Marko Jakovljevic

Publications (2)3.82 Total impact

• Article: In Vivo Application of Short-Lag Spatial Coherence Imaging in Human Liver.

  Marko Jakovljevic, Gregg E Trahey, Rendon C Nelson, Jeremy J Dahl
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  ABSTRACT: We present the results of a patient study conducted to assess the performance of two novel imaging methods, namely short-lag spatial coherence (SLSC) and harmonic spatial coherence imaging (HSCI), in an in vivo liver environment. Similar in appearance to the B-mode images, SLSC and HSCI images are based solely on the spatial coherence of fundamental and harmonic echo data, respectively, and do not depend on the echo magnitude. SLSC and HSCI suppress incoherent echo signals and thus tend to reduce clutter. The SLSC and HSCI images of 17 patients demonstrated sharper delineation of blood vessel walls, suppressed clutter inside the vessel lumen, and showed reduced speckle in surrounding tissue compared to matched B-modes. Target contrast and contrast-to-noise ratio (CNR) show statistically significant improvements between fundamental B-mode and SLSC imaging and between harmonic B-mode and HSCI imaging (in all cases p < 0.001). The magnitude of improvement in contrast and CNR increases as the overall quality of B-mode images decreases. Poor-quality fundamental B-mode images (where image quality classification is based on both contrast and CNR) exhibit the highest improvements in both contrast and CNR (288% improvement in contrast and 533% improvement in CNR).
  Ultrasound in medicine & biology 01/2013; · 2.02 Impact Factor
• Article: Harmonic spatial coherence imaging: an ultrasonic imaging method based on backscatter coherence.

  Jeremy Dahl, Marko Jakovljevic, Gianmarco F Pinton, Gregg E Trahey
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  ABSTRACT: We introduce a harmonic version of the short-lag spatial coherence (SLSC) imaging technique, called harmonic spatial coherence imaging (HSCI). The method is based on the coherence of the second-harmonic backscatter. Because the same signals that are used to construct harmonic B-mode images are also used to construct HSCI images, the benefits obtained with harmonic imaging are also obtained with HSCI. Harmonic imaging has been the primary tool for suppressing clutter in diagnostic ultrasound imaging, however secondharmonic echoes are not necessarily immune to the effects of clutter. HSCI and SLSC imaging are less sensitive to clutter because clutter has low spatial coherence. HSCI shows favorable imaging characteristics such as improved contrast-to-noise ratio (CNR), improved speckle SNR, and better delineation of borders and other structures compared with fundamental and harmonic B-mode imaging. CNRs of up to 1.9 were obtained from in vivo imaging of human cardiac tissue with HSCI, compared with 0.6, 0.9, and 1.5 in fundamental B-mode, harmonic B-mode, and SLSC imaging, respectively. In vivo experiments in human liver tissue demonstrated SNRs of up to 3.4 for HSCI compared with 1.9 for harmonic B-mode. Nonlinear simulations of a heart chamber model were consistent with the in vivo experiments.
  IEEE transactions on ultrasonics, ferroelectrics, and frequency control 04/2012; 59(4):648-59. · 1.80 Impact Factor