Regional Mapping of Aortic Wall Stress by Using Deformable, Motion-coherent Modeling based on Electrocardiography-gated Multidetector CT Angiography: Feasibility Study

Abstract

Purpose To investigate the feasibility of deformable, motion-coherent modeling based on electrocardiography-gated multidetector computed tomographic (CT) angiography of the thoracic aorta and to evaluate whether quantifiable information on aortic wall stress as a function of patient-specific cardiovascular parameters can be gained. Materials and Methods For this institutional review board-approved, HIPAA-compliant study, thoracic electrocardiography-gated dual-source multidetector CT angiographic images were used from 250 prospectively enrolled patients (150 men, 100 women; mean age, 79 years). On reconstructed 50-phase CT angiographic images, aortic strain and deformation were determined at seven cardiac and aortic locations. One-way analysis of variance was used by assessing the magnitude for longitudinal and axial strain and axial deformation, as well as time-resolved peak and maxima count for longitudinal strain and axial deformation. Interdependencies between aortic strain and deformation with extracted hemodynamic parameters were evaluated. Results With increasing heart rates, there was a significant decrease in longitudinal strain (P = .009, R(2) = 0.95) and a decrease in the number of longitudinal strain peaks (P < .001, R(2) = 0.79); however, a significant increase in axial deformation (P < .001, R(2) = 0.31) and axial strain (P = .009, R(2) = 0.61) was observed. Increasing aortic blood velocity led to increased longitudinal strain (P = .018, R(2) = 0.42) and longitudinal strain peak counts (P = .011, R(2) = 0.48). Pronounced motion in the longitudinal direction limited motion in the axial plane (P < .019, R(2) = 0.29-0.31). Conclusion The results of this study render a clinical basis and provide proof of principle for the use of deformable, motion-coherent modeling to provide quantitative information on physiological motion of the aorta under various hemodynamic circumstances. (©) RSNA, 2016 Online supplemental material is available for this article.

Three-dimensional thoracic aorta principal strain analysis from routine ECG-gated computerized tomography: feasibility in patients undergoing transcatheter aortic valve replacement

“…This study demonstrates the clinical feasibility and reproducibility of 3D thoracic aorta wall principal strain mapping using routine ECG-gated CTA. Assessments of global and regional aortic biomechanics showed significantly greater strain impairment with worsening hemodynamic measures of AS severity, consistent with findings demonstrated previously by 2D aortic strain techniques [ 12 , 29 ]. Accordingly, this study establishes the potential of routine ECG-gated CTA to provide reproducible measures of 3D global and regional aortic tissue health, and seeds interest for exploring such post-processing techniques across a broad range of patients with aortic disease currently evaluated by CTA.…”

“…Our study found highly significant correlations between lower 3D thoracic aorta PPSA and worsening measures of AS severity. These findings suggest that the presence of severe AS has a dominant influence on aortic deformation and remodeling that may significantly outweigh concurrent physiologic factors, a relationship that has also been described in prior reports [ 7 , 12 , 36 ].…”

“…Expanding interest in the study of ECG-gated CTA for the evaluation of vascular deformation is related to its full anatomic coverage of the thoracic aorta coupled with its superior spatial resolution, providing a dynamic isotropic dataset appropriate for quantitative biomechanical assessments [ 12 ]. Previous studies have used CTA to calculate circumferential and longitudinal 2D thoracic aorta strain based upon differences in vessel caliber throughout the cardiac cycle [ 10 , 11 , 15 , 37 ].…”

“…With complete 3-dimensional (3D) visualization at high isotropic spatial resolution, small displacements of the aortic wall can be resolved throughout the complex architecture. Multi-phase reconstruction of such imaging has previously been used to derive 2-dimensional (2D) strain, [ 10 – 12 ]. A methodology exists to perform in-vivo 3D aortic strain analysis requiring a single segmentation at end-diastole, optically and automatically tracked in 3 dimensions throughout the cardiac cycle relying on a velocity-field reconstructed for the whole dataset by means image-based feature tracking, described by Satriano et al [ 13 ].…”

Visit to intensive care of 2050

“…For example, since heart disease remains a major determinant of life expectancy, most general ICUs have integrated cardiology services. Patients presenting with an acute cardiac event are evaluated by utilizing bedside computerized tomography, which provides not only structural but also physiological/ functional data [23,24]. These data are exported into a nanotechnology interventional system that performs cardiac procedures when required (e.g.…”