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  • 1.
    Alanko, Rosanna
    et al.
    Högskolan i Jönköping, Hälsohögskolan, HHJ. Ortopedteknisk plattform.
    Oskarsson, Tina
    Högskolan i Jönköping, Hälsohögskolan, HHJ. Ortopedteknisk plattform.
    Kommunikation mellan patient och ortopedingenjör: En kvalitativ studie2016Självständigt arbete på grundnivå (kandidatexamen), 10 poäng / 15 hpStudentuppsats (Examensarbete)
    Abstract [sv]

    En studie har genomförts med syftet att undersöka diabetespatienters tolkning av informationen som ges av deras respektive ortopedingenjör under ett patientmöte samt undersöka vad ortopedingenjören anser sig ha förmedlat för information till patienten under patientmötet. Metoden i studien är kvalitativ där intervjuer med semistrukturerade öppna frågor har använts. I studien ingick två ortopedingenjörer samt två diabetespatienter. Efter avslutade intervjuer har materialet från intervjuerna analyserats och bildat kategorier. Dessa kategorier har sedan använts för att finna skillnader samt likheter mellan ortopedingenjörens och patientens tolkningar. Patientmötens har spelats in för att få möjligheten att se vart missförstånd uppstått. Genomgående i resultatet var att ortopedingenjören anser sig ha förmedlat mer information än vad patienten beskriver under intervjuerna. Några missförstånd upptäcktes men kommunikationen mellan parterna var god.  

  • 2. Bassan, Gioia
    et al.
    Larsson, David
    KTH, Medicinsk bildteknik.
    Nordenfur, Tim
    KTH, Medicinsk bildteknik.
    Bjällmark, Anna
    KTH, Medicinsk bildteknik.
    Larsson, Matilda
    KTH, Medicinsk bildteknik.
    Acquisition of multiple mode shear wave propagation in transversely isotropic medium using dualprobe setup2015Konferensbidrag (Refereegranskat)
  • 3. Beyene, Ayne A.
    et al.
    Welemariam, Tewelle
    Persson, Marie
    Blekinge Tekniska Högskola, Institutionen för datalogi och datorsystemteknik.
    Lavesson, Niklas
    Blekinge Tekniska Högskola, Institutionen för datalogi och datorsystemteknik.
    Improved concept drift handling in surgery prediction and other applications2015Ingår i: Knowledge and Information Systems, ISSN 0219-1377, E-ISSN 0219-3116, Vol. 44, nr 1, s. 177-196Artikel i tidskrift (Refereegranskat)
    Abstract [en]

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

  • 4.
    Bjällmark, Anna
    et al.
    KTH, Medicinsk teknik.
    Gustafsson, U
    Brodin, Lars-Åke
    KTH, Medicinsk teknik.
    Waldenström, A
    Larsson, Matilda
    KTH, Medicinsk teknik.
    A system to quantify and visualize ventricular rotation pattern of the heart2009Patent (Övrig (populärvetenskap, debatt, mm))
    Abstract [en]

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

  • 5.
    Bjällmark, Anna
    et al.
    Royal Institute of Technology, Stockholm, Sweden.
    Larsson, M
    Royal Institute of Technology, Stockholm, Sweden.
    Grishenkov, D
    Royal Institute of Technology, Stockholm, Sweden.
    Brodin, L-A
    Royal Institute of Technology, Stockholm, Sweden.
    Brismar, TB
    Karolinska University Hospital, Huddinge, Sweden.
    Paradossi, G
    Università di Roma Tor Vergata, Rome, Italy.
    Multifunctionalized microballoons for three modality contrast imaging: ultrasound, MRI and SPECT2012Konferensbidrag (Övrigt vetenskapligt)
  • 6.
    Bjällmark, Anna
    et al.
    KTH, Huddinge, Sweden.
    Larsson, M.
    KTH, Huddinge, Sweden.
    Lundback, S.
    Inovacor AB, Vaxholm, Sweden.
    Johnsson, J.
    GrippingHeart AB, Stockholm, Sweden.
    Winter, R.
    Karolinska University Hospital, Huddinge, Sweden.
    Brodin, L.-A.
    Karolinska University Hospital, Huddinge, Sweden.
    A new graphical user interface module generating state diagrams of the heart2006Ingår i: European Journal of Echocardiography, ISSN 1525-2167, E-ISSN 1532-2114, Vol. 7, nr suppl_1, s. S46-Artikel i tidskrift (Refereegranskat)
  • 7.
    Bjällmark, Anna
    et al.
    KTH Royal Institute of Technology, Sweden and Karolinska Institutet, Sweden.
    Larsson, Malin
    KTH Royal Institute of Technology, Sweden.
    Larsson, Matilda
    KTH Royal Institute of Technology, Sweden and Karolinska Institutet, Sweden.
    Grishenkov, Dmitry
    KTH Royal Institute of Technology, Sweden and Karolinska Institutet, Sweden.
    Paradossi, Gaio
    Università di Roma Tor Vergata, Italy.
    Poehlmann, Melanie
    University of Bayreuth, Germany.
    Dähne, Lars
    Surflay Nanotec GmbH, Germany.
    Gustafsson, Björn
    Karolinska Institutet, Sweden.
    Brismar, Torkel
    Karolinska Institutet, Sweden.
    Caidahl, Kenneth
    Karolinska Institutet, Sweden.
    Brodin, Lars-Åke
    KTH Royal Institute of Technology, Sweden.
    Three modality contrast imaging using multi-functionalized microbubbles: Achievements so far in the FP7-NMP project 3MiCRON (245575)2013Konferensbidrag (Övrigt vetenskapligt)
  • 8.
    Bjällmark, Anna
    et al.
    KTH, Medicinsk teknik.
    Larsson, Matilda
    KTH, Medicinsk teknik.
    Brodin, Lars-Åke
    KTH, Medicinsk teknik.
    Nowak, Jacek
    Lind, Britta
    KTH, Medicinsk teknik.
    Hayashi, Shirley
    Mazza do Nascimento, Marcelo
    Riella, Miquel
    Seeberger, Astrid
    Effects of hemodialysis on the cardiovascular system: Quantitative analysis using wave intensity wall analysis and tissue velocity imaging2010Ingår i: Heart and Vessels, ISSN 0910-8327, E-ISSN 1615-2573Artikel i tidskrift (Refereegranskat)
    Abstract [en]

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

  • 9.
    Bjällmark, Anna
    et al.
    KTH, Medicinsk teknik.
    Larsson, Matilda
    KTH, Medicinsk teknik.
    Shahgaldi, Kambiz
    Lind, Britta
    KTH, Skolan för teknik och hälsa (STH).
    Winter, Reidar
    Brodin, Lars-Ake
    KTH, Medicinsk teknik.
    Differences in myocardial velocities during supine and upright exercise stress echocardiography in healthy adults2009Ingår i: Clinical Physiology and Functional Imaging, ISSN 1475-0961, E-ISSN 1475-097X, Vol. 29, nr 3, s. 216-223Artikel i tidskrift (Refereegranskat)
    Abstract [en]

