Improved Beamforming for Lateral Oscillations in Elastography Using Synthetic Aperture Imaging

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Videodensitometric analysis of advanced carotid plaque: correlation with MMP-9 and TIMP-1 expression

<p>Abstract</p> <p>Background</p> <p>Matrix metalloproteinase-9 (MMP-9) and tissue inhibitor of MMP (TIMP) promote derangement of the extracellular matrix, which is ultimately reflected in plaque images seen on ultrasound. Videodensitometry can identify structural disturbances in plaques.</p> <p>Objectives</p> <p>To establish the correlations between values determined using videodensitometry in B-mode ultrasound images of advanced carotid plaques and the total expression of MMP-9 and TIMP-1 in these removed plaques.</p> <p>Methods</p> <p>Thirty patients underwent ultrasonic tissue characterization of carotid plaques before surgery, using mean gray level (MGL), energy, entropy and homogeneity. Each patient was assigned preoperatively to one of 2 groups: group I, symptomatic patients (n = 16; 12 males; mean age 66.7 ± 6.8 years), and group II, asymptomatic patients (n = 14; 8 males; mean age 67.6 ± 6.81 years). Tissue specimens were analyzed for MMP-9 and TIMP-1 expression. Nine carotid arteries were used as normal tissue controls.</p> <p>Results</p> <p>MMP-9 expression levels were elevated in group II and in normal tissues compared to group I (p < 0.001). TIMP-1 levels were higher in group II than in group I, and significantly higher in normal tissues than in group I (p = 0.039). The MGL was higher in group II compared to group I (p = 0.038). Energy had greater values in group II compared to group I (<it>p </it>= 0.02). There were no differences between patient groups in homogeneity and entropy. Energy positively correlated with MMP-9 and TIMP-1 expression (p = 0.012 and p = 0.031 respectively). Homogeneity positively correlated with MMP-9 and TIMP-1 expression (p = 0.034 and p = 0.047 respectively). There were no correlations between protein expression and MGL or entropy.</p> <p>Conclusions</p> <p>Videodensitometric computer analysis of ultrasound scanning images can be used to identify stable carotid plaques, which have higher total expression levels of MMP-9 and TIMP-1 than unstable plaques.</p

Ultrasound Spatial Compound Scanner for Improved Visualization in Vascular Imaging

A new off-line multi-angle ultrasound compound scanner has been built with the aim of improving visualization of vascular tissue. Images are recorded from 3 to 11 insonification angles over a range of 40 to 50 degrees and the individual images are combined (averaged) into a single image (spatial compounding). Compared to conventional B-mode imaging, this multi-angle compound imaging (MACI) method features less angle-dependent images, since more scan lines are nearly perpendicular to the tissue interfaces. Further, the spatial compounding strongly diminishes the speckle pattern. These improvements are illustrated with in vitro images of porcine aorta and human atherosclerotic plaque. 1 . Introduction The presence of atherosclerotic lesions (plaque) in the carotid arteries increases the risk of stroke, but surgical removal of the plaque has proven beneficial in reducing the risk of stroke. [2] However, ultrasonic assessment of size, shape and type of the carotid atherosclerotic lesio..

Direct estimation of the lateral strain field using a double oscillating point spread function with a scaling factor estimator

International audienc