Quantitative Ultrasound Evaluation of Tissue Composition in Carotid Plaque
Catherine N. Steffel, M.S.
Carotid atherosclerotic plaque is a contributing cause of cardiovascular disease and stroke, the fifth leading cause of death worldwide. Understanding plaque morphology, including its structure, composition, and mechanical properties, may help improve risk assessments of plaque rupture and stroke. Yet current methods of characterizing plaque in-vivo, such as texture-based grayscale analyses of B-mode ultrasound images, have limitations, making widespread clinical implementation of these techniques difficult. Quantitative ultrasound (QUS) parameters use native radiofrequency (RF) data from the ultrasound system, making QUS-based techniques more suitable for implementation across studies or medical centers. Our preliminary results from four QUS parameters – attenuation coefficient, integrated backscatter, backscatter coefficient, and effective scatterer diameter – demonstrate that QUS can objectively identify plaque tissues in-vivo. For development of a risk model of carotid plaque rupture and stroke, however, a clearer understanding is needed about how in-vivo parameters relate to those in excised plaque tissue and histopathology, the gold standard for identifying plaque tissue composition. Our ongoing work lays the foundation for evaluating QUS parameters in-vivo and ex-vivo and comparing these against histopathology assessments of excised plaque specimens. These QUS parameters will guide future development of an accurate, reliable, noninvasive, and inexpensive clinical tool for assessing the risk or carotid plaque rupture or stroke. This research is performed in collaboration with the Department of Neurological Surgery, Department of Medicine, and the Department of Surgical Pathology at the University of Wisconsin School of Medicine and Public Health and is supported by
R01 and F31 grants from the National Institutes of Health.
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