Volume 16 Supplement 1
Rapid 4D regional wall motion characterization of abdominal aortic aneurysms with intra-luminal thrombus using cine cardiac MRI
© Menon et al.; licensee BioMed Central Ltd. 2014
Published: 16 January 2014
The clinical assessment of abdominal aortic aneurysm (AAA) rupture risk is largely limited to quantification of maximum diameter over time to monitor growth. Recent studies have extended this paradigm to modeling biomechanical loading and wall stresses using computational hemodynamics or solid mechanics simulations, in efforts to reliably numerically predict aneurysm-specific wall motion. However, the numerical simulation of aneurysm wall motion is time and resource intensive, and inherently involves complex mathematical modeling of often unrealistic wall properties. In this study, we characterize AAA wall motion using shape-analysis to quantify detailed regional function by direct processing of 4D (3D + time) cine CMR data.
Inner blood-contacting endothelial wall (excluding thrombus) function in 13 AAAs was studied using a shape-derived metric of wall velocity defined by a signed phase-to-phase Hausdorff distance (HD) computed at uniformly spaced points tracked on surface contours segmented from CMR images, over the cardiac cycle, using an in-house software. HD colormaps were superimposed upon the AAA inner wall at the diastolic phase to visualize regional wall motion. A endothelial wall velocity (EWV: displacement in mm per phase) was estimated to be a function of phase-to-phase displacement time-histories at tracked points. Additionally, outer wall segmentations were also prepared and compared with the inner wall at each cardiac phase to quantify radial wall thickness and signed wall-thickening (diastole to systole) using an open-souce cardiac MRI suite, Medviso Segment. This was compared with the observed EWV from HD analysis for validation purposes.
We present a simple and effective means to directly quantify AAA wall motion from CMR data, without the need for numerical simulation. EWV extracted from the presented analyses may be extended to the prediction of aneurysm wall stresses and strain, which may in-turn constitute a promising paradigm for evaluating AAA rupture risk.
This study was possible through the Open Field Entrepreneur's Fund award to QuantMD, LLC.
This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.