High-Frequency Three-Dimensional Lumen Volume Ultrasound Is a Sensitive Method to Detect Early Aneurysmal Change in Elastase-Induced Murine Abdominal Aortic Aneurysm

Abstract

Objective The aim of this study was to investigate the reproducibility of anterior–posterior diameter (APdmax) and three-dimensional lumen volume (3DLV) measurements of abdominal aortic aneurysms (AAA) in a classical murine AAA model. We also compared the magnitude of change in the aortic size detected with each method of assessment. Methods Periadventitial application of porcine pancreatic elastase (PPE AAA) or sham surgery was performed in two cohorts of mice. Cohort 1 was used to assess for observer variability with the APdmax and 3DLV measurements. Cohort 2 highlighted the relationship between APdmax and 3DLV and changes in AAA detected. Results There was no significant observer variability detected with APdmax measurement. Similarly, no significant intraobserver variability was evident with 3DLV; however, a small but significant interobserver difference was present. APdmax and 3DLV measurements of PPE AAA significantly correlated. However, changes in the AAA morphology were detected earlier with 3DLV. Conclusion APdmax and 3DLV are both reliable methods for measuring an AAA. Both these methods correlate with each other. However, changes in AAA morphology were detected earlier with 3DLV, which is important to detect subtle but important changes to aortic geometry in a laboratory setting. 3DLV measurement of AAA is a simple, reproducible, and comprehensive method for assessing changes in disease morphology.

Imaging Techniques for Aortic Aneurysms and Dissections in Mice: Comparisons of Ex Vivo, In Situ, and Ultrasound Approaches

“…High-frequency ultrasound is a powerful tool to monitor aortic diameters sequentially in living mice ( Figure 2 C) [ 14 , 107 , 108 ]. Therefore, ultrasonography has been used widely in mouse AAD studies.…”

“…Although specific units are required, several ultrasound systems can visualize mouse aortas in 3D [ 114 , 115 , 116 ]. Three-dimensional imaging enables the evaluation of aortic geometry more precisely, and 3D volumetric measurements can detect aortic dilatations at the earlier time point during AAA formation compared to 2D measurements [ 108 ]. Aortic imaging in 3D alleviates many issues associated with probe position and operator dependence.…”

3D Ultrasound Measurements Are Highly Sensitive to Monitor Formation and Progression of Abdominal Aortic Aneurysms in Mouse Models

“…The mode most commonly used is B-mode or brightness-mode, in which 2D cross-sectional images are acquired. Waduud et al have described the method of using 3D ultrasound for the evaluation of AAA development in the murine ePPE model ( 20 ). With the help of an automatic motor and an MS-550D probe at 40 MHz frequency, transverse imaging was performed and the 3D volume was calculated from 157 serial images recorded along a 12 mm abdominal aortic segment.…”

“…We thus hypothesized that a sensitive imaging method as developed by Waduud et al ( 20 ) may be suited to detect AAA formation at early time points in small-animal models and monitor their further development. This would offer the possibility to preferably test novel treatments on formed aneurysms and thus address the clinical demand to limit progression of established disease.…”

“…This would offer the possibility to preferably test novel treatments on formed aneurysms and thus address the clinical demand to limit progression of established disease. While Waduud et al ( 20 ) focused on the ePPE model as proof-of-principle, this study thus aimed to,…”