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

  • 10.
    Bjällmark, Anna
    et al.
    KTH, Medicinsk teknik.
    Lind, Britta
    KTH, Medicinsk teknik.
    Brodin, Lars-Åke
    KTH, Medicinsk teknik.
    Peolsson, Michael
    KTH, Skolan för teknik och hälsa (STH).
    Shahgaldi, Kambiz
    KTH, Medicinsk teknik.
    Nowak, Jacek
    Ultrasonographic strain imaging is superior to conventional non-invasive measures of vascular stiffness in the detection of age-dependent differences in the mechanical properties of the common carotid artery2010Ingår i: European Journal of Echocardiography, ISSN 1525-2167, E-ISSN 1532-2114, Vol. 11, nr 7, s. 630-636Artikel i tidskrift (Refereegranskat)
    Abstract [en]

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

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

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

  • 11.
    Brodin, Lars-Åke
    et al.
    KTH, Medicinsk teknik.
    Elmqvist, H
    Bjällmark, Anna
    KTH, Medicinsk teknik.
    Larsson, Matilda
    KTH, Medicinsk teknik.
    Global and local detection of blood vessel elasticity2006Patent (Övrig (populärvetenskap, debatt, mm))
    Abstract [en]

    The present invention is a non-invasive analysis system for detection of global and local blood vessel elasticity. The analysis system comprises two subsystems where subsystem 1 is data collecting unit and subsystem 2 is an analysis unit. The data collecting unit comprises one or many non-invasive image generating systems, or the data collecting system makes the registration possible of movement parameters that quantifies the dynamics of the blood vessel wall in longitudinal and radial directions. Subsystem 2 performs Wave Intensity Analysis which is an analysis method using co-related parts of the circulation system by measuring the intensity change (dl) of the blood vessel during a heart cycle. The intensity change is calculated as the product of the pressure derivate and the flow velocity derivate. In subsystem 2 the changes of pressure and flow are approximated by the deformation velocity or velocity of the radial and longitudinal direction, respectively. By calculating time constants and amplitudes of the intensity change graph a measure is obtained of the local and global elasticity of the blood vessel and atherosclerotic constrictions of arterial vessels may then be identified at an early stage.

  • 12.
    Broman, Adam
    et al.
    Högskolan i Jönköping, Hälsohögskolan, HHJ, Avd. för rehabilitering.
    Blom, Gustav
    Högskolan i Jönköping, Hälsohögskolan, HHJ, Avd. för rehabilitering.
    Assessment of function of a 3D-printed body-powered upper limb prosthetic device2019Självständigt arbete på grundnivå (kandidatexamen), 10 poäng / 15 hpStudentuppsats (Examensarbete)
    Abstract [en]

    Purpose

    Conventional arm-prosthesis are expensive to make and therefore limit the availability for users on the geographical locations there the user pays for it. This study compares the hand function of a 3D-printed prosthesis with lower production cost with a traditional prosthesis.

    Method

    A test person performed two different tests of hand function (Box and Block test and Nine-hole peg test) with a myoelectric trans radial prosthetic arm and a body powered 3D printed trans radial prosthetic arm. The test person also answered two parts of the orthotics and prosthetics users’ survey (OPUS) considering both prosthetic arms.

    Result

    The 3D-printed prosthesis performed worse than the traditional prosthesis in the two tests of hand function and generally worse in the questionnaire about the function of the prosthesis. Though it got higher values in comfort and affordability.

    Conclusion

    There was a significant difference in function between the 3D-printed prosthesis and the myoelectric prosthesis but the printed prosthesis could perform many activities in daily living. Whether the 3D-printed prosthetic device is priceworthy or not is hard to measure because of different criteria, therefore a conclusion is hard to reach.

  • 13.
    Broomé, Michael
    et al.
    KTH, Medicinsk bildteknik.
    Frenckner, Björn
    ECMO Department, Karolinska University Hospital, Stockholm.
    Broman, Mikaeö
    ECMO Department, Karolinska University Hospital, Stockholm.
    Bjällmark, Anna
    KTH, Medicinsk bildteknik.
    Recirculation during veno-venous extra-corporeal membrane oxygenation: A simulation study2015Ingår i: International Journal of Artificial Organs, ISSN 0391-3988, E-ISSN 1724-6040, Vol. 38, nr 1, s. 23-30Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    PURPOSE:

    Veno-venous ECMO is indicated in reversible life-threatening respiratory failure without life-threatening circulatory failure. Recirculation of oxygenated blood in the ECMO circuit decreases efficiency of patient oxygen delivery but is difficult to measure. We seek to identify and quantify some of the factors responsible for recirculation in a simulation model and compare with clinical data.

    METHODS:

    A closed-loop real-time simulation model of the cardiovascular system has been developed. ECMO is simulated with a fixed flow pump 0 to 5 l/min with various cannulation sites - 1) right atrium to inferior vena cava, 2) inferior vena cava to right atrium, and 3) superior+inferior vena cava to right atrium. Simulations are compared to data from a retrospective cohort of 11 consecutive adult veno-venous ECMO patients in our department.

    RESULTS:

    Recirculation increases with increasing ECMO-flow, decreases with increasing cardiac output, and is highly dependent on choice of cannulation sites. A more peripheral drainage site decreases recirculation substantially.

    CONCLUSIONS:

    Simulations suggest that recirculation is a significant clinical problem in veno-venous ECMO in agreement with clinical data. Due to the difficulties in measuring recirculation and interpretation of the venous oxygen saturation in the ECMO drainage blood, flow settings and cannula positioning should rather be optimized with help of arterial oxygenation parameters. Simulation may be useful in quantification and understanding of recirculation in VV-ECMO.

  • 14.
    Broomé, Michael
    et al.
    KTH, Medicinsk avbildning.
    Maksuti, Elira
    KTH, Medicinsk avbildning.
    Bjällmark, Anna
    KTH, Medicinsk avbildning.
    Frenckner, Björn
    Janerot-Sjöberg, Birgitta
    KTH, Medicinsk avbildning.
    Closed-loop real-time simulation model of hemodynamics and oxygen transport in the cardiovascular system2013Ingår i: Biomedical engineering online, ISSN 1475-925X, E-ISSN 1475-925X, Vol. 12, nr 1, s. 69-Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Background: Computer technology enables realistic simulation of cardiovascular physiology. The increasing number of clinical surgical and medical treatment options imposes a need for better understanding of patient-specific pathology and outcome prediction. Methods: A distributed lumped parameter real-time closed-loop model with 26 vascular segments, cardiac modelling with time-varying elastance functions and gradually opening and closing valves, the pericardium, intrathoracic pressure, the atrial and ventricular septum, various pathological states and including oxygen transport has been developed. Results: Model output is pressure, volume, flow and oxygen saturation from every cardiac and vascular compartment. The model produces relevant clinical output and validation of quantitative data in normal physiology and qualitative directions in simulation of pathological states show good agreement with published data. Conclusion: The results show that it is possible to build a clinically relevant real-time computer simulation model of the normal adult cardiovascular system. It is suggested that understanding qualitative interaction between physiological parameters in health and disease may be improved by using the model, although further model development and validation is needed for quantitative patient-specific outcome prediction.

