PIV and LIF Measurements in Aortic Dissection Models

Abstract

In this work an in-vitro flow experiment is conducted to elucidate the flow behavior in simplified aortic dissection (AD) disease geometries. In AD, the innermost layer of the aortic wall is locally and partially torn allowing blood to flow between the wall layers forming a parallel blood stream in what is known as the false lumen. The aim of this work is to elucidate the disease flow physics, and to provide guidance in diagnostic radiology, particularly contrast injected computed tomography (CT), where understanding flow patterns and mixing behavior is important for accurate diagnosis. In contrast-CT, dye is injected in the peripheral blood stream to illuminate the blood vessels and identify vascular abnormalities. The flow patterns and the dye transport dynamics impact the nature of the CT images and their interpretation. Particle image velocimetry (PIV) is used to quantify the AD flow fields, and laser-induced fluorescence (LIF) is implemented to visualize and assess the mixing behavior of dye in the false and true lumens. Interesting flow patterns are revealed and discussed in the context of their possible contribution to tear expansion and flapping, and to the elevated mean pressure in the false lumen that is reported in the literature.

A combined experimental and computational study of the flow characteristics in a Type B aortic dissection: Effect of primary and secondary tear size

“…Furthermore, Clough et al (2012) reported the presence of helical flows at different locations in the false lumen by examining images acquired with phasecontrast magnetic resonance imaging (PC-MRI) and related these helical flows to the aortic expansion rate. More recently, a few research groups are employing laser diagnostic methods to explore the haemodynamics in higher spatial and temporal resolution, using primarily particle image velocimetry (PIV) (Yip et al, 2004;Salameh et al, 2017Salameh et al, , 2019Moravia et al, 2019) and stereo-particle image velocimetry (s-PIV) (Fernandes et al, 2019).…”