Lipid-Rich Atherosclerotic Plaques Detected by Gadofluorine-Enhanced In Vivo Magnetic Resonance Imaging

Abstract

Background-MRI of specific components in atherosclerotic plaque may provide information on plaque stability and its potential to rupture. We evaluated gadofluorine in atherosclerotic rabbits using a new MR sequence that allows plaque detection within 1 hour after injection and assessed enhancement in lipid-rich and non-lipid-rich plaques. Methods and Results-Twelve rabbits with aortic plaque and 6 controls underwent MRI before and up to 24 hours after gadofluorine injection (50 mol/kg). Two T1-weighted, segmented gradient-echo sequences (TFL) were compared to enhance vessel wall delineation after injection: (1) an inversion-recovery prepulse (IR-TFL) or (2) a combination of inversion-recovery and diffusion-based flow suppression prepulses (IR-DIFF-TFL). With the use of IR-TFL at 1 hour after injection, the vessel wall was not delineated because of poor flow suppression; at 24 hours after injection, the enhancement was 37% (PϽ0.01). IR-DIFF-TFL showed significant enhancement after versus before contrast (1 . There was no enhancement in the vessel wall after gadofluorine injection in the control group. A strong correlation was found (r 2 ϭ0.87; PϽ0.001) between the lipid-rich areas in histological sections and signal intensity in corresponding MR images. This suggests a high affinity of gadofluorine for lipid-rich plaques. Conclusions-Gadofluorine-enhanced MRI improves atherosclerotic plaque detection. The IR-DIFF-TFL method allows early detection of atherosclerotic plaque within 1 hour after gadofluorine injection.

Magnetic resonance imaging of experimental atherosclerotic plaque: Comparison of two ultrasmall superparamagnetic particles of iron oxide

“…Intravenous injection of these dyes causes increased signal intensity of blood and tissue on T1-weighted MR images in atherosclerotic lesions. While the use of such agents, e.g., gadofluorine, initially would have mandated a considerable time interval between the injection and the MR examination in order to achieve gadolinium accumulation in the plaque and washout from the blood-pool (17), most recent technical refinements allow for plaque detection as soon as one hour after contrast administration (18). However, to date these agents have not been evaluated in humans, whereas ferumoxtran-10 has almost completed phase 3 clinical testing.…”

Evaluation of neovessels in atherosclerotic plaques of rabbits using an albumin‐binding intravascular contrast agent and MRI

“…Hence, the discrimination between atherosclerotic plaques and lumen is hampered by a persistent short T1 in blood. Even though dedicated MR acquisitions have been developed to null the luminal signal, the best time point for atherosclerotic plaque detection was estimated only at 24 h after injection (16).…”

Molecular Imaging in Cardiovascular Diseases

“…This is a gadolinium-based macrocyclic molecular probe with both hydrophilic and hydrophobic characteristics as well as a blood half-life comparable to conventional gadolinium chelates [45]. Heavy accumulation of gadofluorine in lipid-rich plaques was exhibited in a rabbit model with atherosclerosis [46]. Furthermore, recent publications have described co-localization of this molecular probe in regions with a high density of newly-formed vessels (a characteristic of vulnerable plaque) as well as collagen-rich (fibrous) plaque regions [47,48].…”