  • 15.
    Chen, Janice D.
    et al.
    School of Occupational Therapy and Social Work, Curtin University, Perth 6845, Australia.
    Falkmer, Torbjörn
    Högskolan i Jönköping, Hälsohögskolan, HHJ. CHILD.
    Parsons, Richard
    School of Occupational Therapy and Social Work, Curtin University, Perth 6845, Australia.
    Buzzard, Jennifer
    Ramsey Health, Hollywood Hospital, Perth 6009, Australia.
    Ciccarelli, Marina
    School of Occupational Therapy and Social Work, Curtin University, Perth 6845, Australia.
    Impact of experience when using the Rapid Upper Limb Assessment to assess postural risk in children using information and communication technologies2014Ingår i: Applied Ergonomics, ISSN 0003-6870, E-ISSN 1872-9126, Vol. 45, nr 3, s. 398-405Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The Rapid Upper Limb Assessment (RULA) is an observation-based screening tool that has been used to assess postural risks of children in school settings. Studies using eye-tracking technology suggest that visual search strategies are influenced by experience in the task performed. This study investigated if experience in postural risk assessments contributed to differences in outcome scores on the RULA and the visual search strategies utilized. While wearing an eye-tracker, 16 student occupational therapists and 16 experienced occupational therapists used the RULA to assess 11 video scenarios of a child using different mobile information and communication technologies (ICT) in the home environment. No significant differences in RULA outcome scores, and no conclusive differences in visual search strategies between groups were found. RULA can be used as a screening tool for postural risks following a short training session regardless of the assessor's experience in postural risk assessments. (C) 2013 Elsevier Ltd and The Ergonomics Society. All rights reserved.

  • 16.
    Dranvik, Madeleine
    et al.
    Högskolan i Jönköping, Hälsohögskolan, HHJ. Ortopedteknisk plattform.
    Nyholm, Hanna
    Högskolan i Jönköping, Hälsohögskolan, HHJ. Ortopedteknisk plattform.
    Jämförelse av två ankelortosers inversionsrestriktion före och efter fysisk aktivitet2017Självständigt arbete på grundnivå (kandidatexamen), 10 poäng / 15 hpStudentuppsats (Examensarbete)
  • 17.
    Eklund, Jörgen
    et al.
    KTH, Ergonomi.
    Engkvist, Inga-Lill
    KTH, Ergonomi.
    Karltun, Johan
    Högskolan i Jönköping, Tekniska Högskolan, JTH. Forskningsmiljö Industriell produktion.
    Vogel, Kjerstin
    KTH, Ergonomi (Stängd 20130701).
    Styckarnas arbetssituation: Ett interaktivt forskningprogram för branschstöd och utveckling av åtgärder (Star). dnr 0800142012Rapport (Övrigt vetenskapligt)
  • 18.
    Fagerlind, Anna
    Högskolan i Jönköping, Tekniska Högskolan, JTH, Maskinteknik.
    Spruttransporten2010Självständigt arbete på grundnivå (yrkesexamen), 10 poäng / 15 hpStudentuppsats (Examensarbete)
  • 19. Falkmer, Torbjörn
    et al.
    Bjällmark, Anna
    Larsson, M.
    Falkmer, Marita
    Face Processing in Persons with Asperger Syndrome2011Konferensbidrag (Övrigt vetenskapligt)
  • 20. Falkmer, Torbjörn
    et al.
    Bjällmark, Anna
    Larsson, M.
    Falkmer, Marita
    Recognition of Faces and Expressions for People with Asperger Syndrome: The Nature of the Problem2006Konferensbidrag (Övrigt vetenskapligt)
  • 21.
    Filipsson, Emma
    et al.
    Högskolan i Jönköping, Hälsohögskolan, HHJ, Avd. för naturvetenskap och biomedicin.
    Olsson, Cecilia
    Högskolan i Jönköping, Hälsohögskolan, HHJ, Avd. för naturvetenskap och biomedicin.
    Interobserver variability when measuring the abdominal aorta with ultrasound: A comparison using the longitudinal and transverse axes2018Självständigt arbete på grundnivå (kandidatexamen), 10 poäng / 15 hpStudentuppsats (Examensarbete)
    Abstract [sv]

     

    Ett rupturerande bukaortaaneurysm har en dödlighet på 50% medan förebyggande vaskulär kirurgi har en dödlighet på 3-8%. Screeingprogram med ultraljud används i vissa länder för att upptäcka bukaortaaneurysm i ett tidigt skede innan de rupterar. Ultraljudsundersökningen är dock väldigt beroende på utövarens erfarenhet och utbildning. Studien genomfördes i Vietnam, ett land som genomgått stor ekonomisk tillväxt men även en ökning av riskfaktorer för kardiovaskulära sjukdomar. Vietnam har dock inget nationellt screeningprogram för bukaortaaneurysm. Syftet med studien var att undersöka observatörsvariationen vid mätning av bukaortan med ultraljud på unga vuxna i Vietnam. Populationen var ung för att minska patologiska fynd. Bukaortan mättes med metoden leading edge to leading edge, både i det longitudinella och i det transversella snittet av två olika utövare. Observatörerna var två studenter från Biomedicinska analytikerprogrammet med inriktning klinisk fysiologi, Jönköpings Universitet. Deltagare i studien var 31 frivilliga studenter, 16 män och 15 kvinnor i åldrarna 18-26 år, från Da Nang University of medical technology and pharmacy och designen var en tvärsnittsstudie med kvantitativ ansats. Studien visade en signifikant skillnad i de longitudinella mätningarna men inte i de transversella mätningarna. Trots denna statistiska signifikans var observatörernas differenser inom den rekommenderade gränsen på 5 mm.

  • 22.
    Gustafsson, U
    et al.
    Umeå University Hospital, Umeå, Sweden.
    Larsson, M.
    Royal Institute of Technology, Stockholm, Sweden.
    Bjällmark, Anna
    Royal Institute of Technology, Stockholm, Sweden.
    Lindqvist, P.
    Umeå University Hospital, Umeå, Sweden.
    A'roch, R.
    Umeå University Hospital, Umeå, Sweden.
    Haney, M.
    Umeå University Hospital, Umeå, Sweden.
    Waldenstrom, A.
    Umeå University Hospital, Umeå, Sweden.
    The rotation axis of the left ventricle in acute myocardial ischemia2010Ingår i: European Journal of Echocardiography, ISSN 1525-2167, E-ISSN 1532-2114, Vol. 11, nr suppl_2, s. ii124-ii154, artikel-id P908Artikel i tidskrift (Refereegranskat)
  • 23.
    Gustafsson, U
    et al.
    Umeå University Hospital, Umeå, Sweden.
    Larsson, M.
    Royal Institute of Technology, Stockholm, Sweden.
    Bjällmark, Anna
    Royal Institute of Technology, Stockholm, Sweden.
    Lindqvist, P.
    Umeå University Hospital, Umeå, Sweden.
    Brodin, L.
    Royal Institute of Technology, Stockholm, Sweden.
    Waldenstrom, A.
    Umeå University Hospital, Umeå, Sweden.
    The rotation axis of the left ventricle. A new concept in cardiac function2010Ingår i: European Journal of Echocardiography, ISSN 1525-2167, E-ISSN 1532-2114, Vol. 11, nr suppl_2, s. ii45-ii75, artikel-id P499Artikel i tidskrift (Refereegranskat)
  • 24. Hayashi, S Y
    et al.
    Nascimento, MM
    Lindholm, B
    Lind, B
    Seeberger, A
    Nowak, J
    Pachaly, M. Aparecida
    Riella, M
    Bjällmark, Anna
    Brodin, L-Å
    Left ventricular mechanical dyssynchrony in CKD stages 3-4 and dialysis patients.2010Konferensbidrag (Övrigt vetenskapligt)
  • 25.
    Hägg, Göran M
    et al.
    KTH, Ergonomi.
    Vogel, Kjerstin
    KTH, Ergonomi.
    Karltun, Johan
    Högskolan i Jönköping, Tekniska Högskolan, JTH. Forskningsmiljö Industriell produktion.
    McGorry, Raymond
    Knife force differences when cutting meat at different temperatures2012Ingår i: NES2012: Ergonomics for Sustainability and Growth / [ed] Ann-Beth Antonsson, Kjerstin Vogel, Göran M Hägg, Stockholm: KTH Royal Institute of Technology, 2012Konferensbidrag (Refereegranskat)
    Abstract [en]

    Introduction

    Meat cutters in abattoirs is a group with high risks for musculoskeletal disorders. A major reason for this is that they exert high hand forces over a great part of the day when cutting meat. Though meat is refrigerated due to hygienic demands, meat temperature can vary. Meat cutters have claimed that knife forces increase with lower temperatures. This study was performed to find out what effects the meat temperature has on cutting forces. In addition, the same issue was addressed for pure fat.

