orifice was increased. Computer simulations and steady flow model experiments were performed for orifices of 4, 6, and 8 mm. Flow rates derived from the centerline velocity and hemispheric assumption were compared with true flow rates. Proximal isovelocity surface area shape varied as distance from each orifice was increased and could only be approximated from the hemispheric equation when a certain distance was exceeded: > 7, > 10, and > 12 mm for the 4, 6, and 8 mm orifices, respectively. Prediction of relative error showed that the best radial zone at which to make measurements was 5 to 9, 6 to 14 and 7 to 17 mm for the 4, 6, and 8 mm orifices, respectively. Although effects of a nonhemispheric shape could be compensated for by use of a correction factor, a radius of 8 to 9 mm can be recommended without the use of a correction factor over all orifices studied if a deviation in calculated as compared with true flow of 15% is considered acceptable. These measurements therefore have implications for the technique in clinical practice.

  • 213.
    Bardolet Pettersson, Susana
    Linköpings universitet, Institutionen för medicinsk teknik, Avdelningen för medicinsk teknik.
    Managing imbalanced training data by sequential segmentation in machine learning2019Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Imbalanced training data is a common problem in machine learning applications. Thisproblem refers to datasets in which the foreground pixels are significantly fewer thanthe background pixels. By training a machine learning model with imbalanced data, theresult is typically a model that classifies all pixels as the background class. A result thatindicates no presence of a specific condition when it is actually present is particularlyundesired in medical imaging applications. This project proposes a sequential system oftwo fully convolutional neural networks to tackle the problem. Semantic segmentation oflung nodules in thoracic computed tomography images has been performed to evaluate theperformance of the system. The imbalanced data problem is present in the training datasetused in this project, where the average percentage of pixels belonging to the foregroundclass is 0.0038 %. The sequential system achieved a sensitivity of 83.1 % representing anincrease of 34 % compared to the single system. The system only missed 16.83% of thenodules but had a Dice score of 21.6 % due to the detection of multiple false positives. Thismethod shows considerable potential to be a solution to the imbalanced data problem withcontinued development.

  • 214.
    Barlow, Lotti
    et al.
    Fackspråk och informatik, Regler och tillstånd, Socialstyrelsen.
    Gerdin, Ulla
    Fackspråk och informatik, Regler och tillstånd, Socialstyrelsen.
    Almborg, Ann-Helene
    Fackspråk och informatik, Regler och tillstånd, Socialstyrelsen.
    Kron, Bengt
    Regionkansliet Hälso- och sjukvårdsavdelningen, Västra Götalandsregionen.
    Lindberg, Christina
    Fackspråk och informatik, Regler och tillstånd, Socialstyrelsen.
    Bränd Persson, Kristina
    Fackspråk och informatik, Regler och tillstånd, Socialstyrelsen.
    Ahlzén, Karin
    Fackspråk och informatik, Regler och tillstånd, Socialstyrelsen.
    Ericsson, Erika
    Fackspråk och informatik, Regler och tillstånd, Socialstyrelsen.
    Adelöf, Anna
    Fackspråk och informatik, Regler och tillstånd, Socialstyrelsen.
    Karlsson, Daniel
    Linköpings universitet, Institutionen för medicinsk teknik, Medicinsk informatik. Linköpings universitet, Tekniska högskolan.
    Wolff Foster, Lisa
    Fackspråk och informatik, Regler och tillstånd, Socialstyrelsen.
    Widigson, Lena
    Fackspråk och informatik, Regler och tillstånd, Socialstyrelsen.
    Bratt, Maria
    Fackspråk och informatik, Regler och tillstånd, Socialstyrelsen.
    Testi, Stefano
    Fackspråk och informatik, Regler och tillstånd, Socialstyrelsen.
    Staerner Steen, Anna
    Fackspråk och informatik, Regler och tillstånd, Socialstyrelsen.
    Nyström, Mikael
    Linköpings universitet, Institutionen för medicinsk teknik, Medicinsk informatik. Linköpings universitet, Tekniska högskolan.
    Nationellt fackspråk för vård och omsorg: Slutrapport2011Rapport (Annet (populærvitenskap, debatt, mm))
    Abstract [sv]

    Sammanfattning

    Ett tillgängligt och använt nationellt fackspråk ska bidra till en god och säker vård och omsorg. Det ska även medverka till att kvaliteten och resultaten på området ska kunna följas upp och jämföras på ett mer effektivt sätt. Slutrapporten presenterar resultatet av projektet Nationellt fackspråk för vård och omsorg samt förslag till förvaltning och utveckling.

    Resultatet

    Resultatet innefattar bland annat att det internationella begreppssystemet Snomed CT är översatt till svenska och att det är förberett för förvaltning och distribution. Socialstyrelsen har även tagit fram och testat metoder för förvaltning och utveckling av det nationella fackspråket i sin helhet. Därtill har representanter för målgrupperna informerats och fått kunskap.

    Rapporten innehåller en utförlig beskrivning av det nationella fackspråkets sammantagna innehåll: Socialstyrelsens termbank, klassifikationer och kodverk, den svenska versionen av Snomed CT, metoder för utveckling och förvaltning samt regler för användning.

    Förvaltning, införande och resursbehov

    I rapporten finns förslag till hur hela det nationella fackspråket kan tas omhand av Socialstyrelsen och hur det kan införas i vården och omsorgen. Projektets övergång till en långsiktigt hållbar organisation kräver resurser. Därför redogör rapporten för det förväntade resursbehovet för förvaltning och utveckling. Bland annat föreslås en treårig utbildningsinsats samt stimulansbidrag för införande.

    Krav på styrning, samordning och förtydligat ansvar

    Rapporten betonar behovet av en samlad och medveten styrning av utvecklingen inom området. Socialstyrelsen vill ha en samordnande roll i utvecklingen och förvaltningen av det nationella fackspråket. Myndigheten föreslås få det initiala ansvaret för att utbilda användare och att driva frågor om det nationella fackspråket.

    Vidare vill Socialstyrelsen få ett uttalat mandat att samordna de nationella aktiviteter som drivs med koppling till Snomed CT. Rapporten pekar ut några särskilt prioriterade områden som myndigheten borde få i uppdrag att arbeta vidare inom.

    Kunskapsstyrning och normgivning

    En viktig slutsats i rapporten är att användningen av det nationella fackspråket behöver regleras för att målet om ökad säkerhet för klienter och patienter ska kunna uppnås. I dagsläget bedöms föreskrifter vara den metod som bäst kan garantera ett brett genomförande.

    Målgrupper för slutrapporten

    Slutrapporten riktar sig till beslutsfattare i kommuner och landsting, vård- och omsorgspersonal med särskilt intresse eller ansvar för dokumentationsfrågor och professionella organisationer. Den riktar sig också till terminologiansvariga i kommuner och landsting, IT-direktörer, IT-leverantörer samt aktörer inom den nationella strategin för eHälsa.

  • 215.
    Barua, Shaibal
    et al.
    Malardalen Univ, Sweden.
    Uddin Ahmed, Mobyen Uddin
    Malardalen Univ, Sweden.
    Ahlström, Christer
    Linköpings universitet, Institutionen för medicinsk teknik, Fysiologisk mätteknik. Linköpings universitet, Tekniska fakulteten. Swedish Natl Rd and Transport Res Inst VTI, SE-58195 Linkoping, Sweden.
    Begum, Shahina
    Malardalen Univ, Sweden.
    Automatic driver sleepiness detection using EEG, EOG and contextual information2019Inngår i: Expert systems with applications, ISSN 0957-4174, E-ISSN 1873-6793, Vol. 115, s. 121-135Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The many vehicle crashes that are caused by driver sleepiness each year advocates the development of automated driver sleepiness detection (ADSD) systems. This study proposes an automatic sleepiness classification scheme designed using data from 30 drivers who repeatedly drove in a high-fidelity driving simulator, both in alert and in sleep deprived conditions. Driver sleepiness classification was performed using four separate classifiers: k-nearest neighbours, support vector machines, case-based reasoning, and random forest, where physiological signals and contextual information were used as sleepiness indicators. The subjective Karolinska sleepiness scale (KSS) was used as target value. An extensive evaluation on multiclass and binary classifications was carried out using 10-fold cross-validation and leave-one-out validation. With 10-fold cross-validation, the support vector machine showed better performance than the other classifiers (79% accuracy for multiclass and 93% accuracy for binary classification). The effect of individual differences was also investigated, showing a 10% increase in accuracy when data from the individual being evaluated was included in the training dataset. Overall, the support vector machine was found to be the most stable classifier. The effect of adding contextual information to the physiological features improved the classification accuracy by 4% in multiclass classification and by and 5% in binary classification. (C) 2018 Elsevier Ltd. All rights reserved.

