• A fast 4D B-spline framework for model-based reconstruction and regularization in vector flow imaging 

      Grønli, Thomas; Wigen, Morten Smedsrud; Segers, Patrick; Løvstakken, Lasse (Journal article; Peer reviewed, 2018)
      A generic framework for model-based regularization and reconstruction is described, with applications in a wide range of noisy measurement scenarios. The framework employs automatic differentiation and stochastic gradient ...
    • Annotation Web - An open-source web-based annotation tool for ultrasound images 

      Smistad, Erik; Østvik, Andreas; Løvstakken, Lasse (Peer reviewed; Journal article, 2021)
      The use of deep learning and other machine learning techniques requires large amounts of annotated image data. There exist several tools to annotate images, however to our knowledge there are no tools made specifically for ...
    • Design, Fabrication and Testing Highly Sensitive Single Element Doppler Transducers 

      Bolstad, Per Kristian; Hoff, Lars; Torp, Hans; Johansen, Tonni Franke (Journal article; Peer reviewed, 2018)
      Three common piezoelectric materials have been studied for use in pulsed wave Doppler ultrasound, where high sensitivity is required, while bandwidth is less important. A large transducer aperture, 80 mm 2 , results in a ...
    • Detailed flow visualization in fetal and neonatal hearts using 2-D speckle tracking 

      Fadnes, Solveig; Nyrnes, Siri Ann; Wigen, Morten Smedsrud; Tegnander, Eva; Løvstakken, Lasse (Journal article, 2016)
      Two-dimensional blood speckle tracking has shown promise for measuring the complex flow patterns in neonatal hearts when based on linear array and high-frame-rate plane wave imaging. For phased array pediatric imaging, ...
    • Fully automatic real-time ejection fraction and MAPSE measurements in 2D echocardiography using deep neural networks 

      Smistad, Erik; Østvik, Andreas; Salte, Ivar Mjåland; Leclerc, Sarah; Bernard, Olivier; Løvstakken, Lasse (Journal article; Peer reviewed, 2018)
      Cardiac ultrasound measurements such as left ventricular volume, ejection fraction (EF) and mitral annular plane systolic excursion (MAPSE) are time consuming and highly observer dependent. In this work, we investigate if ...
    • Improved Lesion Detection Using Nonlocal Means Post-Processing 

      Rindal, Ole Marius Hoel; Rodriguez-Molares, Alfonso; Måsøy, Svein-Erik; Bjåstad, Tore Grüner (Journal article; Peer reviewed, 2019)
      Software beamforming allows more flexible and complex algorithms, often referred to as adaptive beamforming techniques, that are blurring the boundaries between beamforming and image processing. Many adaptive beamforming ...
    • Real-time 3D left ventricle segmentation and ejection fraction using deep learning 

      Smistad, Erik; Steinsland, Erik Nikolai; Løvstakken, Lasse (Peer reviewed; Journal article, 2021)
      Supervised learning for 3D left ventricle (LV) ultrasound segmentation is difficult due to the challenges of acquiring large amounts annotated data. In this work, pre-training on a weakly labeled dataset, combined with ...
    • Real-time segmentation of blood vessels, nerves and bone in ultrasound-guided regional anesthesia using deep learning 

      Smistad, Erik; Lie, Torgrim; Johansen, Kaj Fredrik (Peer reviewed; Journal article, 2021)
      Images from ultrasound-guided regional anesthesia procedures can be difficult to interpret, especially by non-experts. In this work, deep convolutional neural networks were used to segment blood vessels, nerves and bone ...
    • Real-time temporal coherent left ventricle segmentation using convolutional LSTMs 

      Smistad, Erik; Salte, Ivar Mjåland; Dalen, Håvard; Løvstakken, Lasse (Peer reviewed; Journal article, 2021)
    • Segmentation of parasternal long axis views using deep learning 

      Smistad, Erik; Dalen, Håvard; Grenne, Bjørnar; Løvstakken, Lasse (Journal article; Peer reviewed, 2022)
    • The dark region artifact in adaptive ultrasound beamforming 

      Rindal, Ole Marius Hoel; Rodriguez-Molares, Alfonso; Austeng, Andreas (Journal article; Peer reviewed, 2017)
      An undesired effect, the dark region artifact (DRA), has been under-communicated in our research community. The DRA appear next to acoustically strong targets for some of the many adaptive beamformers introduced in the ...
    • The Effect of Sonication on Extravasation and Distribution of Nanoparticles and Dextrans in Tumor Tissue Imaged by Multiphoton Microscopy 

      Yemane, Petros Tesfamichael; Åslund, Andreas; Sæterbø, Kristin Grendstad; Bjørkøy, Astrid; Snipstad, Sofie; van Wamel, Annemieke; Berg, Sigrid; Mørch, Ýrr Asbjørg; Hansen, Rune; Angelsen, Bjørn Atle Johan; Davies, Catharina de Lange (Journal article; Peer reviewed, 2018)
      Ultrasound (US)and systemic administration of microbubbles (MBs)have been shown to improve the delivery of drugs and nanoparticles (NPs)to tumor tissue. A better understanding of the mechanisms is crucial for effective ...
    • The influence of speckle statistics on contrast metrics in ultrasound imaging 

      Hverven, Stine Myhre; Rindal, Ole Marius Hoel; Rodriguez-Molares, Alfonso; Austeng, Andreas (Journal article; Peer reviewed, 2017)
      Adaptive beamformers aim for improved resolution and contrast in the ultrasound images, and their performance is typically benchmarked using metrics such as contrast ratio (CR) and contrast-to-noise ratio (CNR). Using ...
    • The UltraSound ToolBox 

      Rodriguez-Molares, Alfonso; Rindal, Ole Marius Hoel; Bernard, Olivier; Nair, Arun; Bell, Muyinatu A. Lediju; Liebgott, Herve; Austeng, Andreas; Løvstakken, Lasse (Journal article; Peer reviewed, 2017)
      We present the UltraSound ToolBox (USTB), a processing framework for ultrasound signals. USTB aims to facilitate the comparison of imaging techniques and the dissemination of research results. It fills the void of tools ...
    • Tracking-based mitral annular plane systolic excursion (MAPSE) measurement using deep learning in B-mode ultrasound 

      Smistad, Erik; Østvik, Andreas; Grue, Jahn Frederik; Dalen, Håvard; Løvstakken, Lasse (Peer reviewed; Journal article, 2022)
      Mitral annular plane systolic excursion (MAPSE) is an important measure of left ventricular function. Current clinical practice is to measure it manually using M-mode ultrasound imaging which has several disadvantages such ...
    • Ultrasonic focusing through a steel layer for acoustic imaging 

      Talberg, Andreas Sørbrøden; Dong, Hefeng; Johansen, Tonni Franke; Måsøy, Svein-Erik; Brekke, Svein; Rommetveit, Tarjei (Journal article; Peer reviewed, 2018)
      Ultrasonic tools are being used for imaging in a large variety of fields, spanning from medical applications in a hospital to applications deep down in oil and gas wells. When applying ultrasonic imaging techniques to image ...
    • Ultrasound speckle reduction using generative adversial networks 

      Dietrichson, Fabian Sødal; Smistad, Erik; Østvik, Andreas; Løvstakken, Lasse (Journal article; Peer reviewed, 2018)
      Generative adversial networks (GANs) have shown its ability to create realistic and accurate image-to-image transformation. The goal of this work was to investigate whether deep convolutional GANs can learn to perform ...