    Method

    To be able to do cuts in meat under controlled conditions while measuring cutting forces, a machine, Anago KST Sharpness Analyzer, was used. The machine normally runs a knife at constant speed through a standardized textile ribbon while the force exerted on the ribbon is recorded over time. For this investigation, the ribbon was replaced by a wooden fixture with a 10 mm wide slot where the knife could pass and where meat samples could be fixed.Meat obtained from hind loin and fat tissue of pork was cut into 5 cm long, 4 cm wide and 2 cm thick samples. The meat fibre orientation was aligned with the long axis of the sample. When fixated in the fixture and the machine was started, the knife made a 4 cm long cut through 2 cm thick meat or fat.One hundred and forty four samples of meat and as many of fat were collected and put overnight in one of three refrigerators with temperatures 2, 7 and 12 °C, 48 in each. Well sharpened standard knifes were used for the tests. The knife was changed after 24 cuts. During the procedure samples were taken directly from the refrigerator and put into the fixture and tested immediately. The sample order was generally 2, 7, 12 °C to avoid systematic effects of a gradually blunter knife.

    Results

    There were no significant differences in knife forces at the three meat temperatures. The forces for fat were in average about three times higher than the meat forces. There was no significant difference between forces in fat at 7 and 12 °C. However there was a strongly significant difference between these two groups and the 2 °C fat group. The force was about 30% higher compared to the forces at 7 and 12 °C in fat.

    Conclusion

    In the range 2-12 °C there are no differences in meat. For fat there are no differences in the range 7-12 °C while the force increases about 30% when going from 7 to 2 °C.

  • 26.
    Härmark, Johan
    et al.
    KTH, Strukturell bioteknik.
    Larsson, Malin K.
    KTH, Medicinsk bildteknik.
    Razuvajev, Anton
    Koeck, Philip JB
    KTH, Strukturell bioteknik.
    Paradossi, Gaio
    Brodin, Lars-Åke
    KTH, Medicinsk bildteknik.
    Caidahl, Kenneth
    Hebert, Hans
    KTH, Strukturell bioteknik.
    Bjällmark, Anna
    KTH, Medicinsk bildteknik.
    Investigation of the elimination process of a multimodal polymer-shelled contrast agent in rats using ultrasound and transmission electron microscopy2015Ingår i: Biomedical Spectroscopy and Imaging, ISSN 2212-8794, Vol. 4, nr 1, s. 81-93Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    BACKGROUND: A novel polymer-shelled contrast agent (CA) with multimodal imaging and target specific potential was developed recently and tested for its acoustical properties using different in-vitro setups.

    OBJECTIVE: The aim of this study was to investigate the elimination of three types of the novel polymer-shelled CA, one unmodified and two shell modified versions, in rats.

    METHODS: The blood elimination time was estimated by measuring the image intensity, from ultrasound images of the common carotid artery, over time after a bolus injection of the three types of the novel CA. The commercially available CA SonoVue was used as a reference. The subcellular localization of the three CAs was investigated using transmission electron microscopy.

    RESULTS: The ultrasound measurements indicated a blood half-life of 17–85 s for the different types of the novel CA, which was significant longer than the blood half-life time for SonoVue. Additionally, CAs were exclusively found in the circulatory system, either taken up by, or found in the vicinity of macrophages.

    CONCLUSIONS: Compared to the commercially available CA SonoVue, the blood circulation times for the three types of the novel polymer-shelled CA were prolonged. Moreover, macrophages were suggested to be responsible for the elimination of the CA.

  • 27.
    Johansson, Frida
    et al.
    Högskolan i Jönköping, Tekniska Högskolan, JTH, Produktutveckling.
    Klarin, Johanna
    Högskolan i Jönköping, Tekniska Högskolan, JTH, Produktutveckling.
    Mechanical properties of trabecular structures produced by SLM, as a function of the trabecular morphology2017Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    Eurocoating, Italy, is a company that works in the biomedical sector. They have for a long time created prostheses from CAD files achieved from customers, and now they want to build their own expertise about the design. The thesis work was a part of a three year long collaborative research project between Eurocoating and University of Trento that was aiming to investigate the prostheses with open-porous surface and trabecular structure, created by Selective Laser Melting.

    The purpose of the thesis was to investigate and characterize 30 different trabecular structures of Ti-6Al-4V, fabricated by Selective Laser Melting. That includes investigation the effect on the morphology and porosity fraction caused by the manufacturing and the effect on mechanical and physical properties due to the different characterizations of the structures.

    The thesis work had its foundation in literature studies to receive deep knowledge about the subject. Practical tests were performed to investigate mechanical behaviour under compressive and tensile loading, static friction and wear resistance. The findings from these tests were compared to the porosity fraction and the morphological characterizations.

    The result stated that the porosity fraction was lower than the designed porosity, and that is was strongly influenced by size of the voids and struts. The strut thickness was higher than the design values, especially on the lateral surface, while the voids size were approximately as designed. Result from the compression test showed a trend of decreasing stiffness and strength with increasing porosity fraction. Also structures with same porosity fraction could have a wide range in mechanical properties which indicates high dependence on the morphological geometry i.e. pore size and shape, strut size and pore distribution. Comparisons between tensile and compression behaviour stated that the structures had a lower strength but a significant higher stiffness in tensile load. All structures from the wear test showed a good resistance while the results from the friction test needs further investigation to be fully understood.

    The physical and mechanical properties of the trabecular structures was found to be close to those of cortical and trabecular bone in porosity, stiffness and strength. There is a range of variations leading to possibilities to adopt the application depending on customer. Thus, these can be considered as promising structures used biomedical application to optimize osseointegration and secondary long term fixation.