  • 216.
    Baud, Robert
    et al.
    Medical Informatics Division University Hospital of Geneva.
    Nyström, Mikael
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för medicinsk teknik, Medicinsk informatik.
    Borin, Lars
    Inst för svenska språket Göteborgs universitet.
    Ewans, Roger
    The Information Technology Research Institute University of Brighton.
    Schulz, Stefan
    Inst of Medical Biometry and Medical Informatics Albert-Ludwigs-Universität, Freiburg.
    Zweigenbaum, Pierre
    STIM/DSI Assistance Publique-Hopitaux de Paris.
    Interchanging Lexical information for a multilingual dictionary2005Inngår i: AMIA Annual Symposium Proceedings, Washington DC: AMIA Symposium; American Medical Informatics Association , 2005, s. 31-35Konferansepaper (Fagfellevurdert)
    Abstract [en]

    OBJECTIVE:

    To facilitate the interchange of lexical information for multiple languages in the medical domain. To pave the way for the emergence of a generally available truly multilingual electronic dictionary in the medical domain.

    METHODS:

    An interchange format has to be neutral relative to the target languages. It has to be consistent with current needs of lexicon authors, present and future. An active interaction between six potential authors aimed to determine a common denominator striking the right balance between richness of content and ease of use for lexicon providers.

    RESULTS:

    A simple list of relevant attributes has been established and published. The format has the potential for collecting relevant parts of a future multilingual dictionary. An XML version is available.

    CONCLUSION:

    This effort makes feasible the exchange of lexical information between research groups. Interchange files are made available in a public repository. This procedure opens the door to a true multilingual dictionary, in the awareness that the exchange of lexical information is (only) a necessary first step, before structuring the corresponding entries in different languages.

  • 217.
    Bayarri Portolés, Laia
    Linköpings universitet, Institutionen för medicinsk teknik.
    Lossles Compression of ECG signals: Performance Analysis in a Wireless Network2009Independent thesis Advanced level (degree of Master (Two Years)), 30 poäng / 45 hpOppgave
    Abstract [en]

    With the development of multimedia and digital systems there is a need toreduce the cost of storage and transmission of information. The storage requirementsfor long signals like 24-hour heart monitoring are very large sosignal compression is often employed. The cost reduction achieved throughcompression leads to a reduction in the amount of data that represents theinformation. At the same time, once the decompression procedure is done,the resulting signal must contain enough detail for the cardiologist to be ableto identify irregularities. \Lossy"compressors may hide such details, whereas\lossless" compressor preserves the signal exactly as captured.

    This thesis researches into the performance of several lossless compressionalgorithms widely used for image coding. The dierent compressiontechniques are evaluated not only in terms of compression ratio and compressionand decompression bandwidths achieved but also based on theirperformance when the compressed data must be sent over any of the availablewireless networks.

    This thesis documents the work of a master's degree project carried outduring the spring of 2009. The project is part of a research project withinthe Department of Biomedical Engineering at Linkopings Universitet. Theproject aims at researching and developing a data compression model fortransmitting medical signals. The model should be feasible and it shouldprove the advantages of data compression. These implementations are intendedto be used within a larger system allowing a patient to transmitmedical data from a remote location.

  • 218. Bech Hanssen, Odd
    et al.
    Wranne, Bengt
    Linköpings universitet, Hälsouniversitetet. Linköpings universitet, Institutionen för medicin och vård, Klinisk fysiologi. Östergötlands Läns Landsting, Hjärtcentrum, Fysiologiska kliniken.
    Ask, Per
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för medicinsk teknik, Fysiologisk mätteknik.
    Loyd, Dan
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för konstruktions- och produktionsteknik, Mekanisk värmeteori och strömningslära.
    Caidahl, Kenneth
    The net pressure gradients after pressure recovery can be predicted by Doppler in aortic bileaflet prostheses.2001Inngår i: American Society of Echocardiography,2001, 2001Konferansepaper (Fagfellevurdert)
  • 219. Bech-Hansen, Odd
    et al.
    Caidahl, Kenneth
    Wallentin, Ingemar
    Ask, Per
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för medicinsk teknik, Fysiologisk mätteknik.
    Wranne, Bengt
    Linköpings universitet, Hälsouniversitetet. Linköpings universitet, Institutionen för medicin och vård, Klinisk fysiologi. Östergötlands Läns Landsting, Hjärtcentrum, Fysiologiska kliniken.
    Assessment of effective orifice area of prosthetic aortic valves with Doppler echocardiography: An in vivo and in vitro study2001Inngår i: Journal of Thoracic and Cardiovascular Surgery, ISSN 0022-5223, E-ISSN 1097-685X, Vol. 122, nr 2, s. 287-295Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Objectives: We sought to evaluate the Doppler assessment of effective orifice area in aortic prosthetic valves. The effective orifice area is a less flow-dependent parameter than Doppler gradients that is used to assess prosthetic valve function. However, in vivo reference values show a pronounced spread of effective orifice area and smaller orifices than expected compared with the geometric area. Methods: Using Doppler echocardiography, we studied patients who received a bileaflet St Jude Medical valve (n = 75, St Jude Medical, Inc, St Paul, Minn) or a tilting disc Omnicarbon valve (n = 46, Medical CV, Incorporated, Inver Grove Heights, Minn). The prosthetic valves were also investigated in vitro in a steady flow model with Doppler and catheter measurements in the different orifices. The effective orifice area was calculated according to the continuity equation. Results: In vivo, there was a wide distribution with the coefficient of variation (SD/mean ╫ 100%) for different valve sizes ranging from 21% to 39% in the St Jude Medical valve and from 25% to 33% in the Omnicarbon valve. The differences between geometric orifice area and effective orifice area in vitro were 1.26 ▒ 0.41 cm2 for St Jude Medical and 1.17 ▒ 0.38 cm2 for Omnicarbon valves. The overall effective orifice areas and peak catheter gradients were similar: 1.35 ▒ 0.37 cm2 and 25.9 ▒ 16.1 mm Hg for St Jude Medical and 1.46 ▒ 0.49 cm2 and 24.6 ▒ 17.7 mm Hg for Omnicarbon. However, in St Jude Medical valves, more pressure was recovered downstream, 11.6 ▒ 6.3 mm Hg versus 3.4 ▒ 1.6 mm Hg in Omnicarbon valves (P = .0001). Conclusions: In the patients, we found a pronounced spread of effective orifice areas, which can be explained by measurement errors or true biologic variations. The in vitro effective orifice area was small compared with the geometric orifice area, and we suspect that nonuniformity in the spatial velocity profile causes underestimation. The St Jude Medical and Omnicarbon valves showed similar peak catheter gradients and effective orifice areas in vitro, but more pressure was recovered in the St Jude Medical valve. The effective orifice area can therefore be misleading in the assessment of prosthetic valve performance when bileaflet and tilting disc valves are compared.

  • 220. Bech-Hanssen, O
    et al.
    Caidahl, K
    Wallentin, I
    Brandberg, J
    Wranne, Bengt
    Linköpings universitet, Hälsouniversitetet. Linköpings universitet, Institutionen för medicin och hälsa, Klinisk fysiologi. Östergötlands Läns Landsting, Hjärtcentrum, Fysiologiska kliniken.
    Ask, Per
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för medicinsk teknik, Fysiologisk mätteknik.
    Aortic prosthetic valve design and size: Relation to Doppler echocardiographic findings and pressure recovery - An in vitro study2000Inngår i: Journal of the American Society of Echocardiography, ISSN 0894-7317, E-ISSN 1097-6795, Vol. 13, nr 1, s. 39-50Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The extent to which Doppler echocardiography information can be used in the assessment of prosthesis hemodynamic performance is still controversial. The goals of our study were to assess the importance of valve design and size both on Doppler echocardiography findings and on pressure recovery in a fluid mechanics model. We performed Doppler and catheter measurements in the different orifices of the bileaflet St Jude (central and side orifices), the monoleaflet Omnicarbon (major and minor orifices), and the stented Biocor porcine prosthesis. Net pressure gradients were predicted from Doppler flow velocities, assuming either independence or dependence of valve size. The peak Doppler estimated gradients (mean +/- SD for sizes 21 to 27) were 21 +/- 10.3 rum Hg for St Jude, 18 +/- 9.3 mm Hg for Omnicarbon, and 37 +/- 14.5 mm Hg for Biocor (P <.05 for St Jude and Omnicarbon vs Biocor). The pressure recovery (proportion of peak catheter pressure) was 53% +/- 8.6% for central-St Jude, 29% +/- 8.9% for side-St Jude, 20% +/- 5.6% for major-Omnicarbon, 23% +/- 7.4% for minor-Omnicarbon, and 18% +/- 3.6% for Biocor (P <.05 for central-St Jude and side-St Jude vs Omnicarbon and Biocor). Valve sizes (2) significantly influenced pressure recovery (y in percentage) (central-St Jude: y = 3.7x - 35.9, r = 0.88, P =.0001, major-Omnicarbon: y = 2.1x - 30.3, r = 0.85, P =.0001). By assuming dependence of valve size, Doppler was able to predict net pressure gradients in St Jude with a mean difference between net catheter and Doppler-predicted gradient of - 3.8 +/- 2.5 mm Hg. In conclusion, prosthetic value design and size influence the degree of pressure recovery, making Doppler gradients potentially misleading in both the assessment of hemodynamic performance and the comparison of one design with another. The preliminary results indicate that net gradient can be predicted from Doppler gradients,

