Measuring Mouse Abdominal Aorta Dimensions In Vivo: A Comparison Between (3d) Ultrasound And Micro-Ct


Authored by  B Trachet*, P Segers*, F Claes*, A Berges

Presented at 6TH WORLD CONGRESS ON BIOMECHANICS     
* This author is not affiliated with PMI.

Abstract

Introduction: Mouse models are very useful to study the origin and progression of cardiovascular diseases. An important component of the follow-up process, however, involves in vivo imaging of cardiovascular structures. Recently, this has become possible due to the introduction of high-frequency ultrasound (US) technology and specific contrast agents for micro-ct. In order to test the comparability of these imaging modalities, we compared abdominal aortic (AA) diameter values measured in 9 mice at 4 different time points using 3 in vivo methods: in vivo micro-CT, 3D US, and M-mode US. Methods: Nine Apolipoprotein E-deficient mice (7-weeks-old) were scanned after 0, 8, 12, and 19 days. At each time point, m-mode measurements were taken using Vevo770 equipment (Visualsonics) to assess the AA diameter at the proximal, middle, and distal zone (marked by the branching of celiac and left renal arteries, respectively, with each zone having an average length of about 5 mm). A 3D reconstruction was performed using transversal b-mode images of the AA over a range of 2 cm. Subsequently, the animals were IV. Injected with 0.0075 ml/g Exia 160 XL (Binitio) and scanned in a micro-CT (Skyscan 1076). The contrast allowed us to discriminate the aorta from the surrounding tissues. For each AA zone, diastolic and systolic diameters were measured and the average diameter was calculated. The b-mode images were segmented using the edge detection algorithm of the us software, and the micro-CT images were manually segmented in mimics. For both 3d geometries, an average value of the AA diameter was calculated for each zone. Statistical comparison (Univariate analysis of variance or paired samples t-test) was performed using the software package SPSS. Results and discussion: all AA diameters increased significantly over time.