  • 28.
    Larsson, Josefine
    et al.
    Högskolan i Jönköping, Hälsohögskolan, HHJ, Avd. för naturvetenskap och biomedicin.
    Karlsson, Caroline
    Högskolan i Jönköping, Hälsohögskolan, HHJ, Avd. för naturvetenskap och biomedicin.
    Patientens upplevelse av koldioxid efter en kolografiundersökning med datortomograf: En enkätstudie2015Självständigt arbete på grundnivå (kandidatexamen), 10 poäng / 15 hpStudentuppsats (Examensarbete)
  • 29. Larsson, M
    et al.
    Bjällmark, Anna
    Lind, B
    Balzano, R
    Peolsson, M
    Winter, R
    Brodin, L-Å
    Wave Intensity Wall Analysis: A novel noninvasive method for early detection of cardiovascular disease2007Konferensbidrag (Övrigt vetenskapligt)
  • 30.
    Larsson, M
    et al.
    Royal Institute of Technology, Stockholm, Sweden.
    Bjällmark, Anna
    Royal Institute of Technology, Stockholm, Sweden.
    Winter, R
    Karolinska University Hospital, Stockholm, Sweden.
    Westholm, C
    Karolinska University Hospital, Stockholm, Sweden.
    Jacobsen, P
    Karolinska University Hospital, Stockholm, Sweden.
    Lind, B
    Karolinska University Hospital, Stockholm, Sweden.
    Brodin, L-Å
    Royal Institute of Technology, Stockholm, Sweden.
    Velocity tracking: A novel method for quantitative analysis of longitudinal myocardial function2006Ingår i: Journal of Biomechanics, ISSN 0021-9290, E-ISSN 1873-2380, Vol. 39, nr Supplement 1, s. S1-S684, artikel-id S406Artikel i tidskrift (Refereegranskat)
  • 31. Larsson, M
    et al.
    Härmark, J.
    Razuvajev, A
    Caidahl, K
    Bjällmark, Anna
    Bioclearance of a novel polymer-shelled multimodal contrast agent2013Konferensbidrag (Övrigt vetenskapligt)
  • 32.
    Larsson, M.
    et al.
    Royal Institute of Technology, Stockholm, Sweden.
    Kremer, F
    Catholic University of Leuven, Leuven, Belgium.
    Kouznetsova, T
    Catholic University of Leuven, Leuven, Belgium.
    Bjällmark, Anna
    Royal Institute of Technology, Stockholm, Sweden.
    Lind, B
    Royal Institute of Technology, Stockholm, Sweden.
    Brodin, L.
    Royal Institute of Technology, Stockholm, Sweden.
    D'hooge, J
    Royal Institute of Technology, Stockholm, Sweden.
    Radial and longitudinal strain assessment in the carotid artery wall using speckle tracking2010Ingår i: European Journal of Echocardiography, ISSN 1525-2167, E-ISSN 1532-2114, Vol. 11, nr suppl_2, s. ii12-ii41, artikel-id P364Artikel i tidskrift (Refereegranskat)
  • 33. Larsson, M
    et al.
    Kremer, F
    Kuznetsova, T
    Lind, B
    Bjällmark, Anna
    Brodin, L-Å
    D'hooge, J
    3D Strain Imaging of the Arterial wall: An experimental validation study of an Ultrasound-based Speckle Tracking algorithm2011Konferensbidrag (Övrigt vetenskapligt)
  • 34. Larsson, M
    et al.
    Kremer, F
    Kuznetsova, T
    Lind, B
    Bjällmark, Anna
    Brodin, L-Å
    D'hooge, J
    Ultrasound-based 2D Strain Estimation of the Carotid Artery: an in-silico feasibility study2010Konferensbidrag (Övrigt vetenskapligt)
  • 35.
    Larsson, M
    et al.
    Royal Institute of Technology, Stockholm, Sweden.
    Larsson, M
    Royal Institute of Technology, Stockholm, Sweden.
    Bjällmark, Anna
    Royal Institute of Technology, Stockholm, Sweden.
    Winter, R
    Karolinska University Hospital, Huddinge, Sweden.
    Caidah, K
    Karolinska University Hospital, Stockholm, Sweden.
    Brodin, L-A
    Royal Institute of Technology, Stockholm, Sweden.
    A novel technique to visualize target specific polymeric contrast agents2011Ingår i: European Journal of Echocardiography, ISSN 1525-2167, E-ISSN 1532-2114, Vol. 12, nr suppl_2, s. ii90-ii120, artikel-id P725Artikel i tidskrift (Refereegranskat)
  • 36.
    Larsson, Malin
    et al.
    KTH, Medicinsk teknik.
    Bjällmark, Anna
    KTH, Medicinsk teknik.
    Larsson, Matilda
    KTH, Medicinsk teknik.
    Caidahl, Kenneth
    Karolinska Institutet.
    Winter, Reidar
    KTH, Medicinsk teknik.
    Brodin, Lars-Åke
    KTH, Medicinska sensorer, signaler och system (MSSS) (Stängd 20130701).
    A new ultrasound-based approach to visualize target specific polymeric contrast agent2011Ingår i: 2011 IEEE International Ultrasonics Symposium (IUS), IEEE , 2011, s. 1626-1629Konferensbidrag (Refereegranskat)
    Abstract [en]

    There are advantages of using a polymeric shelled contrast agent (CA) during ultrasound imaging instead of lipid shelled CA, e.g. particles can be attached to the surface, which enables an introduction of antibodies to the surface making the CA target specific. For this application it is essential to have a sensitive imaging technique suitable for polymeric CA. However, previously presented results have indicated difficulties in visualizing polymeric CA with commercially available contrast algorithms. Therefore a new subtraction algorithm (SA), was developed that define the difference between contrast and reference images. The aim of this study was to evaluate the response from a polymeric CA, when using the SA and compare it with existing contrast algorithms. Moreover, the possibility to detect a thin layer of CA was tested using the SA.

    Ultrasound short-axis images of a tissue-mimicking vessel phantom with a pulsating flow were obtained using a GE Vivid7 system (M12L) and a Philips iE33 system (S5-1). Repeated (n=91) contrast to tissue ratios (CTR) calculated at various mechanical index (MI) using the contrast algorithms pulse inversion (PI), power modulation (PM) and SA at a concentration of 105microbubbles/ml.

    The developed SA showed improvements in CTR compared to existing contrast algorithms. The CTRs were -0.99 dB ± 0.67 (MI 0.2), 9.46 dB ± 0.77 (MI 0.4) and 2.98 dB ± 0.60 (MI 0.8) with PI, 8.17 dB ± 1.15 (MI 0.2), 15.60 dB ± 1.29 (MI0.4) and 11.60 dB ± 0.73 (MI 0.8) with PM and 14.97 dB ± 3.97 (MI 0.2), 20.89 dB ± 3.54 (MI 0.4) and 21.93 dB ± 4.37 (MI 0.8) with the SA. In addition to this, the layer detection, when using the SA was successful.

  • 37.
    Larsson, Malin K.
    et al.
    KTH Royal Institute of Technology, Stockholm, Sweden.
    Larsson, Matilda
    KTH Royal Institute of Technology, Stockholm, Sweden and Karolinska Institutet, Solna, Sweden.
    Nowak, Greg
    Karolinska Institutet, Stockholm, Sweden.
    Paradossi, Gaio
    Università di Roma Tor Vergata, Rome, Italy.
    Brodin, Lars-Åke
    KTH Royal Institute of Technology, Stockholm, Sweden and Karolinska Institutet, Solna, Sweden.
    Janerot Sjöberg, Birgitta
    KTH Royal Institute of Technology, Stockholm, Sweden and Karolinska Institutet, Solna, Sweden.
    Caidahl, Kenneth
    Karolinska Institutet, Solna, Sweden.
    Bjällmark, Anna
    Endocardial border delineation capability of a multimodal polymer-shelled contrast agent2014Konferensbidrag (Övrigt vetenskapligt)
    Abstract [en]

    Background

    A novel polymer-shelled contrast agent (CA) with high mechanical and chemical stability was recently developed [1]. In excess to its ultrasound properties, it also supports targeted and multimodal imaging [2-4]. Even though these new possibilities have the potential to lead to new methodologies and approaches for non-invasive diagnosis, it is important that the fundamental diagnostic features in contrast-enhanced ultrasound are preserved. The aim of this study was therefore to examine the clinical use of the polymer-shelled CA by analyzing the left ventricular endocardial border delineation capability in a porcine model. In addition, physiological effects due to CA injections were studied.

