Quantitative assessment of atherosclerotic lesion of rabbit aorta by compressed slice analysis of magnetic resonance images ex vivo

Abstract

The objective of the present study was to evaluate a new compressed slice analysis technique of aortas ex vivo. Atherosclerosis was developed in rabbits by feeding an atherogenic diet containing 2% cholesterol and 6% peanut oil for 8 weeks. At termination, aortas were excised and imaged ex vivo by Magnetic resonance images (MRI). MRI data were acquired on a super high magnetic field vertical bore imaging scanner equipped with a Unity/Inova console, operating at 14.1 T and dedicated to small animal studies. T2-weighted coronal 2-D sections were acquired first to determine a ROI (region of interest) of the thoracic aorta using a Spin-Echo multi slice pulse sequence. Then, T2-weighted images were acquired in transversal sections of ROI slice by slice (2 mm/slice) in the total length of 4 cm. The MRI images of 20 slices were then compressed into a single image, and the resultant compressed single image was used as a quantitative characteristic of atherosclerotic lesions. By utilizing the compressed slices (CS) analysis, the imaging intensity of atherosclerotic lesions was calculated. A significant correlation was found between the quantitative CS-MRI and the aortic cholesterol content (Pearson correlation coefficient r = 0.95). The present findings demonstrate that the compressed slice analysis technique of MRI images could be applied for a quantitative assessment of the progression and/or regression of atherosclerosis.