  • 221. Bech-Hanssen, O
    et al.
    Caidahl, K
    Wallentin, I
    Brandberg, J
    Wranne, Bengt
    Linköpings universitet, Institutionen för medicin och vård, Klinisk fysiologi. Linköpings universitet, Hälsouniversitetet. Östergötlands Läns Landsting, Hjärt- och Medicincentrum, Fysiologiska kliniken US.
    Ask, Per
    Linköpings universitet, Institutionen för medicinsk teknik, Fysiologisk mätteknik. Linköpings universitet, Tekniska högskolan.
    Aortic prosthetic valve design and size: relation to Doppler echocardiographic findings and pressure recovery- an in vitro study.2000Inngår i: Journal of the American Society of Echocardiography, ISSN 0894-7317, E-ISSN 1097-6795, Vol. 13, nr 1, s. 39-50Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The extent to which Doppler echocardiography information can be used in the assessment of prosthesis hemodynamic performance is still controversial. The goals of our study were to assess the importance of valve design and size both on Doppler echocardiography findings and on pressure recovery in a fluid mechanics model. We performed Doppler and catheter measurements in the different orifices of the bileaflet St Jude (central and side orifices), the monoleaflet Omnicarbon (major and minor orifices), and the stented Biocor porcine prosthesis. Net pressure gradients were predicted from Doppler flow velocities, assuming either independence or dependence of valve size. The peak Doppler estimated gradients (mean +/- SD for sizes 21 to 27) were 21 +/- 10.3 mm Hg for St Jude, 18 +/- 9.3 mm Hg for Omnicarbon, and 37 +/- 14.5 mm Hg for Biocor (P <.05 for St Jude and Omnicarbon vs Biocor). The pressure recovery (proportion of peak catheter pressure) was 53% +/- 8.6% for central-St Jude, 29% +/- 8. 9% for side-St Jude, 20% +/- 5.6% for major-Omnicarbon, 23% +/- 7.4% for minor-Omnicarbon, and 18% +/- 3.6% for Biocor (P <.05 for central-St Jude and side-St Jude vs Omnicarbon and Biocor). Valve sizes (x) significantly influenced pressure recovery (y in percentage) (central-St Jude: y = 3.7x - 35.9, r = 0.88, P =.0001; major-Omnicarbon: y = 2.1x - 30.3, r = 0.85, P =.0001). By assuming dependence of valve size, Doppler was able to predict net pressure gradients in St Jude with a mean difference between net catheter and Doppler-predicted gradient of -3.8 +/- 2.5 mm Hg. In conclusion, prosthetic valve design and size influence the degree of pressure recovery, making Doppler gradients potentially misleading in both the assessment of hemodynamic performance and the comparison of one design with another. The preliminary results indicate that net gradient can be predicted from Doppler gradients.

  • 222.
    Bech-Hanssen, O.
    et al.
    Department of Clinical Physiology, Sahlgrenska University Hospital, SE-413 45 Göteborg, Sweden.
    Gjertsson, P.
    Gjertsson, P..
    Houltz, E.
    Department of Clinical Physiology, Sahlgrenska University Hospital, SE-413 45 Göteborg, Sweden.
    Wranne, Bengt
    Linköpings universitet, Hälsouniversitetet. Linköpings universitet, Institutionen för medicin och hälsa, Klinisk fysiologi. Östergötlands Läns Landsting, Hjärtcentrum, Fysiologiska kliniken.
    Ask, Per
    Linköpings universitet, Institutionen för medicinsk teknik, Fysiologisk mätteknik. Linköpings universitet, Tekniska högskolan.
    Loyd, Dan
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Mekanisk värmeteori och strömningslära.
    Caidahl, K.
    Caidahl, K..
    Net Pressure Gradients in Aortic Prosthetic Valves can be Estimated by Doppler2003Inngår i: Journal of the American Society of Echocardiography, ISSN 0894-7317, E-ISSN 1097-6795, Vol. 16, nr 8, s. 858-866Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Background: In aortic prosthetic valves, both the Doppler-estimated gradients and orifice areas are misleading in the assessment of hemodynamic performance. The parameter of major interest is the net pressure gradient after pressure recovery (PR). We, therefore, investigated, in vitro, our ability to predict the net pressure gradient and applied the formulas in a representative patient population with 2 different valve designs. Methods: We studied the St Jude Medical (SJM) standard valve (size 19-27) and SJM Biocor (size 21-27) in an in vitro steady-flow model with simultaneous Doppler-estimated pressure and catheter pressure measurements. Using echocardiography, we also studied patients who received the SJM (n = 66) and SJM Biocor (n = 45). Results: In the SJM, we observed PR both within the prosthesis and aorta, whereas in the SJM Biocor, PR was only present in the aorta. We estimated the PR within the valve and within the aorta separately from echocardiographic in vitro data, combining a regression equation (valve) with an equation on the basis of fluid mechanics theory (aorta). The difference between estimated and catheter-obtained net gradients (mean ± SD) was 0.6 ± 1.6 mm Hg in the SJM and - 0.2 ± 1.9 mm Hg in the SJM Biocor. When these equations were applied in vivo, we found that PR had an overall value of 57 ± 7% of the peak Doppler gradient in the SJM and 33 ± 9% in the SJM Biocor. Conclusions: The in vitro results indicate that it is possible to predict the net pressure gradient by Doppler in bileaflet and stented biologic valves. Our data indicate that important PR is also present in stented biologic valves.

  • 223.
    Behjat, Hamid
    Linköpings universitet, Institutionen för medicinsk teknik, Medicinsk informatik. Linköpings universitet, Tekniska högskolan.
    Statistical Parametric Mapping of fMRI data using Spectral Graph Wavelets2012Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    In typical statistical parametric mapping (SPM) of fMRI data, the functional data are pre-smoothed using a Gaussian kernel to reduce noise at the cost of losing spatial specificity. Wavelet approaches have been incorporated in such analysis by enabling an efficient representation of the underlying brain activity through spatial transformation of the original, un-smoothed data; a successful framework is the wavelet-based statistical parametric mapping (WSPM) which enables integrated wavelet processing and spatial statistical testing. However, in using the conventional wavelets, the functional data are considered to lie on a regular Euclidean space, which is far from reality, since the underlying signal lies within the complex, non rectangular domain of the cerebral cortex. Thus, using wavelets that function on more complex domains such as a graph holds promise. The aim of the current project has been to integrate a recently developed spectral graph wavelet transform as an advanced transformation for fMRI brain data into the WSPM framework. We introduce the design of suitable weighted and un-weighted graphs which are defined based on the convoluted structure of the cerebral cortex. An optimal design of spatially localized spectral graph wavelet frames suitable for the designed large scale graphs is introduced. We have evaluated the proposed graph approach for fMRI analysis on both simulated as well as real data. The results show a superior performance in detecting fine structured, spatially localized activation maps compared to the use of conventional wavelets, as well as normal SPM. The approach is implemented in an SPM compatible manner, and is included as an extension to the WSPM toolbox for SPM.