    Methods

    The endocardial border delineation capability was assessed in a comparative study, which included three doses (1.5 ml, 3 ml and 5 ml, [5x108 MBs/ml]) of the polymer-shelled CA and the commercially available CA SonoVue® (1.5 ml, [2-5x108 MBs/ml]). Ultrasound images of the left ventricle were evaluated manually by blinded observers (n=3) according to a 6-segment model, in which each segment was graded as 0=not visible, 1=barely visible or 2=well visible, as well as semi-automatically by a segmentation software. Furthermore, duration of clinically useful contrast enhancement and changes in physiological parameters were evaluated.

    Results

    For the highest dose of the polymer-shelled CA, the obtained segment scores, time for clinically sufficient contrast enhancement and semi-automatic delineation capability were comparable to SonoVue®. Moreover, neither dose of the polymer-shelled CA did affect the physiological parameters.

    Conclusion

    This study demonstrated that the polymer-shelled CA can be used in contrast-enhanced diagnostic imaging without influence on major physiological parameters.

  • 38.
    Larsson, Matilda
    et al.
    School for Technology and Health, Royal Institute of Technology, Sweden.
    Bjällmark, Anna
    School for Technology and Health, Royal Institute of Technology, Sweden.
    Johnson, Jens
    School for Technology and Health, Royal Institute of Technology, Sweden.
    Winter, Reidar
    Department of Clinical Physiology, Karolinska University Hospital, Sweden.
    Brodin, Lars-Åke
    School for Technology and Health, Royal Institute of Technology, Sweden.
    Lundbäck, Stig
    Gripping Heart AB, KTH Business Lab, Sweden.
    State diagrams of the heart – a new approach to describing cardiac mechanics2009Ingår i: Cardiovascular Ultrasound, ISSN 1476-7120, E-ISSN 1476-7120, Vol. 7, nr 22Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Background: Cardiac time intervals have been described as a measure of cardiac performance, where prolongation, shortening and delay of the different time intervals have been evaluated as markers of cardiac dysfunction. A relatively recently developed method with improved ability to measure cardiac events is Tissue Doppler Imaging (TDI), allowing accurate measurement of myocardial movements.

    Methods: We propose the state diagram of the heart as a new visualization tool for cardiac time intervals, presenting comparative, normalized data of systolic and diastolic performance, providing a more complete overview of cardiac function. This study aimed to test the feasibility of the state diagram method by presenting examples demonstrating its potential use in the clinical setting and by performing a clinical study, which included a comparison of the state diagram method with established echocardiography methods (E/E' ratio, LVEF and WMSI). The population in the clinical study consisted of seven patients with non ST-elevation myocardial infarction (NSTEMI) and seven control subjects, individually matched according to age and gender. The state diagram of the heart was generated from TDI curves from seven positions in the myocardium, visualizing the inter- and intraventricular function of the heart by displaying the cardiac phases.

    Results: The clinical examples demonstrated that the state diagram allows for an intuitive visualization of pathological patterns as ischemia and dyssynchrony. Further, significant differences in percentage duration between the control group and the NSTEMI group were found in eight of the totally twenty phases (10 phases for each ventricle), e.g. in the transition phases (Pre-Ejection and Post-Ejection). These phases were significantly longer (> 2.18%) for the NSTEMI group than for the control group (p < 0.05). No significant differences between the groups were found for the established echocardiography methods.

    Conclusion: The test results clearly indicate that the state diagram has potential to be an efficient tool for visualization of cardiac dysfunction and for detection of NSTEMI.

  • 39.
    Larsson, Matilda
    et al.
    KTH, Medicinsk teknik.
    Kremer, F.
    Kuznetsova, T.
    Lind, Britta
    KTH, Medicinsk teknik.
    Bjällmark, Anna
    KTH, Medicinsk teknik.
    Brodin, Lars-Åke
    KTH, Medicinsk teknik.
    D'hooge, J.
    In-vivo assessment of radial and longitudinal strain in the carotid artery using speckle tracking2010Ingår i: 2010 IEEE International Ultrasonics Symposium Proceedings, IEEE , 2010, s. 1328-1331Konferensbidrag (Refereegranskat)
    Abstract [en]

    Ultrasound-based algorithms are commonly used to assess mechanical properties of arterial walls in studies of arterial stiffness and atherosclerosis. Speckle tracking based techniques used for estimation of myocardial strain can be applied on vessels to estimate strain of the arterial wall. Previous elastography studies in vessels have mainly focused on radial strain measurements, whereas the longitudinal strain has been more or less ignored. However, recently we showed the feasibility of speckle tracking to assess longitudinal strain of the carotid artery in-silico. The aim of this study was to test this methodology in-vivo. Ultrasound images were obtained in seven healthy subjects with no known cardiovascular disease (39 ± 14 years old) and in seven patients with coronary artery disease (CAD), (69 ± 4 years old). Speckle tracking was performed on the envelope detected data using our previous developed algorithm. Radial and longitudinal strains were estimated throughout two cardiac cycles in a region of interest (ROI) positioned in the posterior vessel wall. The mean peak systolic radial and longitudinal strain values from the two heart cycles were compared between the groups using a student's t-test. The mean peak radial strain was -39.1 ± 15.1% for the healthy group and -20.4 ± 7.5% for the diseased group (p = 0.01), whereas the mean peak longitudinal strain was 4.8 ± 1.1% and 3.2 ± 1.6% (p = 0.05) for the healthy and diseased group, respectively. Both peak radial and longitudinal strain values were thus significantly reduced in the CAD patient group. This study shows the feasibility to estimate radial and longitudinal strain in-vivo using speckle tracking and indicates that the method can detect differences between groups of healthy and diseased (CAD) subjects.

  • 40.
    Ma, Christina Zong-Hao
    et al.
    Department of Mechanical Engineering, University of Michigan; Department of Biomedical Engineering, The Hong Kong Polytechnic University.
    Bao, Tian
    Department of Mechanical Engineering, University of Michigan.
    Le, Victor C.
    Department of Mechanical Engineering, University of Michigan.
    Chambers, April
    Department of Bioengineering, University of Pittsburgh.
    Cham, Rakie
    Department of Bioengineering, University of Pittsburgh, Pittsburgh, USA.
    Shull, Peter
    Department of Mechanical Engineering, Shanghai Jiao Tong University.
    Zheng, Yong-Ping
    Department of Biomedical Engineering, The Hong Kong Polytechnic University.
    Sienko, Kathleen H.
    Department of Mechanical Engineering, University of Michigan.
    A feasibility study for gait training with foot-floor contact angle feedback2019Konferensbidrag (Refereegranskat)
    Abstract [en]

    Background and Aim: Slip events are responsible for up to 20% of falls and often result in severe injuries, and significant mortality and morbidity. Prior research has revealed several factors that increase the likelihood of a slip event including walking with a large foot-floor contact angle (FFCA) at heel-strike (>20°). Numerous feedback systems leveraging wearable sensors that measure gait-related kinematic or kinetic data have been used to improve balance and gait performance. In this feasibility study we demonstrated the use of a wearable feedback device for modifying FFCA during treadmill walking.

