Browsing NTNU Open by Author "Løvstakken, Lasse"
Now showing items 41-60 of 74
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Improved Ultrasound Blood Flow Imaging Using Model-based Regularisation
Nysted, Siri Stueland (Master thesis, 2022)Denne oppgaven består av to deler. Den første delen er en parametertest av et regulariseringsoppsett som kombinerer en fluidmekanisk modell med støyete blodhastighetsmålinger interpolert på et b-spline grid. Nøyaktigheten ... -
In vivo intracardiac vector flow imaging using phased array transducers for pediatric cardiology
Fadnes, Solveig; Wigen, Morten Smedsrud; Nyrnes, Siri Ann; Løvstakken, Lasse (Journal article; Peer reviewed, 2017)Two-dimensional blood speckle tracking (ST) has shown promise for measuring complex flow patterns in neonatal hearts using linear arrays and high-frame-rate plane wave imaging. For general pediatric applications, however, ... -
Intraventricular Vector Flow Imaging with Blood Speckle Tracking in Adults: Feasibility, Normal Physiology and Mechanisms in Healthy Volunteers
Daae, Annichen Søyland; Wigen, Morten Smedsrud; Fadnes, Solveig; Løvstakken, Lasse; Støylen, Asbjørn (Peer reviewed; Journal article, 2021)This study examines the feasibility of blood speckle tracking for vector flow imaging in healthy adults and describes the physiologic flow pattern and vortex formation in relation to the wall motion in the left ventricle. ... -
Intraventricular Vector Flow Mapping ― An In Silico and In Vivo Evaluation
Sælensminde, Magnus (Master thesis, 2018)Modern cardiology research aims to encompass sophisticated analysis of intraventricular blood flow in the clinical practice. Such analysis relies on robust and effective means of measuring blood flow fields, an approach ... -
Machine Learning for Classification of Myocardial Infarction and Heart failure Using Longitudinal Myocardial Strain
Sandvik, Yohann Jacob (Master thesis, 2020)Venstre-ventrikkels ejeksjonsfraksjon (EF) har lenge blitt brukt som en indikator på hjertetilstand av pasienter i klinisk kardiologi. De siste årene har bruken av myokardiell tøyning til diagnostikk også blitt mer utbredt. ... -
Mechanical wave velocities in left ventricular walls – in healthy subjects and patients with aortic stenosis
Espeland, Torvald; Wigen, Morten Smedsrud; Dalen, Håvard; Berg, Erik Andreas Rye; Hammer, Tommy Arild; Salles, Sebastien Andre Roger; Løvstakken, Lasse; Amundsen, Brage H.; Aakhus, Svend (Peer reviewed; Journal article, 2023)Background Mechanical wave velocity (MWV) measurement is a promising method for evaluating myocardial stiffness, because these velocities are higher in patients with myocardial disease. Objectives Using high frame ... -
Minimally invasive beat-by-beat monitoring of cardiac power in normal hearts and during acute ventricular dysfunction
Rimehaug, Audun Eskeland; Skogvoll, Eirik; Aadahl, Petter; Lyng, Oddveig; Nordhaug, Dag Ole; Løvstakken, Lasse; Kirkeby-Garstad, Idar (Journal article; Peer reviewed, 2016)Cardiac power, the product of aortic flow and blood pressure, appears to be a fundamental cardiovascular parameter. The simplified version named cardiac power output (CPO), calculated as the product of cardiac output (CO) ... -
Model-Based Estimation of Intracardiac Blood Flow Velocity Patterns Based on Ultrasound Imaging
Høgenes, Jakob (Master thesis, 2015)There is a general concession within the field of cardiology that deeper knowledge of the complex intracardiac blood flow patterns would likely lead to improved methods for diagnosing cardiovascular diseases and deficiencies. ... -
Modeling and data assimilation for improved ultrasound measurement of blood velocity fields
Grønli, Thomas (Master thesis, 2017)Cardiovascular disease is the leading cause of death worldwide, and echocardiography stands as a fundamental tool in assessing congenital or developed heart failure. A cornerstone of echocardiography is the ability to ... -
Myocardial Function Imaging in Echocardiography Using Deep Learning
Østvik, Andreas; Salte, Ivar Mjåland; Smistad, Erik; Nguyen, Thuy Mi; Melichova, Daniela; Brunvand, Harald; Haugaa, Kristina; Edvardsen, Thor; Grenne, Bjørnar; Løvstakken, Lasse (Journal article; Peer reviewed, 2021)Deformation imaging in echocardiography has been shown to have better diagnostic and prognostic value than conventional anatomical measures such as ejection fraction. However, despite clinical availability and demonstrated ... -