  • 224.
    Behm, Pascal
    Linköpings universitet, Institutionen för medicinsk teknik, Biomedicinsk instrumentteknik. Linköpings universitet, Tekniska högskolan. Institute for Medical ans Analytical Technologies, University of Northwestern Switzerland.
    Experimental set-up for near infrared fluorescence measurements during surgery2013Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [en]

    In case a tumour grows in a tissue close to the lymphatic system, biopsies of the first draining lymph nodes connected to the tumour, also known as sentinel lymph nodes, allow determining if the cancer has already metastasized. Lymph node mapping is used in oncology surgery to find the patients lymph nodes connected to the tumour. The fluorescence marker indocyanine green (ICG) has shown successful results to trace the lymph nodes and arise to replace the currently used radioactive tracers. Because the ICG fluorescence is in the near infrared region and not visible to the human eye, imaging systems are used to visualise the fluorescence. A preliminary spectroscopy measurement system was developed at the Department of Biomedical Engineering, Linköping University. The aim of this thesis was to develop a combined spectroscopy and imaging set-up for simultaneous recordings of ICG fluorescence and suggest further developments.

    The combined system consisted of a fibre-optical based spectroscopy system together with a camera imaging system. An optical phantom that mimicked breast tissue (μs = 4.66 mm-1) was developed for the measurements. Phantoms with different ICG concentrations of 6.45 μM, 64.5 μM and 645 μM simulated different concentrations of fluorescence dye in the lymph system. The set-up and the settings of the devices were adjusted to enable simultaneous measurements with both systems. The phantoms were solidified with agar to measure the fluorescence decay (photobleaching) of ICG. To simulate a lymph node deep in the tissue, a tube containing pure ICG was covered with different layer thicknesses of breast tissue-like phantom.

    Measurements at the same time with both systems were possible when the probe was positioned in an 80 degree angle with 5 mm distance relative to the phantom surface and the camera in 10 cm distance with a 30 degree angle. To visualise the ICG fluorescence emission with the excitation light (4 mW) and an integration time of 600 ms was necessary for the camera. Higher laser power caused saturation in the spectrometer. The spectroscopy measurements and camera images showed maximum fluorescence intensity at an optimal ICG concentration (10-16 μM) in the phantom. Also the photobleaching measurements showed to be dependent on the ICG concentration and associated with the optimal concentration. ICG concentrations equal and lower than the optimal concentration decayed with exposure to the excitation light. The fluorescence intensity of higher concentrations initially increased and decayed after reaching a maximum intensity when exposed to the excitation light. The detection depth in the simulated tissue was limited to 0.3 mm for spectroscopy. A detection depth of 2 mm was achieved with the camera while using the maximum excitation power of 50 mW and integration time of 700 ms.

    Simultaneous measurements were possible with the set-up on the same phantom. An optimal concentration of ICG was found for the developed phantom. The ICG fluorescence intensity was concentration dependent and showed a relatively slow photobleaching. The fibre-optical based spectroscopy system was able to measure low ICG emissions. Subtracting the background spectrum of surrounding tissue might increase the detection of weak ICG signals in depth. High excitation power and an increased integration time were needed to record ICG fluorescence emission with the camera. The obtained results allowed suggestions for the further improvement of set-up and its intraoperative use.

  • 225.
    Benosman, M. M.
    et al.
    Linköpings universitet, Institutionen för medicinsk teknik. Linköpings universitet, Tekniska fakulteten. Tlemcen Univ, Biomed Engn Dept, Tilimsen 13000, Algeria.
    Bereksi-Reguig, F.
    Tlemcen Univ, Algeria.
    Salerud, Göran
    Linköpings universitet, Institutionen för medicinsk teknik, Avdelningen för medicinsk teknik. Linköpings universitet, Tekniska fakulteten.
    STRONG REAL-TIME QRS COMPLEX DETECTION2017Inngår i: Journal of Mechanics in Medicine and Biology, ISSN 0219-5194, Vol. 17, nr 8, artikkel-id 1750111Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Heart rate variability (HRV) analysis is used as a marker of autonomic nervous system activity which may be related to mental and/or physical activity. HRV features can be extracted by detecting QRS complexes from an electrocardiogram (ECG) signal. The difficulties in QRS complex detection are due to the artifacts and noises that may appear in the ECG signal when subjects are performing their daily life activities such as exercise, posture changes, climbing stairs, walking, running, etc. This study describes a strong computation method for real-time QRS complex detection. The detection is improved by the prediction of the position of R waves by the estimation of the RR intervals lengths. The estimation is done by computing the intensity of the electromyogram noises that appear in the ECG signals and known here in this paper as ECG Trunk Muscles Signals Amplitude (ECG-TMSA). The heart rate (HR) and ECG-TMSA increases with the movement of the subject. We use this property to estimate the lengths of the RR intervals. The method was tested using famous databases, and also with signals acquired when an experiment with 17 subjects from our laboratory. The obtained results using ECG signals from the MIT-Noise Stress Test Database show a QRS complex detection error rate (ER) of 9.06%, a sensitivity of 95.18% and a positive prediction of 95.23%. This method was also tested against MIT-BIH Arrhythmia Database, the result are 99.68% of sensitivity and 99.89% of positive predictivity, with ER of 0.40%. When applied to the signals obtained from the 17 subjects, the algorithm gave an interesting result of 0.00025% as ER, 99.97% as sensitivity and 99.99% as positive predictivity.

  • 226.
    Benosman, Mourad
    et al.
    Linköpings universitet, Institutionen för medicinsk teknik. Linköpings universitet, Tekniska högskolan. Tlemcen University, Algeria.
    Bereksi-reguig, Fethi
    Tlemcen University, Algeria.
    Salerud, Göran
    Linköpings universitet, Institutionen för medicinsk teknik, Biomedicinsk instrumentteknik. Linköpings universitet, Tekniska högskolan.
    Analysis of ECG-trunk muscle signal amplitude and heart rate relationship2013Inngår i: Journal of Medical Engineering & Technology, ISSN 0309-1902, E-ISSN 1464-522X, Vol. 37, nr 7, s. 449-455Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The objective of this paper is to investigate if bioelectrical signals, generated from trunk muscles identified in an electrocardiogram (ECG) signal presented in this paper as ECG-Trunk Muscles Signals amplitude (Ecg-TMSA) are correlated with Heart rate (HR) during different levels of physical activity and also if Ecg-TMSA is not influenced by mental activity. HR and Ecg-TMSA were derived from ECG in 14 subjects when walking and jogging at different treadmill velocities from 4–10 (km h−1). The mean relationship for all 14 subjects was HR = (42.3 ± 0.2) + (45.3 ± 2.8) Ecg-TMSA, r2 = 0.91. The result of one individual data points example for a 21 min experiment was (r2 = 0.93, p < 0.0001, n = 336). The obtained results show a linear relationship between Ecg-TMSA and HR. Moreover, the Ecg-TMSA was not affected by mental activity

  • 227.
    Benosman, Mourad
    et al.
    Abou Bekr Belkaid university, Tlemcen, Algeria.
    Bereksi-reguig, Fethi
    Abou Bekr Belkaid university, Tlemcen, Algeria.
    Salerud, Göran
    Linköpings universitet, Institutionen för medicinsk teknik, Biomedicinsk instrumentteknik. Linköpings universitet, Tekniska högskolan.
    Distingush physical activity from mental stress analyzing ECG signals with overlayed non cardiac muscle activity2012Inngår i: BIOMEIC'12, 2012Konferansepaper (Annet vitenskapelig)
  • 228.
    Benosman, Mourad
    et al.
    Abou Bekr Belkaid university, Tlemcen, Algeria.
    Salerud, Göran
    Linköpings universitet, Institutionen för medicinsk teknik, Biomedicinsk instrumentteknik. Linköpings universitet, Tekniska högskolan.
    Bereksi-reguig, Fethi
    Abou Bekr Belkaid university, Tlemcen, Algeria.
    Measuring muscle activity with ECG electrodes to distinguish physical activity from mental stress2012Konferansepaper (Annet vitenskapelig)
  • 229.
    Berg Andersen, Per
    et al.
    University of Bergen, Norway .
    Babic, Ankica
    Linköpings universitet, Institutionen för medicinsk teknik, Medicinsk informatik. Linköpings universitet, Tekniska högskolan. University of Bergen, Norway .
    Self-reporting for Bipolar Patients through Smartphone2014Inngår i: IFMBE Proceedings / [ed] Laura M. Roa Romero, Springer, 2014, Vol. 41, s. 1358-1361Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Self-reporting of symptoms is widely used and validated in the field of psychiatry, also in the context of bipolar disorder. This paper presents work on a self-reporting system for bipolar patients using a smartphone to gather data from the patient, which is communicated to a server via a secure connection. The data is presented in a web application to a patient for his/hers self-monitoring, and to medical personnel associated with the treatment of the patient. The work described here is part of an ongoing system development and gives insights into the field research and motivation for choosing Life Charting Methodology as a structural element. Leaning on such well accepted and validated therapeutic tools should secure validity and feasibility of the final system that would appear to patients as familiar and easy to use. Consequently, the application is expected to be directly understandable to everyone involved in the treatment. Programming solutions will capture the essence, but will be adjusted to the electronic environment which will be validated for its correctness and user-friendliness.

