- PhD,
PhD Defense - Marco CASTAGNA - ED SPI
PhD Defense, Marco CASTAGNA : at 2 pm on Thursday 9 July by videoconference.
on July 9, 2020
PhD Defense, Marco CASTAGNA: at 2 pm on Thursday 9 July by videoconference.
Videoconference linkSupervisor: Jean-Michel SERFATY, Institut du Thorax
Laboratory: LHEAA
Abstract:
Atherosclerosis accounts for about 21% of deaths worldwide. It develops primarily in specific locations of the cardiovascular system where the Wall Shear Stress (WSS) can deviate more easily from its baseline values. Potential clinical applications of WSS as a biomarker rely on an accurate assessment of blood velocity in patients since it is defined from the derivative of blood velocity at the arterial wall. The present work aims to design and develop a hydraulic test rig to validate Phase Contrast Magnetic Resonance Imaging (PC MRI) velocity acquisitions and the computation of derived WSS. To do that, reference velocity profiles were obtained with Laser Doppler Velocimetry (LDV) and employed as a standard for direct comparison with PC MRI results. The experimental set-up was composed of an MRI compatible pump, flexible connection pipes, a test section, a reservoir, a working fluid, and a flowmeter. One standard 2D PC MRI and one standard 4D Flow MRI sequences were employed to obtain MRI velocity profiles, adjusting their parameters as in clinical practice. The WSS was calculated with the 2D and 3D methods proposed respectively by Stalder et al. and Potter et al. A second experimental campaign was performed with the refinement of the data spatial and temporal resolution, employing only the 4D Flow MRI sequence. Results indicated an excellent agreement between MRI and LDV velocity and WSS data. This study represents a reliable basis for any validation with LDV of 4D Flow MRI based methods for WSS calculation.