Navigated Ultrasound Imaging: 3D Reconstruction of Artery Geometry and Flow
Karabiyik, Yücel (Master thesis, 2013)Atherosclerosis is a disease in which plaque builds up inside the arteries and causes the arteries to harden and narrow. The diagnosis of atherosclerosis and quantification of the extent of atherosclerosis nowadays depend ... -
Optimization of Ultrasound Signal and Image Processing Using the Tensorflow Framework
Babar, Abdullah Zahir (Master thesis, 2021)Ultralyd er et av de mest brukte avbildnings-systemene som brukes innenfor det medisinske feltet. Det er et ikke-invasivt og allsidig diagnostisk verktøy som går igjennom flere prosesseringstrinn før det omdanner et bilde ... -
Optimizing Transmit Sequence for Ultrafast Ultrasound Imaging
Ravn, Sondre Strand (Master thesis, 2017)A simulation tool developed for estimating the acoustic properties of different transmit beams and sequences, based on FieldSim and the linear simulator Field2, is presented. For defocused and unfocused beams, some ... -
Pulmonary Hypertension in Children is associated with Abnormal Flow patterns in the Main Pulmonary Artery as demonstrated by Blood Speckle Tracking
Mawad, Wadi; Fadnes, Solveig; Løvstakken, Lasse; Henry, Matthew; Mertens, Luc; Nyrnes, Siri Ann (Journal article; Peer reviewed, 2022)Background Paediatric pulmonary arterial hypertension (PAH) is characterized by increased pulmonary vascular resistance resulting in increased pulmonary artery (PA) and right ventricular pressure (RV). This is associated ... -
Quantifying Valve Regurgitation using 3-D Doppler Ultrasound Images and Deep Learning
Wifstad, Sigurd Vangen; Løvstakken, Lasse; Avdal, Jørgen; Berg, Erik Andreas Rye; Torp, Hans; Grenne, Bjørnar; Fiorentini, Stefano (Peer reviewed; Journal article, 2022)Accurate quantification of cardiac valve regurgitation jets is fundamental for guiding treatment. Cardiac ultrasound is the preferred diagnostic tool, but current methods for measuring the regurgitant volume (RVol) are ... -
Quantifying Valve Regurgitation Using 3-D Doppler Ultrasound Images and Deep Learning
Wifstad, Sigurd Vangen; Løvstakken, Lasse; Avdal, Jørgen; Berg, Erik Andreas Rye; Torp, Hans; Grenne, Bjørnar; Fiorentini, Stefano (Peer reviewed; Journal article, 2022)Accurate quantification of cardiac valve regurgitation jets is fundamental for guiding treatment. Cardiac ultrasound is the preferred diagnostic tool, but current methods for measuring the regurgitant volume are limited ... -
Quantitative Doppler analysis using color flow imaging and adaptive signal processing
Karabiyik, Yücel (Doctoral theses at NTNU;2017:227, Doctoral thesis, 2017)Kvantitative Doppler-m˚alinger fra farge-Doppler ved bruk av adaptiv signalprosessering Medisinsk ultralyd er et viktig verktøy i obstetrikk for ˚a vurdere mors helse og fosterets utvikling gjennom svangerskapet. ... -
Real-Time Automatic Ejection Fraction and Foreshortening Detection Using Deep Learning
Smistad, Erik; Salte, Ivar Mjåland; Østvik, Andreas; Melichova, Daniela; Nguyen, Thuy Mi; Haugaa, Kristina; Brunvand, Harald; Edvardsen, Thor; Leclerc, Sarah; Bernard, Olivier; Grenne, Bjørnar; Løvstakken, Lasse (Peer reviewed; Journal article, 2020)Volume and ejection fraction (EF) measurements of the left ventricle (LV) in 2-D echocardiography are associated with a high uncertainty not only due to interobserver variability of the manual measurement, but also due to ... -
Real-time automatic quantification of left ventricular function by hand-held ultrasound devices in patients with suspected heart failure: a feasibility study of a diagnostic test with data from general practitioners, nurses and cardiologists
Hjorth-Hansen, Anna; Magelssen, Malgorzata Isabela; Andersen, Garrett Newton; Graven, Torbjørn; Kleinau, Jens Olaf; Landstad, Bodil; Løvstakken, Lasse; Skjetne, Kyrre; Mjølstad, Ole Christian; Dalen, Håvard (Peer reviewed; Journal article, 2022)Objectives To evaluate the feasibility and reliability of hand-held ultrasound (HUD) examinations with real-time automatic decision-making software for ejection fraction (autoEF) and mitral annular plane systolic excursion ... -
Real-Time Echocardiography Guidance for Optimized Apical Standard Views
Pasdeloup, David Francis Pierre; Olaisen, Sindre Hellum; Østvik, Andreas; Sæbø, Sigbjørn; Pettersen, Håkon Neergaard; Holte, Espen; Grenne, Bjørnar; Stølen, Stian Bergseng; Smistad, Erik; Aase, Svein Arne; Dalen, Håvard; Løvstakken, Lasse (Journal article; Peer reviewed, 2022)