  • 230.
    Bergenholm, Linnéa
    Linköpings universitet, Institutionen för medicinsk teknik. Linköpings universitet, Hälsouniversitetet.
    Modeling as a Tool to Support Self-Management of Type 1 Diabetes2013Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Type 1 diabetes (T1D) is an auto-immune disease characterized by insulin-deficiency. Insulin is a metabolic hormone that is involved in lowering blood glucose (BG) levels in order to control BG level to a tight range. In T1D this glycemic control is lost, causing chronic hyperglycemia (excess glucose in blood stream). Chronic hyperglycemia damages vital tissues. Therefore, glycemic control must be restored.

    A common therapy for restoring glycemic control is intensive insulin therapy, where the missing insulin is replaced with regular insulin injections. When dosing this compensatory insulin many factors that affect glucose metabolism must be considered. Linkura is a company that has developed tools for monitoring the most important factors, which are meals and exercise. In the Linkura meal and exercise tools, the nutrition content in meals and the calorie consumption during exercise are estimated. Another tool designed to aid control of BG is the bolus calculator. Bolus calculators use input of BG level, carbohydrate intake, and insulin history to estimate insulin need. The accuracy of these insulin bolus calculations suffer from two problems. First, errors occur when users inaccurately estimate the carbohydrate content in meals. Second, exercise is not included in bolus calculations. To reduce these problems, it was suggested that the Linkura web tools could be utilized in combination with a bolus calculator.

    For this purpose, a bolus calculator was developed. The bolus calculator was based on existing models that utilize clinical parameters to relate changes in BG levels to meals, insulin, and exercise stimulations. The bolus calculator was evaluated using data collected from Linkura's web tools. The collected data showed some inconsistencies which cannot be explained by any model.  The performance of the bolus calculator in predicting BG levels using general equations to derive the clinical parameters was inadequate. Performance was increased by adopting an update-algorithm where the clinical parameters were updated daily using previous data. Still, better model performance is prefered for use in a bolus calculator.  

    The results show potential in developing bolus calculator tools combined with the Linkura tools. For such bolus calculator, further evaluation on modeling long-term exercise and additional safety features minimizing risk of hypoglycemia are required.

  • 231.
    Bergnéhr, Leo
    Linköpings universitet, Institutionen för medicinsk teknik, Medicinsk informatik. Linköpings universitet, Tekniska högskolan.
    Segmentation and Alignment of 3-D Transaxial Myocardial Perfusion Images and Automatic Dopamin Transporter Quantification2008Independent thesis Basic level (professional degree), 20 poäng / 30 hpOppgave
    Abstract [sv]

    Nukleärmedicinska bilder som exempelvis SPECT (Single Photon Emission Tomogra-phy) är en bildgenererande teknik som ofta används i många applikationer vid mätning av fysiologiska egenskaper i den mänskliga kroppen. En vanlig sorts undersökning som använder sig av SPECT är myokardiell perfusion (blodflöde i hjärtvävnaden), som ofta används för att undersöka t.ex. en möjlig hjärtinfarkt. För att göra det möjligt för läkare att ställa en kvalitativ diagnos baserad på dessa bilder, måste bilderna först segmenteras och roteras av en biomedicinsk analytiker. Detta utförs på grund av att hjärtat hos olika patienter, eller hos patienter vid olika examinationstillfällen, inte är lokaliserat och roterat på samma sätt, vilket är ett väsentligt antagande av läkaren vid granskning

    av bilderna. Eftersom olika biomedicinska analytiker med olika mängd erfarenhet och expertis roterar bilderna olika uppkommer variation av de slutgiltiga bilder, vilket ofta kan vara ett problem vid diagnostisering.

    En annan sorts nukleärmedicinsk undersökning är vid kvantifiering av dopaminreceptorer i de basala ganglierna i hjärnan. Detta utförs ofta på patienter som visar symptom av Parkinsons sjukdom, eller liknande sjukdomar. För att kunna bestämma graden av sjukdomen används ofta ett utförande för att räkna ut olika kvoter mellan områden runt dopaminreceptorerna. Detta är ett tröttsamt arbete för personen som utför kvantifieringen och trots att de insamlade bilderna är tredimensionella, utförs kvantifieringen allt för ofta endast på en eller flera skivor av bildvolymen. I likhet med myokardiell perfusionsundersökningar är variation mellan kvantifiering utförd av olika personer en möjlig felkälla.

    I den här rapporten presenteras en ny metod för att automatiskt segmentera hjärtats vänstra kammare i SPECT-bilder. Segmenteringen är baserad på en intensitetsinvariant lokal-fasbaserad lösning, vilket eliminerar svårigheterna med den i myokardiella perfusionsbilder ofta varierande intensiteten. Dessutom används metoden för att uppskatta vinkeln hos hjärtats vänstra kammare. Efter att metoden sedan smått justerats används den som ett förslag på ett nytt sätt att automatiskt kvantifiera dopaminreceptorer i de basala ganglierna, vid användning av den radioaktiva lösningen DaTSCAN.

  • 232.
    Bergquist, Urban
    et al.
    Inst för medicinsk teknik Linköpings universitet.
    Babic, Ankica
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för medicinsk teknik, Medicinsk informatik.
    Aspects of certainty in patient classification using a Health-related Quality-of-Life instrument in inflammatory bowel disease1999Inngår i: AMIA99,1999, Philadelphia: Hanley & Belfus Inc , 1999, s. 202-Konferansepaper (Fagfellevurdert)
  • 233.
    Bergqvist, Niclas
    et al.
    Linköpings universitet, Institutionen för medicinsk teknik. Linköpings universitet, Tekniska fakulteten.
    Nyman, Elin
    Linköpings universitet, Institutionen för medicinsk teknik, Avdelningen för medicinsk teknik. Linköpings universitet, Tekniska fakulteten. AstraZeneca RandD, Sweden.
    Cedersund, Gunnar
    Linköpings universitet, Institutionen för medicinsk teknik, Avdelningen för medicinsk teknik. Linköpings universitet, Tekniska fakulteten. Linköpings universitet, Institutionen för klinisk och experimentell medicin. Linköpings universitet, Medicinska fakulteten.
    Stenkula, Karin G.
    Lund University, Sweden.
    A systems biology analysis connects insulin receptor signaling with glucose transporter translocation in rat adipocytes2017Inngår i: Journal of Biological Chemistry, ISSN 0021-9258, E-ISSN 1083-351X, Vol. 292, nr 27, s. 11206-11217Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Type 2 diabetes is characterized by insulin resistance, which arises from malfunctions in the intracellular insulin signaling network. Knowledge of the insulin signaling network is fragmented, and because of the complexity of this network, little consensus has emerged for the structure and importance of the different branches of the network. To help overcome this complexity, systems biology mathematical models have been generated for predicting both the activation of the insulin receptor (IR) and the redistribution of glucose transporter 4 (GLUT4) to the plasma membrane. Although the insulin signal transduction between IR and GLUT4 has been thoroughly studied with modeling and time-resolved data in human cells, comparable analyses in cells from commonly used model organisms such as rats and mice are lacking. Here, we combined existing data and models for rat adipocytes with new data collected for the signaling network between IR and GLUT4 to create a model also for their interconnections. To describe all data (amp;gt;140 data points), the model needed three distinct pathways from IR to GLUT4: (i) via protein kinase B (PKB) and Akt substrate of 160 kDa (AS160), (ii) via an AS160-independent pathway from PKB, and (iii) via an additional pathway from IR, e.g. affecting the membrane constitution. The developed combined model could describe data not used for training the model and was used to generate predictions of the relative contributions of the pathways from IR to translocation of GLUT4. The combined model provides a systems-level understanding of insulin signaling in rat adipocytes, which, when combined with corresponding models for human adipocytes, may contribute to model-based drug development for diabetes.

