Ultrasound Time-Harmonic Elastography of the Aorta

Abstract

Objectives: The aim of this study was to investigate ultrasound time-harmonic elastography for quantifying aortic stiffness in vivo in the context of aging and arterial hypertension. Materials and Methods: Seventy-four participants (50 healthy participants and 24 participants with long-standing hypertension) were prospectively included between January 2018 and October 2018, and underwent ultrasound time-harmonic elastography of the upper abdominal aorta. Compound maps of shear-wave speed (SWS) as a surrogate of tissue stiffness were generated from multifrequency wave fields covering the full field-of-view of B-mode ultrasound. Blood pressure and pulse wave velocity were measured beforehand. Interobserver and intraobserver agreement was determined in 30 subjects. Reproducibility of time-harmonic elastography was assessed in subgroups with repeated measurements after 20 minutes and after 6 months. Linear regression analysis, with subsequent age adjustment of SWS obtained, receiver operating characteristic analysis, and intraclass correlation coefficients (ICCs) were used for statistical evaluation. Results: Linear regression analysis revealed a significant effect of age on SWS with an increase by 0.024 m/s per year (P < 0.001). Age-adjusted SWS was significantly greater in hypertensives (0.24 m/s; interquartile range [IQR], 0.17-0.40 m/s) than in healthy participants (0.07 m/s; IQR, −0.01 to 0.06 m/s; P < 0.001). A cutoff value of 0.15 m/s was found to differentiate best between groups (area under the receiver operating characteristic curve, 0.966; 95% confidence interval, 0.93-1.0; P < 0.001; 83% sensitivity and 98% specificity). Interobserver and intraobserver variability was excellent (ICC, 0.987 and 0.937, respectively). Reproducibility was excellent in the short term (ICC, 0.968; confidence interval, 0.878-0.992) and good in the long term (ICC, 0.844; confidence interval, 0.491-0.959). Conclusions: Ultrasound time-harmonic elastography of the upper abdominal aorta allows quantification of aortic wall stiffness in vivo and shows significantly higher values in patients with arterial hypertension.

Magnetic resonance elastography for estimating in vivo stiffness of the abdominal aorta using cardiac‐gated spin‐echo echo‐planar imaging: a feasibility study

“…Performing time-harmonic elastography in the aorta in healthy subjects, patients and animal models, Schaafs et al reported no significant correlation between aortic stiffness indicated by shear wave speed and diameter as well as wall thickness, suggesting the possibility of using effective aortic stiffness in clinical applications. 56,57 Similar to their findings, our previous study has reported an association between the aortic stiffness obtained with and without incorporating the thickness of the wall. 20 F I G U R E 9 A, PD SNR of FB SE-EPI and FB GRE on Scanner 1.…”

Characterization of Ascending Aortic Flow in Patients With Degenerative Aneurysms

“…Mechano-sensing of WSS and other mechanical stresses in the arterial wall are of great importance 34 . The exact influence of aberrant flow and deviated WSS on mechanotransduction deserves further evaluation, considering a previously described association of aortic stiffness with aortic disease progression 35 : an interesting goal for future studies would thus be to evaluate MR methods that combine flow analysis and markers of vessel wall stiffness such as pulse wave velocity and MR elastography 36–38 …”

Liquid-Liver Phantom

“…M easurement of tissue stiffness has been proven to be an accurate diagnostic marker for various diseases. [1][2][3][4][5][6][7][8] Especially, liver stiffness is an established imaging marker for hepatic diseases. [9][10][11] Liver stiffness is an intrinsic material property and can be quantified in vivo by elastography 12 and ex vivo by standardized reference methods such as shear rheomtery.…”

“…Measurement of tissue stiffness has been proven to be an accurate diagnostic marker for various diseases 1–8 . Especially, liver stiffness is an established imaging marker for hepatic diseases 9–11 .…”