X-ray Velocimetry and Haemodynamic Forces Within a Stenosed Femoral Model at Physiological Flow Rates

Abstract

High resolution in vivo velocity measurements within the cardiovascular system are essential for accurate calculation of vessel wall shear stress, a highly influential factor for the progression of arterial disease. Unfortunately, currently available techniques for in vivo imaging are unable to provide the temporal resolution required for velocity measurement at physiological flow rates. Advances in technology and improvements in imaging systems are allowing a relatively new technique, X-ray velocimetry, to become a viable tool for such measurements. This study investigates the haemodynamics of pulsatile blood flow in an optically opaque in vitro model at physiological flow rates using X-ray velocimetry. The in vitro model, an asymmetric stenosis, is designed as a 3:1 femoral artery with the diameter and flow rate replicating vasculature of a mouse. Velocity measurements are obtained over multiple cycles of the periodic flow at high temporal and spatial resolution (1 ms and 29 μm, respectively) allowing accurate measurement of the velocity gradients and calculation of the wall shear stress. This study clearly illustrates the capability of in vitro X-ray velocimetry, suggesting it as a possible measurement technique for future in vivo vascular wall shear stress measurement.

Analysis of Intra-Aneurysmal Flow for Cerebral Aneurysms with Cerebral Angiography

“…DSA has been used for flow quantification before, and it has been used by others for velocity measurement, [16][17][18] and aneurysmal flow evaluation. [9][10][11] These studies demonstrate that the change of signal does have a potential to assist us in understanding the hemodynamics in arteries and aneurysms.…”

Imaging regional lung function: A critical tool for developing inhaled antimicrobial therapies

“…By allowing the X-ray wave to propagate a large distance between the sample and detector, interference fringes are generated at the detector plane by the X-ray waves that are slightly refracted at the surface interfaces contained in the sample. The ability to image in phase contrast without gratings or other apparatus between the sample and detector provides a higher efficiency, and therefore increased capability for dynamic imaging [78,[87][88][89][90]. There have been a number of studies that utilize planar PBI for in vivo lung imaging, taking advantage of a simple implementation and capacity for dynamic imaging.…”

‘Go with the flow ’: A review of methods and advancements in blood flow imaging

“…means of in vivo wall shear stress measurement, as it is a highly influential factor for the progression of arterial disease [421].…”