  • 234.
    Bergstrand, Sara
    et al.
    Linköpings universitet, Institutionen för medicin och hälsa, Avdelningen för omvårdnad. Linköpings universitet, Hälsouniversitetet.
    Källman, Ulrika
    Linköpings universitet, Institutionen för medicin och hälsa, Avdelningen för omvårdnad. Linköpings universitet, Hälsouniversitetet. Department of Dermatology, Södra Älvsborgs Sjukhus, Borås, Sweden.
    Ek, Anna-Christina
    Linköpings universitet, Institutionen för medicin och hälsa, Avdelningen för omvårdnad. Linköpings universitet, Hälsouniversitetet. Östergötlands Läns Landsting, Närsjukvården i centrala Östergötland, Akutkliniken.
    Lindberg, Lars-Göran
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för medicinsk teknik, Fysiologisk mätteknik.
    Engström, Maria
    Linköpings universitet, Institutionen för medicin och hälsa, Avdelningen för radiologiska vetenskaper. Linköpings universitet, Hälsouniversitetet. Linköpings universitet, Centrum för medicinsk bildvetenskap och visualisering, CMIV.
    Sjöberg, Folke
    Linköpings universitet, Institutionen för klinisk och experimentell medicin, Avdelningen för kliniska vetenskaper. Linköpings universitet, Hälsouniversitetet. Östergötlands Läns Landsting, Sinnescentrum, Hand- och plastikkirurgiska kliniken US. Östergötlands Läns Landsting, Sinnescentrum, Anestesi- och intensivvårdskliniken US.
    Lindgren, Margareta
    Linköpings universitet, Institutionen för medicin och hälsa, Avdelningen för omvårdnad. Linköpings universitet, Hälsouniversitetet.
    Pressure-induced vasodilation and reactive hyperemia at different depths in sacral tissue under clinically relevant conditions2014Inngår i: Microcirculation, ISSN 1073-9688, E-ISSN 1549-8719, Vol. 21, nr 8, s. 761-771Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    OBJECTIVE: To characterize pressure-induced vasodilatation and reactive hyperemia at different sacral tissue depths in different populations under clinically relevant pressure exposure.

    METHODS: Forty-two subjects (< 65 years), 38 subjects (≥ 65 years), and 35 patients (≥ 65 years) participated. Interface pressure, skin temperature, and blood flow at tissue depths of 1 mm, 2 mm, and 10 mm (using laser Doppler flowmetry and photoplethysmography) were measured in the sacral tissue before, during, and after load in a supine position.

    RESULTS: pressure-induced vasodilatation and reactive hyperemia were observed at three tissue depths. At 10 mm depth, the proportion of subjects with a lack of pressure-induced vasodilatation was higher compared to superficial depths. The patients had higher interface pressure during load than the healthy individuals, but there were no significant differences in blood flow. Twenty-nine subjects in all three study groups were identified with a lack of pressure-induced vasodilatation and reactive hyperemia.

    CONCLUSIONS: pressure-induced vasodilatation and reactive hyperemia can be measured at different tissue depths. A lack of these responses was found in healthy individuals as well as in patients indicating an innate susceptibility in some individuals, and are potential important factors to evaluate in order to better understand the etiology of pressure ulcers.

  • 235.
    Bergstrand, Sara
    et al.
    Linköpings universitet, Hälsouniversitetet. Linköpings universitet, Institutionen för medicin och hälsa, Omvårdnad.
    Lindberg, Lars-Göran
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för medicinsk teknik, Fysiologisk mätteknik.
    Ek, Anna-Christina
    Linköpings universitet, Hälsouniversitetet. Linköpings universitet, Institutionen för medicin och hälsa, Omvårdnad. Östergötlands Läns Landsting, Närsjukvården i centrala Östergötland, Akutkliniken.
    Lindgren, Margareta
    Linköpings universitet, Hälsouniversitetet. Linköpings universitet, Institutionen för medicin och hälsa, Omvårdnad.
    Blood flow at different depth in the tissue measured with PPG and laser Doppler technique2008Inngår i: Third Congress of the World Unionof Wound Healing Societies,2008, 2008, s. 31-31Konferansepaper (Annet vitenskapelig)
    Abstract [en]

       

  • 236.
    Bergstrand, Sara
    et al.
    Linköpings universitet, Institutionen för medicin och hälsa, Omvårdnad. Linköpings universitet, Hälsouniversitetet.
    Lindberg, Lars-Göran
    Linköpings universitet, Institutionen för medicinsk teknik, Fysiologisk mätteknik. Linköpings universitet, Tekniska högskolan.
    Ek, Anna-Christina
    Linköpings universitet, Institutionen för medicin och hälsa, Omvårdnad. Linköpings universitet, Hälsouniversitetet. Östergötlands Läns Landsting, Närsjukvården i centrala Östergötland, Akutkliniken.
    Lindén, Maria
    Mälardalen University, Västerås, Sweden.
    Lindgren, Margareta
    Linköpings universitet, Institutionen för medicin och hälsa, Omvårdnad. Linköpings universitet, Hälsouniversitetet.
    Blood flow measurements at different depths using photoplethysmography and laser Doppler techniques2009Inngår i: Skin research and technology, ISSN 0909-752X, E-ISSN 1600-0846, Vol. 15, nr 2, s. 139-147Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Background/purpose: This study has evaluated a multi-parametric system combining laser Doppler flowmetry and photoplethysmography in a single probe for the simultaneous measurement of blood flow at different depths in the tissue. This system will be used to facilitate the understanding of pressure ulcer formation and in the evaluation of pressure ulcer mattresses.

    Methods: The blood flow in the tissue over the sacrum was measured before, during and after loading with 37.5 mmHg, respectively, 50.0 mmHg. The evaluation of the system consisted of one clinical part, and the other part focusing on the technicalities of the probe prototype.

    Results: An increase in blood flow while loading was the most common response, but when the blood flow decreased during loading it was most affected at the skin surface and the blood flow responses may be different due to depths of measurement. Reactive hyperaemia may occur more frequently in the superficial layers of the tissue.

    Conclusion: The study showed that the new system is satisfactory for measuring tissue blood flow at different depths. The laser Doppler complements the photoplethysmography, and further development of the system into a thin flexible probe with the ability to measure a larger area is required.

  • 237.
    Bergstrand, Sara
    et al.
    Linköpings universitet, Institutionen för medicin och hälsa, Omvårdnad. Linköpings universitet, Hälsouniversitetet.
    Lindberg, Lars-Göran
    Linköpings universitet, Institutionen för medicinsk teknik. Linköpings universitet, Hälsouniversitetet.
    Lindén, Maria
    n/a.
    Ek, Anna-Christina
    Linköpings universitet, Institutionen för medicin och hälsa, Omvårdnad. Linköpings universitet, Hälsouniversitetet.
    Länne, Toste
    Linköpings universitet, Institutionen för medicin och hälsa. Linköpings universitet, Hälsouniversitetet.
    Lindgren, Margareta
    Linköpings universitet, Institutionen för medicin och hälsa, Omvårdnad. Linköpings universitet, Hälsouniversitetet.
    Tissue blood flow responses to external pressure in the sacral region using PPG and laser Doppler technique.2009Inngår i: European Pressure Ulcer Advisory Panels, Amsterdam., 2009Konferansepaper (Fagfellevurdert)
  • 238.
    Bergstrand, Sara
    et al.
    Linköpings universitet, Institutionen för medicin och hälsa, Avdelningen för omvårdnad. Linköpings universitet, Medicinska fakulteten.
    Morales, Maria-Aurora
    CNR Inst Clin Physiol, Italy.
    Coppini, Giuseppe
    CNR Inst Clin Physiol, Italy.
    Larsson, Marcus
    Linköpings universitet, Institutionen för medicinsk teknik, Avdelningen för medicinsk teknik. Linköpings universitet, Tekniska fakulteten.
    Strömberg, Tomas
    Linköpings universitet, Institutionen för medicinsk teknik, Avdelningen för medicinsk teknik. Linköpings universitet, Tekniska fakulteten.
    The relationship between forearm skin speed-resolved perfusion and oxygen saturation, and finger arterial pulsation amplitudes, as indirect measures of endothelial function2018Inngår i: Microcirculation, ISSN 1073-9688, E-ISSN 1549-8719, Vol. 25, nr 2, artikkel-id e12422Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Objective: Endothelial function is important for regulating peripheral blood flow to meet varying metabolic demands and can be measured indirectly during vascular provocations. In this study, we compared the PAT finger response (EndoPAT) after a 5-minutes arterial occlusion to that from forearm skin comprehensive microcirculation analysis (EPOS). Methods: Measurements in 16 subjects with varying cardiovascular risk factors were carried out concurrently with both methods during arterial occlusion, while forearm skin was also evaluated during local heating. Results: Peak values for EPOS skin Perf(conv) and speed-resolved total perfusion after the release of the occlusion were significantly correlated to the EndoPAT RHI (rho =.68, P = .007 and rho =.60, P = .025, respectively), mainly due to high-speed blood flow. During local heating, EPOS skin oxygen saturation, SO2, was significantly correlated to RHI (rho = .62, P =.043). This indicates that SO2 may have diagnostic value regarding endothelial function. Conclusions: We have demonstrated for the first time a significant relationship between forearm skin microcirculatory perfusion and oxygen saturation and finger PAT. Both local heating and reactive hyperemia are useful skin provocations. Further studies are needed to understand the precise regulation mechanisms of blood flow and oxygenation during these tests.

