Blar i Fakultet for medisin og helsevitenskap (MH) på tidsskrift "IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control"

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    • Clutter Filter Wave Imaging 

      Salles, Sebastien; Løvstakken, Lasse; Aase, Svein Arne; Bjåstad, Tore Grüner; Torp, Hans (Journal article; Peer reviewed, 2019)
      The elastic properties of human tissue can be evaluated through the study of mechanical wave propagation captured using high frame rate ultrasound imaging. Methods such as block-matching or phase-based motion estimation ...

    • Combined 2-D Vector imaging and Tracking Doppler for improved vascular blood velocity quantification 

      Avdal, Jørgen; Løvstakken, Lasse; Torp, Hans; Ekroll, Ingvild Kinn (Journal article; Peer reviewed, 2017)
      Measurement of the maximum blood flow velocity is the primary means for determining the degree of carotid stenosis using ultrasound. The current standard for estimating the maximum velocity is Pulsed Wave (PW) Doppler with ...

    • Combining Automatic Angle Correction and 3-D Tracking Doppler for the Assessment of Aortic Stenosis Severity 

      Fiorentini, Stefano; Espeland, Torvald; Berg, Erik Andreas Rye; Aakhus, Svend; Torp, Hans; Avdal, Jørgen (Journal article; Peer reviewed, 2019)
      Aortic valve stenosis (AS) is a narrowing of the aortic valve opening, which causes increased load on the left ventricle. Untreated, this condition can eventually lead to heart failure and death. According to current ...

    • Data Adaptive 2-D Tracking Doppler for High-Resolution Spectral Estimation 

      Karabiyik, Yücel; Avdal, Jørgen; Ekroll, Ingvild Kinn; Fiorentini, Stefano; Torp, Hans; Løvstakken, Lasse (Peer reviewed; Journal article, 2019)
      Spectral broadening in pulsed-wave Doppler caused by the transit-time effect deteriorates the frequency resolution and may cause overestimation of maximum velocities in high-velocity blood flow regions and for large ...

    • Effect of acoustic radiation force on displacement of nanoparticles in collagen gels 

      Løvmo, Mia Kvåle; Yemane, Petros Tesfamichael; Bjørkøy, Astrid; Hansen, Rune; Cleveland, Robin O.; Angelsen, Bjørn Atle Johan; Davies, Catharina de Lange (Peer reviewed; Journal article, 2020)
      Penetration of nanoscale therapeutic agents into the extracellular matrix (ECM) of a tumor is a limiting factor for the sufficient delivery of drugs in tumors. Ultrasound (US) in combination with microbubbles causing ...

    • Effect of Acoustic Radiation Force on the Distribution of Nanoparticles in Solid Tumors. 

      Afadzi, Mercy; Myhre, Ola Finneng; Yemane, Petros Tesfamichael; Bjørkøy, Astrid; Torp, Sverre Helge; van Wamel, Annemieke; Lelu, Sylvie; Angelsen, Bjørn Atle Johan; Davies, Catharina de Lange (Peer reviewed; Journal article, 2020)
      Acoustic radiation force (ARF) might improve the distribution of nanoparticles (NPs) in tumors. To study this, tumors growing subcutaneously in mice were exposed to focused ultrasound (FUS) either 15 min or 4 h after the ...

    • The Generalized Contrast-to-Noise Ratio: A Formal Definition for Lesion Detectability 

      Molares, Alfonso Rodrígues; Rindal, Ole Marius Hoel; D´Hooge, Jan; Måsøy, Svein-Erik; Austeng, Andreas; Bell, Muyinatu A. Lediju; Torp, Hans (Peer reviewed; Journal article, 2020)
      In the last 30 years, the contrast-to-noise ratio (CNR) has been used to estimate the contrast and lesion detectability in ultrasound images. Recent studies have shown that the CNR cannot be used with modern beamformers, ...

    • 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, ...

    • Maximum velocity estimation in coronary arteries using 3D tracking Doppler 

      Fiorentini, Stefano; Saxhaug, Lars Mølgaard; Holte, Espen; Bjåstad, Tore Grüner; Torp, Hans; Avdal, Jørgen (Journal article, 2018)
      Several challenges currently prevent the use of Doppler echocardiography to assess blood flow in the coronary arteries. Due to the anatomy of the coronary tree, out-of-plane flow and high beam-to-flow angles easily occur. ...

    • Primary Porcine Brain Endothelial Cells as In Vitro Model to Study Effects of Ultrasound and Microbubbles on Blood-Brain Barrier Function 

      Lelu, Sylvie; Afadzi, Mercy; Berg, Sigrid; Åslund, Andreas; Torp, Sverre Helge; Sattler, Wolfgang; Davies, Ruth Catharina de Lange (Journal article; Peer reviewed, 2017)
      Focused ultrasound in the presence of microbubbles transiently and reversibly opens the blood-brain barrier (BBB) in rodents and humans thereby providing a time window for increased drug delivery into brain tissue. To get ...

    • 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 ...

    • 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 ...

    • Retrospective Transmit beamforming and Coherent Plane-Wave Compounding for Microvascular Doppler Imaging: A Comparison Study 

      Golfetto, Cristiana; Ekroll, Ingvild Kinn; Torp, Hans; Løvstakken, Lasse; Avdal, Jørgen (Peer reviewed; Journal article, 2020)
      Imaging blood flow in small vessels is of great clinical value for evaluating increased vascularization, potentially related to angiogenesis in cancer or inflammation processes in musculoskeletal disease. Using a traditional ...

    • SURF Imaging Beams in an Aberrative Medium: Generation and Postprocessing Enhancement 

      Näsholm, Sven Peter; Angelsen, Bjørn Atle J. (Peer reviewed; Journal article, 2012)
      This paper presents numerical simulations of dual-frequency second-order ultrasound field (SURF) reverberation suppression transmit-pulse complexes. Such propagation was previously studied in a homogeneous medium. In this ...

    • Tapered Vector Doppler for Improved Quantification of Low Velocity Blood Flow 

      Ekroll, Ingvild Kinn; Perrot, Vincent; Liebgott, Herve; Avdal, Jørgen (Peer reviewed; Journal article, 2020)
      A new vector velocity estimation scheme is developed, termed Tapered Vector Doppler (TVD), aiming to improve the accuracy of low velocity flow estimation. This is done by assessing the effects of Singular Value Decompostion ...

    • Transmit Beams Adapted to Reverberation Noise Suppression Using Dual-Frequency SURF Imaging 

      Näsholm, Sven Peter; Hansen, Rune; Måsøy, Svein-Erik; Johansen, Tonni Franke; Angelsen, Bjørn Atle J. (Peer reviewed; Journal article, 2009)
      A method that uses dual-frequency pulse complexes of widely separated frequency bands to suppress noise caused by multiple scattering or multiple reflections in medical ultrasound imaging is presented. The excitation pulse ...

    • A Very Large Cardiac Channel Data Database (VLCD) Used to Evaluate Global Image Coherence (GIC) as an In Vivo Image Quality Metric 

      Rindal, Ole Marius Hoel; Bjåstad, Tore Grüner; Espeland, Torvald; Berg, Erik Andreas Rye; Måsøy, Svein-Erik (Peer reviewed; Journal article, 2023)
      Ultrasound image quality is of utmost importance for a clinician to reach a correct diagnosis. Conventionally, image quality is evaluated using metrics to determine the contrast and resolution. These metrics require ...