    Methods: Ten healthy participants (3 females and 7 males, aged 22.0±1.6 years) with fewer than 75% of baseline overground FFCA values falling within a range of 10-20° were recruited for inclusion in the study. A feedback system comprising two IMUs attached to the mid-foot regions of participants' dominant and non-dominant feet to measure FFCA during heel strike events, a laptop for calculating FFCA, and speakers for providing auditory cues to participants was used. Participants received cues during the non-dominant foot stance phase if the average of the two preceding dominant FFCAs was outside of the target range (10-20°). Participants performed 2-min baseline and post-training treadmill trials with a speed of 1.35 m/s prior to and following four 4-min treadmill training trials with FFCA feedback. The percentage of FFCAs within the target range, and the mean and variability of FFCAs were computed for baseline, training, and post-training trials, and one-way repeated measures ANOVA and post-hoc comparisons were performed. The significance level was 0.05.

    Results: Participants increased their percentage of FFCAs within the target range when feedback was provided during the training trials compared to the no feedback condition during the baseline trials (66.9% vs. 53.9%, P=0.028). Increased percentages of FFCAs within the target range were also observed during the post-training trials (75.8% vs. 53.9%, P=0.027). The average FFCA increased from 9.9° during baseline trials to 13.7° during training trials (P=0.028). The FFCAs were less variable during the training (P=0.028) and post-training (P=0.028) trials compared to the baseline trials.

    Conclusions: The findings suggest that participants could use the auditory cues to dynamically adjust their FFCAs while walking on a treadmill and that the training effects were present for a short period of time following the completion of the training. The FFCA is one of several gait parameters that could be used for gait training purposes to potentially reduce the likelihood of a slip event. Future work should examine the effects of gait training with FFCA feedback on the incidence and severity of slips, and on other gait parameters.

  • 41.
    Ma, Christina Zong-Hao
    et al.
    Högskolan i Jönköping, Hälsohögskolan, HHJ, Avd. för rehabilitering. Department of Mechanical Engineering, University of Michigan; Department of Biomedical Engineering, The Hong Kong Polytechnic University.
    Chung, Alan Kai-Lun
    Department of Biomedical Engineering, The Hong Kong Polytechnic University, Hong Kong.
    Ling, Yan To
    Department of Biomedical Engineering, The Hong Kong Polytechnic University, Hong Kong.
    Huang, Zihao
    ngineering, The Hong Kong Polytechnic University, Hong Kong.
    Cheng, Connie Lok-Kan
    Department of Biomedical Engineering, The Hong Kong Polytechnic University, Hong Kong.
    Zheng, Yong-Ping
    Department of Biomedical Engineering, The Hong Kong Polytechnic University.
    Smart Insole and Smartwatch System with Big Data Analytics to Improve Balance Training and Walking Ability2019Konferensbidrag (Refereegranskat)
    Abstract [en]

    BACKGROUND 

    Applying wearable motion sensors to capture balance/gait performance and provide the corresponding biofeedback/reminder have been proved effective in improving users’ balance/gait [1-5]. Unfortunately, previous approach of providing pre-set biofeedback did not consider user’s individual balance performance or training process during various tasks. Big data analytics and machine learning technologies have been widely used to monitor the daily physical activity [6-8]. However, few previous studies have utilized these technologies to improve balance/gait training.

    AIM

    This study aimed to develop a foot-motion based smart insole and smartwatch system integrated with big data analytics, and investigate its effect on improvement of balance training in patients with stroke.

    METHOD 

    The newly-developed system with big data analytics can collect and store patients’ balance performance and their response to the reminder/biofeedback during each session of balance/gait training. With the collected huge amount of data (big data) of patients’ balance and response to the biofeedback, the system can identify and extract the feature of patients’ response upon receiving the biofeedback, and further deliver the customized biofeedback (that gradually changed according to the balance improvement) for patients to further improve balance and gait training outcomes (machine learning).

    A randomized controlled trial will be conducted on 12 patients with stroke by evaluating patient’s balance/gait training outcomes with and without using the developed system.

    RESULTS

    The development of hardware of the system were completed, and the development of software were in progress. The system contained: 1) personal unit with force and motion sensors placed at both feet to capture the foot motion, and a smartwatch at wrist to collect data from both feet via Bluetooth and then transmit the data to the central cloud server via WiFi; 2) central cloud servers for data transmission and storage; 3) user interface for data analysis, which included a smartphone, tablet, and/or laptop; and 4) workstation for big data analytics (Figure 1). The collected data involved all sensor signals the system received before and after delivering biofeedback, and from day to day monitoring of patients. The customized biofeedback pattern included various type, frequency, magnitude, and amount/dosage of biofeedback.

    DISCUSSION AND CONCLUSION 

    The introduced system adopted big data and machine learning technologies to provide the repetitive targeted balance and gait training based on each patient’s condition. With further optimization, this system can also be applied in elderly and other patients with balance disorders for various daily tasks, including standing, walking, and obstacle crossing. This will enhance the balance training outcomes and potentially reduce the risk of falls in the future.

    REFERENCES

    1. Ma, C.Z.-H.; 2018 Top Stroke Rehabil.
    2. Ma, C.Z.-H.; 2017 Hum Mov Sci.
    3. Ma, C.Z.-H.; 2016 Sensors.
    4. Ma, C.Z.-H.; 2015 Sensors.
    5. Wan, A.-H.; 2016 Arch Phys Med Rehabil.
    6. Wu, J.; 2017 INT J PROD RES.
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    8. Gravina, R.; 2017 Future Gener Comput Syst.

     

    ACKNOWLEDGEMENTS

    This work was partially supported by The Hong Kong Polytechnic University [grant number: G-YBRN].

  • 42.
    Ma, Christina Zong-Hao
    et al.
    Högskolan i Jönköping, Hälsohögskolan, HHJ, Avd. för rehabilitering. Department of Biomedical Engineering, The Hong Kong Polytechnic University, Hong Kong.
    Ling, Yan To
    Department of Biomedical Engineering, The Hong Kong Polytechnic University.
    Shea, Queenie Tsung Kwan
    Department of Biomedical Engineering, The Hong Kong Polytechnic University.
    Wang, Li-Ke
    Department of Biomedical Engineering, The Hong Kong Polytechnic University.
    Wang, Xiao-Yun
    GuangdongWork Injury Rehabilitation Center.
    Zheng, Yong-Ping
    Department of Biomedical Engineering, The Hong Kong Polytechnic University.
    Towards Wearable Comprehensive Capture and Analysis of Skeletal Muscle Activity during Human Locomotion2019Ingår i: Sensors, ISSN 1424-8220, E-ISSN 1424-8220, Vol. 19, nr 1, artikel-id 195Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Background: Motion capture and analyzing systems are essential for understanding locomotion. However, the existing devices are too cumbersome and can be used indoors only. A newly-developed wearable motion capture and measurement system with multiple sensors and ultrasound imaging was introduced in this study. Methods: In ten healthy participants, the changes in muscle area and activity of gastrocnemius, plantarflexion and dorsiflexion of right leg during walking were evaluated by the developed system and the Vicon system. The existence of significant changes in a gait cycle, comparison of the ankle kinetic data captured by the developed system and the Vicon system, and test-retest reliability (evaluated by the intraclass correlation coefficient, ICC) in each channel’s data captured by the developed system were examined. Results: Moderate to good test-retest reliability of various channels of the developed system (0.512 ≤ ICC ≤ 0.988, p < 0.05), significantly high correlation between the developed system and Vicon system in ankle joint angles (0.638R ≤ 0.707, p < 0.05), and significant changes in muscle activity of gastrocnemius during a gait cycle (p < 0.05) were found. Conclusion: A newly developed wearable motion capture and measurement system with ultrasound imaging that can accurately capture the motion of one leg was evaluated in this study, which paves the way towards real-time comprehensive evaluation of muscles and joint motions during different activities in both indoor and outdoor environments.