  • 239.
    Bergström, Madeleine
    Linköpings universitet, Institutionen för medicinsk teknik.
    Skin dose measurement during radiation therapy of mastectomy patients using GafChromicTM EBT3 films.2017Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

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

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

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

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

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

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

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

  • 240.
    Berntsen, Eirik
    et al.
    University of Bergen, Norway.
    Babic, Ankica
    Linköpings universitet, Institutionen för medicinsk teknik, Medicinsk informatik. Linköpings universitet, Tekniska högskolan. University of Bergen, Norway.
    Cherry: mobile application for children with cancer2013Inngår i: MEDINFO 2013: proceedings of the 14th World Congress on Medical and Health Informatics / [ed] Christoph Ulrich Lehmann, Elske Ammenwerth, Christian Nøhr, IOS Press, 2013, s. 1168-Konferansepaper (Annet vitenskapelig)
    Abstract [en]

    The Cherry project seeks to address the information needs of young cancer patients, their parents, and health care providers. It aims at helping the patients to understand various aspects of their disease and treatment, and allow them to assess and record their disease related quality of life. It uses elements of social media to offer a meeting point with the physician and peers. Information is presented in a way that is both understandable and appealing to young children in school age and adolescents. Preschool children will be studied as a separate user group to address their needs and possibilities to meet them. The Cherry system wants to utilize Internet and mobile technologies to benefit patient outcome.

  • 241.
    Berntsen, Eirik
    et al.
    University of Bergen, Norway.
    Babic, Ankica
    Linköpings universitet, Institutionen för medicinsk teknik. Linköpings universitet, Tekniska högskolan. Univeristy of Bergen, Norway.
    Information System for Postmarket Surveillance of Total Joint Prostheses2015Inngår i: 16th Nordic-Baltic Conference on Biomedical Engineering / [ed] Henrik Mindedal ; Mikael Persson, Springer, 2015, s. 24-27Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Storage, integration and presentation of clinical data is an important aspect of any modern medical research. The Biomaterials research group at the Haukeland University Hospital uses both their own locally generated clinical data and external registry data to examine explanted joint implants. As a solution to this challenge, a system prototype was developed that would enable further integration of these information systems into a multi-user environment.

    The system allows importing registry data and matching it with local data, viewing and editing of this information and exporting the integrated data for further statistical analysis. An evaluation consisting of both user testing and heuristic evaluation was carried out and generated constructive feedback.

    The prototype demonstrates the feasibility of combining these data sources in a single database and the future possibility of exposing parts of this information to external users through a web application.

    Future integration of external sources could improve the information management of biobank data for postmarket surveillance of medical devices.

  • 242.
    Berntsson, Linn
    Linköpings universitet, Institutionen för medicinsk teknik.
    Evaluation of cognitive workload using EEG: Investigation of how sensory feedback improves function of osseo-neuromuscular upper limb prostheses2019Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    The e-OPRA Implant System (Integrum AB, Sweden) is a system which employs permanently accessible implantable neuromuscular electrodes in combination with osseointegrated attachment of the prosthesis to the skeleton, in order to create a more natural control of advanced robotic upper-limb prostheses. The system enables the possibility of sensory feedback, via a cuff electrode to the ulnar nerve which allows for direct neurostimulation of the nerve.

    This work proposes a method using electroencephalography (EEG) to quantitatively evaluate the cognitive workload of a person controlling a prosthesis, and how said workload changes when sensory feedback is enabled. Based on previous studies on EEG and cognitive workload, the proposed methods include collecting EEG data from subjects who are performing a grasping task while listening to a selection of sounds and counting the number of times a specific tone is presented. The data is analysed using both event related potentials (ERPs) as well as spectral analysis.

    The method was used in a trial run consisting of two healthy subjects, and one transhumeral amputee implanted with the e-OPRA system. Although the subject group was not large enough to draw any statistical conclusions, the trial run and the results from it suggest that the methods could be used in a larger study to evaluate the cognitive workload of amputees implanted with the e-OPRA system.

  • 243.
    Bhat, Danish
    Linköpings universitet, Institutionen för medicinsk teknik.
    Image Registration and Analysis within quantitative MRI to improve estimation of brain parenchymal fraction2016Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    In certain neuro-degenerative diseases likemultiple sclerosis (MS), the rate of brain atrophy can be measured by monitoring the brain parenchymal fraction (BPF) in such patients. The BPF is defined as the ratio of brain parenchymal volume (BPV, defined as the total volume of gray matter tissue, white matter tissue and other unidentified tissue) and intracranial volume (ICV, the total volume of the skull). It can be represented by the formula in equation 1:

    A complication with this measure is that the BPF is affected by the presence of edema in the brain, which leads to swelling and hence may obscure the true rate of brain atrophy. This leads to uncertainty when establishing “normal values” of BPF when analyzing different magnetic resonance imaging (MRI) scans of the same patient. Another problem is that different MRI scans of the same patient cannot be compared directly, due to the fact that the head of the patient will be in a different position for every scan.

    The SyMRI software used in this master thesis has the functionality to perform brain tissue characterization and measurement of brain volume, given a number of MR images of a patient. Using tissue properties such as longitudinal relaxation time (T1), transverse relaxation time (T2) and proton density (PD), each voxel in a volume can be classified to belong to a certain tissue type. From these measurements, the intracranial volume, brain volume, white matter, gray matter and cerebrospinal fluid volumes can easily be estimated.

    In this master thesis, the BPF of several patients were analyzed based on quantitative MRI (qMRI) images, in order to identify the change of BPF due to the presence of edema over time. Volumes obtained from the same patients at different time points were aligned (registered), such that the BPF can be easily compared between years. A correlation analysis between the BPF and R1, R2 and PD was performed (R1 is the longitudinal relaxation rate defined as 1/T1 relaxation time and R2 Is transverse relaxation rate defined as 1/T2 relaxation time) to investigate if any of these variables can explain the change in BPF.

    The results show that due to image registration, and removing some of the slices from the top and bottom of the head, the BPF of the patients was corrected to a certain extent. The change in the mean BPF of each patient over four years was less than 1% post registration and slice removal. However, the decrease in standard deviation was between 6.9% to 52% after registration and removing of slices. The BPF of the follow-up years also came closer to the initial BPF value measured in the first year. The statistical analysis of the BPF and R1, R2 and PD, showed a very low correlation (0.1) between BPF and PD, and intermediate correlations between BPF and R1, R2 (0.385 and -0.51, respectively). Future work will focus on understanding how these results relate to edema.

