@article{torres_czernuszewicz_homeister_caughey_huang_lee_zamora_farber_marston_huang_et al._2019, title={Delineation of Human Carotid Plaque Features In Vivo by Exploiting Displacement Variance}, volume={66}, ISSN={["1525-8955"]}, DOI={10.1109/TUFFC.2019.2898628}, abstractNote={While in vivo acoustic radiation force impulse (ARFI)-induced peak displacement (PD) has been demonstrated to have high sensitivity and specificity for differentiating soft from stiff plaque components in patients with carotid plaque, the parameter exhibits poorer performance for distinguishing between plaque features with similar stiffness. To improve discrimination of carotid plaque features relative to PD, we hypothesize that signal correlation and signal-to-noise ratio (SNR) can be combined, outright or via displacement variance. Plaque feature detection by displacement variance, evaluated as the decadic logarithm of the variance of acceleration and termed “log(VoA),” was compared to that achieved by exploiting SNR, cross correlation coefficient, and ARFI-induced PD outcome metrics. Parametric images were rendered for 25 patients undergoing carotid endarterectomy, with spatially matched histology confirming plaque composition and structure. On average, across all plaques, log(VoA) was the only outcome metric with values that statistically differed between regions of lipid-rich necrotic core (LRNC), intraplaque hemorrhage (IPH), collagen (COL), and calcium (CAL). Further, log(VoA) achieved the highest contrast-to-noise ratio (CNR) for discriminating between LRNC and IPH, COL and CAL, and grouped soft (LRNC and IPH) and stiff (COL and CAL) plaque components. More specifically, relative to the previously demonstrated ARFI PD parameter, log(VoA) achieved 73% higher CNR between LRNC and IPH and 59% higher CNR between COL and CAL. These results suggest that log(VoA) enhances the differentiation of LRNC, IPH, COL, and CAL in human carotid plaques, in vivo, which is clinically relevant to improving stroke risk prediction and medical management.}, number={3}, journal={IEEE TRANSACTIONS ON ULTRASONICS FERROELECTRICS AND FREQUENCY CONTROL}, author={Torres, Gabriela and Czernuszewicz, Tomasz J. and Homeister, Jonathon W. and Caughey, Melissa C. and Huang, Benjamin Y. and Lee, Ellie R. and Zamora, Carlos A. and Farber, Mark A. and Marston, William A. and Huang, David Y. and et al.}, year={2019}, month={Mar}, pages={481–492} }
 @article{kleinstreuer_li_basciano_seelecke_farber_2008, title={Computational mechanics of Nitinol stent grafts}, volume={41}, ISSN={["1873-2380"]}, DOI={10.1016/j.jbiomech.2008.05.032}, abstractNote={A finite element analysis of tubular, diamond-shaped stent grafts under representative cyclic loading conditions for abdominal aortic aneurysm (AAA) repair is presented. Commercial software was employed to study the mechanical behavior and fatigue performance of different materials found in commercially available stent-graft systems. Specifically, the effects of crimping, deployment, and cyclic pressure loading on stent-graft fatigue life, radial force, and wall compliances were simulated and analyzed for two types of realistic but different Nitinol materials (NITI-1 and NITI-2) and grafts (expanded polytetrafluoroethylene-ePTFE and polyethylene therephthalate-PET). The results show that NITI-1 stent has a better crimping performance than NITI-2. Under representative cyclic pressure loading, both NITI-1 and NITI-2 sealing stents are located in the safe zone of the fatigue-life diagram; however, the fatigue resistance of an NITI-1 stent is better than that of an NITI-2 stent. It was found that the two types of sealing stents do not damage a healthy neck artery. In the aneurysm section, the NITI-1&ePTFE, NITI-1&PET, and NITI-2&PET combinations were free of fatigue fracture when subjected to conditions of radial stress between 50 and 150mmHg. In contrast, the safety factor for the NITI-2&ePFTE combination was only 0.67, which is not acceptable for proper AAA stent-graft design. In summary, a Nitinol stent with PET graft may greatly improve fatigue life, while its compliance is much lower than the NITI-ePTFE combination.}, number={11}, journal={JOURNAL OF BIOMECHANICS}, author={Kleinstreuer, C. and Li, Z. and Basciano, C. A. and Seelecke, S. and Farber, M. A.}, year={2008}, month={Aug}, pages={2370–2378} }