gadofluorine-m and Aortic-Diseases

Inflammation and neovascularization play critical roles in the stability of atherosclerotic plaques. Whole-body quantitative assessment of these plaque features may improve patient risk-stratification for life-threatening thromboembolic events and direct appropriate intervention. In this report, we determined the utility of the MR contrast agent gadofluorine-M (GdF) for staging plaque stability and compared this to the conventional agent Gd-DTPA.. Five control and 7 atherosclerotic rabbits were sequentially imaged after administration of Gd-DTPA (0.2 mmol/kg) and GdF (0.1 mmol/kg) using a T(1)-weighted pulse sequence on a 3-T MRI scanner. Diseased aortic wall could be distinguished from normal wall based on wall-to-muscle contrast-to-noise values after GdF administration. RAM-11 (macrophages) and CD-31 (endothelial cells) immunostaining of MR-matched histological sections revealed that GdF accumulation was related to the degree of inflammation at the surface of plaques and the extent of core neovascularization. Importantly, an MR measure of GdF accumulation at both 1 and 24 hours after injection but not Gd-DTPA at peak enhancement was shown to correlate with a quantitative histological morphology index related to these 2 plaque features.. GdF-enhanced MRI of atherosclerotic plaques allows noninvasive quantitative information about plaque composition to be acquired at multiple time points after injection (within 1 and up to 24 hours after injection). This dramatically widens the imaging window for assessing plaque stability that is currently attainable with clinically approved MR agents, therefore opening the possibility of whole-body (including coronary) detection of unstable plaques in the future and potentially improved mitigation of cataclysmic cardiovascular events.

Topics: Animals; Aortic Diseases; Aortic Rupture; Atherosclerosis; Contrast Media; Disease Models, Animal; Feasibility Studies; Fluorocarbons; Gadolinium DTPA; Injections; Magnetic Resonance Angiography; Male; Organometallic Compounds; Predictive Value of Tests; Rabbits

Inflammation and neovascularization may play a significant role in atherosclerotic plaque progression and rupture. We evaluated gadofluorine-M-enhanced MRI for detection of plaque inflammation and neovascularization in an animal model of atherosclerosis.. Sixteen rabbits with aortic plaque and 6 normal control rabbits underwent gadofluorine-M-enhanced MRI. Eight rabbits had advanced atherosclerotic lesions, whereas the remaining 8 had early lesions. