Detection of atherosclerotic plaque with gadofluorine-enhanced magnetic resonance imaging

Background - The purpose of this study was to visualize atherosclerotic plaques independently of luminal narrowing using T₁-weighted contrast-enhanced MRI. Methods and Results - Eight Watanabe heritable hyperlipidemic (WHHL) rabbits, aged 9 to 18 months, and 8 age-matched controls (New Zealand White rabbits) underwent MRI of the aortic arch before and up to 48 hours after injection of 100 μmol/kg Gadofluorine (Schering AG). Additionally, 8 WHHL rabbits were examined with Magnevist (Schering AG). A half-Fourier acquisition single-shot turbo-spin-echo (HASTE) sequence and a T₁-weighted inversion-recovery turbo fast, low-angle shot sequence were used for data acquisition. Immediately after the MR examination, the animals were killed, the aorta was stained with Sudan red, and ex vivo imaging of the stained aortic specimens was performed. Additionally, gadolinium concentrations in plaque (Sudan-positive) and normal (Sudan-negative) aortic wall segments were measured. Plain MR imaging revealed no plaques in the aortic arch in either animal group. Enhancement occurred in the aortic wall of all WHHL rabbits examined with Gadofluorine but not in the vessel wall of animals examined with Magnevist and the control group. Sudan red staining demonstrated multiple plaques in the aortic arch of all WHHL rabbits. Ex vivo imaging demonstrated that the area of hyperenhancement matched the area of plaques stained with Sudan red. The gadolinium concentration was 7±5 nmol/g for normal aortic wall of the control group and 368±30 nmol/g for aortic wall with plaque in WHHL. Conclusions - Gadofluorine enhances the imaging of atherosclerotic plaques and enables improved plaque detection of even nonstenotic lesions that are not visible on unenhanced MRI.