  • 43.
    Ma, Christina Zong-Hao
    et al.
    Interdisciplinary Division of Biomedical Engineering, The Hong Kong Polytechnic University.
    Wan, Anson H.P.
    Interdisciplinary Division of Biomedical Engineering, The Hong Kong Polytechnic University.
    Wong, Duo W.C.
    Interdisciplinary Division of Biomedical Engineering, The Hong Kong Polytechnic University.
    Zheng, Yong-Ping
    Interdisciplinary Division of Biomedical Engineering, The Hong Kong Polytechnic University.
    Lee, Winson C.C.
    Interdisciplinary Division of Biomedical Engineering, The Hong Kong Polytechnic University.
    Improving Postural Control Using a Portable Plantar PressurebasedVibrotactile Biofeedback System2014Konferensbidrag (Refereegranskat)
    Abstract [en]

    A portable and lightweight vibrotactile biofeedback system is introduced here which acts as a real-time balance aid. The biofeedback system provided users with vibrotactile stimulation based on changes in plantar pressure distribution. An experiment was conducted to investigate its effectiveness in improvement of postural control. A Romberg test was performed requesting the subjects to stand as still as possible, while the degree of body sway was measured by a force platform. Two young healthy subjects and one older healthy subject participated in the study. A wearing wool socks and eye-closed intervention was used to simulate reduced sensory input, and the effect of provision of vibrotactile feedback was studied. The experiment was conducted in 3 conditions: 1) bare feet, eyes open (baseline), 2) wearing 5 layers of wool socks, eyes closed, 3) wearing 5 layers of socks, eyes closed, with biofeedback system turned-on. The range, root mean square (RMS) and coefficient of variance (CV) of center of pressure (COP) were studied. Results indicated a significant increase of postural sway after the intervention of reducing sensory inputs, and a considerable reduction of postural sway upon using the vibrotactile feedback reminding body motion in four directions. These results suggested that vibrotactile biofeedback system is effective in improving postural control of subjects. Future studies about the effects of this biofeedback system on dynamic balance control and gait are needed.

  • 44. Maksuti, E
    et al.
    Johnson, J
    Bjällmark, Anna
    Broomé, M
    The heart as a displacement pump: a novel cardiac model2013Konferensbidrag (Övrigt vetenskapligt)
  • 45. Maksuti, E
    et al.
    Larsson, D
    Widman, E
    Urban, M W
    Larsson, M
    Bjällmark, Anna
    Influence of confined geometries in shear wave elastography: an experimental study2015Konferensbidrag (Övrigt vetenskapligt)
  • 46.
    Maksuti, E
    et al.
    KTH Royal Institute of Technology, Stockholm, Sweden and Karolinska Institutet, Solna, Sweden.
    Larsson, D
    KTH Royal Institute of Technology, Stockholm, Sweden.
    Widman, E
    KTH Royal Institute of Technology, Stockholm, Sweden and Karolinska Institutet, Solna, Sweden.
    Urban, MW
    Mayo Clinic College of Medicine, Rochester, MN, USA.
    Larsson, M
    KTH Royal Institute of Technology, Stockholm, Sweden and Karolinska Institutet, Solna, Sweden.
    Bjällmark, Anna
    KTH Royal Institute of Technology, Stockholm, Sweden and Karolinska Institutet, Solna, Sweden.
    Accuracy of arterial shear wave elastography by phase velocity - validation with mechnical tesing in phantoms.2015Ingår i: Proceedings of the Fourteenth International Tissue Elasticity Conference, 2015Konferensbidrag (Övrigt vetenskapligt)
  • 47.
    Maksuti, E
    et al.
    Royal Institute of Technology (KTH), Stockholm, Sweden.
    Widman, E
    Royal Institute of Technology (KTH), Stockholm, Sweden.
    Larsson, M
    Royal Institute of Technology (KTH), Stockholm, Sweden.
    Bjällmark, Anna
    Royal Institute of Technology (KTH), Stockholm, Sweden.
    Caidahl, K
    Karolinska Institute, Stockholm,­ Sweden.
    D'hooge, J
    Catholic University of Leuven, Leuven, Belgium.
    Feasibility of shear wave elastography for carotid plaque characterization: a phantom study2012Ingår i: Vol. 13, nr suppl_1, s. i42-i46, artikel-id P359Artikel i tidskrift (Refereegranskat)
  • 48.
    Maksuti, Elira
    et al.
    KTH, Medicinsk avbildning.
    Johnson, Jonas
    KTH, Medicinsk avbildning.
    Bjällmark, Anna
    KTH, Medicinsk avbildning.
    Broomé, Michael
    KTH, Medicinsk avbildning.
    Physical modeling of the heart with the atrioventricular plane as a piston unit2013Konferensbidrag (Övrigt vetenskapligt)
    Abstract [en]

    Cardiac models do not often take the atrioventricular (AV) interactioninto account, even though medicalimaging and clinical studies have shown that the heart pumps with minorouter volume changes throughout the cardiac cycle and with backand forthlongitudinal movements in the AVregion. We present a novel cardiac model based on physical modeling of the heart withthe AV-plane asa piston unit. Model simulationsgeneratedrealistic outputsforpressures and flows as well asAV-piston velocity, emphasizing the relevance of myocardial longitudinal movements in cardiac function

  • 49.
    Maksuti, Elira
    et al.
    KTH, Medicinsk bildteknik.
    Widman, Erik
    KTH, Medicinsk bildteknik.
    Larsson, David
    KTH, Medicinsk bildteknik.
    Urban, Matthew W.
    Larsson, Matilda
    KTH, Medicinsk bildteknik.
    Bjällmark, Anna
    KTH, Medicinsk bildteknik.
    Arterial stiffness estimation by shear wave elastography: Validation in phantoms with mechanical testing2016Ingår i: Ultrasound in Medicine and Biology, ISSN 0301-5629, E-ISSN 1879-291X, Vol. 42, nr 1, s. 308-321Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Arterial stiffness is an independent risk factor found to correlate with a wide range of cardiovascular diseases. It has been suggested that shear wave elastography (SWE) can be used to quantitatively measure local arterial shear modulus, but an accuracy assessment of the technique for arterial applications has not yet been performed. In this study, the influence of confined geometry on shear modulus estimation, by both group and phase velocity analysis, was assessed, and the accuracy of SWE in comparison with mechanical testing was measured in nine pressurized arterial phantoms. The results indicated that group velocity with an infinite medium assumption estimated shear modulus values incorrectly in comparison with mechanical testing in arterial phantoms (6.7 +/- 0.0 kPa from group velocity and 30.5 +/- 0.4 kPa from mechanical testing). To the contrary, SWE measurements based on phase velocity analysis (30.6 +/- 3.2 kPa) were in good agreement with mechanical testing, with a relative error between the two techniques of 8.8 +/- 6.0% in the shear modulus range evaluated (40-100 kPa). SWE by phase velocity analysis was validated to accurately measure stiffness in arterial phantoms.

  • 50. Manouras, A
    et al.
    Bjällmark, Anna
    Winter, R
    Brodin, L-Å
    Color coded tissue Doppler is more accurate and less sensitive to filtering and gain settings compared to spectral tissue Doppler: A comparison of two commonly used tissue doppler techniques in the clinical setting2007Konferensbidrag (Övrigt vetenskapligt)
12 1 - 50 av 63
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