Browsing by Author "Mehta, Shail Maharshi"
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Item Assessment of spinal cord injury using ultrasound elastography in a rabbit model in vivo(Springer Nature, 2023) Tang, Songyuan; Weiner, Bradley; Taraballi, Francesca; Haase, Candice; Stetco, Eliana; Mehta, Shail Maharshi; Shajudeen, Peer; Hogan, Matthew; De Rosa, Enrica; Horner, Philip J.; Grande-Allen, K. Jane; Shi, Zhaoyue; Karmonik, Christof; Tasciotti, Ennio; Righetti, RaffaellaThe effect of the mechanical micro-environment on spinal cord injury (SCI) and treatment effectiveness remains unclear. Currently, there are limited imaging methods that can directly assess the localized mechanical behavior of spinal cords in vivo. In this study, we apply new ultrasound elastography (USE) techniques to assess SCI in vivo at the site of the injury and at the time of one week post injury, in a rabbit animal model. Eleven rabbits underwent laminectomy procedures. Among them, spinal cords of five rabbits were injured during the procedure. The other six rabbits were used as control. Two neurological statuses were achieved: non-paralysis and paralysis. Ultrasound data were collected one week post-surgery and processed to compute strain ratios. Histologic analysis, mechanical testing, magnetic resonance imaging (MRI), computerized tomography and MRI diffusion tensor imaging (DTI) were performed to validate USE results. Strain ratios computed via USE were found to be significantly different in paralyzed versus non-paralyzed rabbits. The myelomalacia histologic score and spinal cord Young’s modulus evaluated in selected animals were in good qualitative agreement with USE assessment. It is feasible to use USE to assess changes in the spinal cord of the presented animal model. In the future, with more experimental data available, USE may provide new quantitative tools for improving SCI diagnosis and prognosis.Item Demonstration of Piecewise Cubic Polynomial Fitting on Mesoscale Tester Data(Rice University, 2020) Mehta, Shail Maharshi; De Santos, Diego Ricardo; Sridhar, Shweta; Aguayo, Veronica Cristina; Meraz, Carlos Alberto; Mikos, Mary; Grande-Allen, K. Jane; BioengineeringAnimation of piecewise cubic polynomial fitting to data from a replicate of 1:15 PDMS performed in order to obtain stress values at exact increments of strainItem Development of 3D Printed Mitral Valve Constructs for Transcatheter Device Modeling of Tissue and Device Deformation(Springer Nature, 2022) Vukicevic, Marija; Mehta, Shail Maharshi; Grande-Allen, K. Jane; Little, Stephen H.Transcatheter mitral valve repair (TMVR) therapies offer a minimally invasive alternative to surgical mitral valve (MV) repair for patients with prohibitive surgical risks. Pre-procedural planning and associated medical device modeling is primarily performed in silico, which does not account for the physical interactions between the implanted TMVR device and surrounding tissue and may result in poor outcomes. We developed 3D printed tissue mimics for modeling TMVR therapies. Structural properties of the mitral annuli, leaflets, and chordae were replicated from multi-material blends. Uniaxial tensile testing was performed on the resulting composites and their mechanical properties were compared to those of their target native components. Mimics of the MV annulus printed in homogeneous strips approximated the tangent moduli of the native mitral annulus at 2% and 6% strain. Mimics of the valve leaflets printed in layers of different stiffnesses approximated the force–strain and stress–strain behavior of native MV leaflets. Finally, mimics of the chordae printed as reinforced cylinders approximated the force–strain and stress–strain behavior of native chordae. We demonstrated that multi-material 3D printing is a viable approach to the development of tissue phantoms, and that printed patient-specific geometries can approximate the local deformation force which may act upon devices used for TMVR therapies.Item Parts List, Prices, and Links for Commercial Components of Mesoscale Testing Device(Rice University, 2020) Mehta, Shail Maharshi; De Santos, Diego Ricardo; Sridhar, Shweta; Aguayo, Veronica Cristina; Meraz, Carlos Alberto; Mikos, Mary; Grande-Allen, K. Jane; BioengineeringFile displaying names, prices, quantities, and purchasing links of commercial components of mesoscale testing deviceItem Pixel Selection Demonstration Video of 1:10 PDMS from Mesoscale Testing Device on Fluorescence Microscope(Rice University, 2020) Mehta, Shail Maharshi; De Santos, Diego Ricardo; Sridhar, Shweta; Aguayo, Veronica Cristina; Meraz, Carlos Alberto; Mikos, Mary; Grande-Allen, K. Jane; BioengineeringTesting video taken using a fluorescence microscope at 10x magnification of 1:10 PDMS demonstrating which pixels are selected as belonging to edges to be tracked in yellow. Only every other pixel was checked for the appropriate color to reduce processing timeItem Pixel Selection Demonstration Video of 1:15 PDMS from Mesoscale Testing Device(Rice University, 2020) Mehta, Shail Maharshi; De Santos, Diego Ricardo; Sridhar, Shweta; Aguayo, Veronica Cristina; Meraz, Carlos Alberto; Mikos, Mary; Grande-Allen, K. Jane; BioengineeringTesting video taken using a stereomicroscope at 0.63x magnification of 1:15 PDMS demonstrating which pixels are selected as belonging to points to be tracked in yellow. Only every other pixel was checked for the appropriate color to reduce processing timeItem Print and CAD Files for Mesoscale Testing Device(Rice University, 2020) Mehta, Shail Maharshi; De Santos, Diego Ricardo; Sridhar, Shweta; Aguayo, Veronica Cristina; Meraz, Carlos Alberto; Mikos, Mary; Grande-Allen, K. Jane; BioengineeringFolder containing 3D-printable components of mesoscale testing deviceItem Tracking Demonstration Video of 1:10 PDMS from Mesoscale Testing Device on Fluorescence Microscope(Rice University, 2020) Mehta, Shail Maharshi; De Santos, Diego Ricardo; Sridhar, Shweta; Aguayo, Veronica Cristina; Meraz, Carlos Alberto; Mikos, Mary; Grande-Allen, K. Jane; BioengineeringEdge tracking output from testing video taken using a fluorescence microscope at 10x magnification of 1:15 PDMS. Yellow lines indicate tracking pathsItem Tracking Demonstration Video of 1:15 PDMS from Mesoscale Testing Device(Rice University, 2020) Mehta, Shail Maharshi; De Santos, Diego Ricardo; Sridhar, Shweta; Aguayo, Veronica Cristina; Meraz, Carlos Alberto; Mikos, Mary; Grande-Allen, K. Jane; BioengineeringPoint tracking output from testing video taken using a stereomicroscope at 0.63x magnification of 1:15 PDMS. Yellow lines indicate tracking paths. One red line directly connects the center points of the sample-attached and static element points. The other red line indicates where the sample-attached point would have been without the presence of a sample. The difference between the endpoints of these lines is the deflection, shown using blue lines