  • 244.
    Björneld, Olle
    Linköpings universitet, Institutionen för medicinsk teknik.
    Optisk instrument för Laparoskopisk Kärldetektion1996Independent thesis Advanced level (degree of Master (One Year)), 20 poäng / 30 hpOppgave
    Abstract [sv]

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

  • 245. Björnemo, M.
    et al.
    Brun, Anders
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för medicinsk teknik, Medicinsk informatik.
    Kikinis, R.
    Westin, C.-F.
    Regularized stochastic white matter tractography using diffusion tensor MRI2002Inngår i: Medical Image Computing and Computer-Assisted Intervention MICCAI02,2002, 2002Konferansepaper (Fagfellevurdert)
  • 246.
    Black, David
    et al.
    Medical Image Computing, University of Bremen; Jacobs University, Bremen; Fraunhofer MEVIS, Bremen, Germany.
    Hahn, Horst
    Jacobs University, Bremen; Fraunhofer, MEVIS, Germany.
    Kikinis, Ron
    Brigham and Women's Hospital and Harvard Medical School, Boston, USA.
    Wårdell, Karin
    Linköpings universitet, Institutionen för medicinsk teknik, Avdelningen för medicinsk teknik. Linköpings universitet, Tekniska fakulteten.
    Haj Hosseini, Neda
    Linköpings universitet, Institutionen för medicinsk teknik, Avdelningen för medicinsk teknik. Linköpings universitet, Tekniska fakulteten.
    Auditory display for Fluorescence-guided open brain tumor surgery2018Inngår i: International Journal of Computer Assisted Radiology and Surgery, ISSN 1861-6410, E-ISSN 1861-6429, Vol. 13, nr 1, s. 25-35Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    PURPOSE:

    Protoporphyrin (PpIX) fluorescence allows discrimination of tumor and normal brain tissue during neurosurgery. A handheld fluorescence (HHF) probe can be used for spectroscopic measurement of 5-ALA-induced PpIX to enable objective detection compared to visual evaluation of fluorescence. However, current technology requires that the surgeon either views the measured values on a screen or employs an assistant to verbally relay the values. An auditory feedback system was developed and evaluated for communicating measured fluorescence intensity values directly to the surgeon.

    METHODS:

    The auditory display was programmed to map the values measured by the HHF probe to the playback of tones that represented three fluorescence intensity ranges and one error signal. Ten persons with no previous knowledge of the application took part in a laboratory evaluation. After a brief training period, participants performed measurements on a tray of 96 wells of liquid fluorescence phantom and verbally stated the perceived measurement values for each well. The latency and accuracy of the participants' verbal responses were recorded. The long-term memorization of sound function was evaluated in a second set of 10 participants 2-3 and 7-12 days after training.

    RESULTS:

    The participants identified the played tone accurately for 98% of measurements after training. The median response time to verbally identify the played tones was 2 pulses. No correlation was found between the latency and accuracy of the responses, and no significant correlation with the musical proficiency of the participants was observed on the function responses. Responses for the memory test were 100% accurate.

    CONCLUSION:

    The employed auditory display was shown to be intuitive, easy to learn and remember, fast to recognize, and accurate in providing users with measurements of fluorescence intensity or error signal. The results of this work establish a basis for implementing and further evaluating auditory displays in clinical scenarios involving fluorescence guidance and other areas for which categorized auditory display could be useful.

  • 247.
    Blomstedt, Patric
    et al.
    Umeå University, Sweden .
    Fytagoridis, Anders
    Umeå University, Sweden .
    Åström, Mattias
    Linköpings universitet, Institutionen för medicinsk teknik, Biomedicinsk instrumentteknik. Linköpings universitet, Tekniska högskolan.
    Linder, Jan
    Umeå University, Sweden .
    Forsgren, Lars
    Umeå University, Sweden .
    Hariz, Marwan I.
    Umeå University, Sweden .
    Unilateral caudal zona incerta deep brain stimulation for Parkinsonian tremor2012Inngår i: Parkinsonism & Related Disorders, ISSN 1353-8020, E-ISSN 1873-5126, Vol. 18, nr 10, s. 1062-1066Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Background: The subthalamic nucleus is currently the target of choice in deep brain stimulation (DBS) for Parkinsons disease (PD), while thalamic DBS is used in some cases of tremor-dominant PD. Recently, a number of studies have presented promising results from DBS in the posterior subthalamic area, including the caudal zona incerta (cZi). The aim of the current study was to evaluate cZi DBS in tremor-dominant Parkinsons disease. less thanbrgreater than less thanbrgreater thanMethods: 14 patients with predominately unilateral tremor-dominant PD and insufficient relief from pharmacologic therapy were included and evaluated according to the motor part of the Unified Parkinson Disease Rating Scale (UPDRS). The mean age was 65 +/- 6.1 years and the disease duration 7 +/- 5.7 years. Thirteen patients were operated on with unilateral cZi DBS and 1 patient with a bilateral staged procedure. Five patients had non-L-dopa responsive symptoms. The patients were evaluated on/off medication before surgery and on/off medication and stimulation after a minimum of 12 months after surgery. less thanbrgreater than less thanbrgreater thanResults: At the follow-up after a mean of 18.1 months stimulation in the off-medication state improved the contralateral UPDRS III score by 47.7%. Contralateral tremor, rigidity, and bradykinesia were improved by 82.2%, 34.3%, and 26.7%, respectively. Stimulation alone abolished tremor at rest in 10 (66.7%) and action tremor in 8 (533%) of the patients. less thanbrgreater than less thanbrgreater thanConclusion: Unilateral cZi DBS seems to be safe and effective for patients with severe Parkinsonian tremor. The effects on rigidity and bradykinesia were, however, not as profound as in previous reports of DBS in this area.

  • 248. Bolger, A F
    et al.
    Eidenvall, L
    Ask, Per
    Linköpings universitet, Institutionen för medicinsk teknik, Fysiologisk mätteknik. Linköpings universitet, Tekniska högskolan.
    Loyd, Dan
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Mekanisk värmeteori och strömningslära. Linköpings universitet, Tekniska högskolan.
    Wranne, Bengt
    Linköpings universitet, Institutionen för medicin och vård, Klinisk fysiologi. Linköpings universitet, Hälsouniversitetet. Östergötlands Läns Landsting, Hjärt- och Medicincentrum, Fysiologiska kliniken US.
    Understanding continuous-wave Doppler signal intensity as a measure of regurgitant severity.1997Inngår i: Journal of the American Society of Echocardiography, ISSN 0894-7317, E-ISSN 1097-6795, Vol. 10, nr 6, s. 613-622Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Continuous-wave Doppler signal intensity is commonly expected to reflect the severity of mitral regurgitation. Physical principles predict that alignment of the imaging beam, flow velocity, and turbulence can also be important or even dominant determinants of continuous-wave Doppler signal intensity. The reliability of tracking regurgitant severity with continuous-wave Doppler signal intensity was assessed in vitro with varying volume, velocity, turbulence, and beam alignment. The conditions wherein continuous-wave Doppler signal intensity increased with regurgitant volume were specific but poorly predictable combinations of orifice size, flow volume, and perfect beam alignment. Under other conditions flow velocity and turbulence effects dominated, and continuous-wave Doppler signal intensity did not reflect changing regurgitant volume. Continuous-wave Doppler signal intensity-based impressions of regurgitant severity may be unreliable and even misleading under some circumstances.

  • 249. Bolger, Ann
    et al.
    Eidenvall, Lars
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för medicinsk teknik, Fysiologisk mätteknik.
    Ask, Per
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för medicinsk teknik, Fysiologisk mätteknik.
    Loyd, Dan
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för konstruktions- och produktionsteknik, Mekanisk värmeteori och strömningslära.
    Wranne, Bengt
    Linköpings universitet, Hälsouniversitetet. Linköpings universitet, Institutionen för medicin och vård, Klinisk fysiologi. Östergötlands Läns Landsting, Hjärtcentrum, Fysiologiska kliniken.
    Understanding continuous wave Doppler signal intensity as a measure of regurgitant severity1997Inngår i: Journal of the American Society of Echocardiography, ISSN 0894-7317, E-ISSN 1097-6795, Vol. 10, s. 613-622Artikkel i tidsskrift (Fagfellevurdert)
  • 250.
    Bolger, Ann F
    et al.
    Linköpings universitet, Institutionen för medicin och hälsa, Avdelningen för kardiovaskulär medicin. Linköpings universitet, Hälsouniversitetet. Östergötlands Läns Landsting, Hjärt- och Medicincentrum, Fysiologiska kliniken US.
    Eidenvall, Lars
    Ask, Per
    Linköpings universitet, Institutionen för medicinsk teknik, Fysiologisk mätteknik. Linköpings universitet, Tekniska högskolan.
    Loyd, Dan
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Mekanisk värmeteori och strömningslära. Linköpings universitet, Tekniska högskolan.
    Wranne, Bengt
    Linköpings universitet, Institutionen för medicin och vård, Klinisk fysiologi. Linköpings universitet, Hälsouniversitetet. Östergötlands Läns Landsting, Hjärt- och Medicincentrum, Fysiologiska kliniken US.
    THE MULTIPLE DETERMINANTS OF CONTINUOUS WAVE SIGNAL INTENSITY1992Inngår i: Circulation, ISSN 0009-7322, E-ISSN 1524-4539, Vol. 86, nr 4, SArtikkel i tidsskrift (Fagfellevurdert)
2345678 201 - 250 of 2206
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