Relation between plaque type, plaque thickness, blood shear stress, and plaque stress in coronary arteries assessed by X‐ray Angiography and Intravascular Ultrasound

Abstract

Purpose: Atheromatic plaque progression is affected, among others phenomena, by biomechanical, biochemical, and physiological factors. In this paper, the authors introduce a novel framework able to provide both morphological (vessel radius, plaque thickness, and type) and biomechanical (wall shear stress and Von Mises stress) indices of coronary arteries. Methods: First, the approach reconstructs the three-dimensional morphology of the vessel from intravascular ultrasound (IVUS) and Angiographic sequences, requiring minimal user interaction. Then, a computational pipeline allows to automatically assess fluid-dynamic and mechanical indices. Ten coronary arteries are analyzed illustrating the capabilities of the tool and confirming previous technical and clinical observations. Results: The relations between the arterial indices obtained by IVUS measurement and simulations have been quantitatively analyzed along the whole surface of the artery, extending the analysis of the coronary arteries shown in previous state of the art studies. Additionally, for the first time in the literature, the framework allows the computation of the membrane stresses using a simplified mechanical model of the arterial wall. Conclusions: Circumferentially (within a given frame), statistical analysis shows an inverse relation between the wall shear stress and the plaque thickness. At the global level (comparing a frame within the entire vessel), it is observed that heavy plaque accumulations are in general calcified and are located in the areas of the vessel having high wall shear stress. Finally, in their experiments the inverse proportionality between fluid and structural stresses is observed.

Standardized evaluation methodology and reference database for evaluating IVUS image segmentation

“…Such characteristics are essential for the clinical diagnosis since to date it is the only modality enabling the accurate morphological segmentation of both vessel membranes (lumen and media) and the assessment of the plaque type in vivo [5,6]. Additionally, when IVUS is fused with X-ray projections, three dimensional plaque quantification and reconstruction can be obtained [7,8] (Fig. 2).…”

3D reconstruction of coronary artery bifurcations from intravascular ultrasound and angiography

“…IVUS images have several anatomical features, including the lumen, external elastic membrane (EEM), and plaque materials. Several studies have proposed methods for combining IVUS and angiography images for 3D reconstruction of coronary arteries [5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23] ; however, these approaches were focused on non-bifurcated vessels. Some studies have performed 3D reconstruction of bifurcations but relied on computed tomography (CT) images to correct the IVUS frame orientation, limiting their clinical applicability 24,25 .…”

Thin-Cap Fibroatheroma Rupture Is Associated With a Fine Interplay of Shear and Wall Stress

“…All such studies of vessel wall mechanics use intravascular ultrasound (IVUS) combined with FEA to compute wall stress. For example, a comprehensive analysis was performed by Balocco et al, 30 which showed an inverse relationship between shear stress and wall stress in 10 patients with plaques, an observation that was recently confirmed by Fan et al 31 Liang et al 32 used a fluid-solid interaction model in diseased vessel segments of 4 patients and identified increasing stress concentrations with thinning of the cap, and the presence of microcalcifications, as observed previously. 33 Hence, these invasive studies confirmed observations from the noninvasive ones that local stress concentrations occur during plaque development.…”