Real-time assessment of flow reversal in an eccentric arterial stenotic model

Abstract

Plaque rupture is the leading cause of acute coronary syndromes and stroke. Plaque formation, or otherwise known as stenosis, preferentially occurs in the regions of arterial bifurcation or curvatures. To date, real-time assessment of stenosis-induced flow reversal remains a clinical challenge. By interfacing Micro-electro-mechanical Systems (MEMS) thermal sensors with the high frequency Pulsed Wave (PW) Doppler ultrasound, we proposed to assess flow reversal in the presence of an eccentric stenosis. We developed a 3-D stenotic model (inner diameter of 6 mm, an eccentric stenosis with a height of 2.75mm and width of 21 mm) simulating a superficial arterial vessel. We demonstrated that heat transfer from the sensing element (2 × 80 μm) to the flow field peaked as a function of flow rates at the throat of the stenosis alone the center/midline of arterial model, and dropped downstream from the stenosis where flow reversal was detected by the high frequency ultrasound device at 45 MHz. Computational fluid dynamics (CFD) codes were in agreement with the ultrasound-acquired flow profiles upstream, downstream, and at the throat of the stenosis. Hence, we characterized regions of eccentric stenosis in terms of changes in heat transfer alone the midline of vessel and identified points of flow reversal with high spatial and temporal resolution.

Micromachined Thermal Flow Sensors—A Review

“…The sensor was packaged to an electrically conductive catheter and inserted into the arterial walls of live rabbits where dynamic pulsatile blood flow was measured. Rabbit blood was used for benchtop characterization of the sensor through a PDMS flow channel before in vivo implantation [69][70][71][72][73][74][75]. …”

Blood flow modulation of vascular dynamics

“…Given the limitations in real-time prediction of rupture-prone regions, Ai et al demonstrated flow reversal in a 3-D eccentric stenotic model by high frequency ultrasonic transducer (45 MHz) [14]. By interfacing microelectromechanical system (MEMS) thermal sensors with the high-frequency pulsed wave Doppler ultrasound, real-time assessment of changes in fluid shear stress upstream, downstream, and at the throat of the stenosis was validated by both computational fluid dynamics (CFD) codes and the ultrasound-acquired flow profiles.…”

“…By interfacing microelectromechanical system (MEMS) thermal sensors with the high-frequency pulsed wave Doppler ultrasound, real-time assessment of changes in fluid shear stress upstream, downstream, and at the throat of the stenosis was validated by both computational fluid dynamics (CFD) codes and the ultrasound-acquired flow profiles. Furthermore, post-stenotic regions are prone to vascular oxidative stress and inflammatory responses, features of clinical relevance [14]. In this context, the advent of micro shear stress sensors holds promise to identify vascular regions of flow reversal with high spatial and temporal resolution [15-17].…”

Analysis of measurement accuracy of air flow sensor influenced by moisture

“…In order to measure the flow rate of air, many types of flow sensor based on different principles are developed [1]. At present, Vane-type air flow meter, Karman-vortex air flow meter, Coriolis flow meter and hot film air flow sensor are the main four types of air flow sensor.…”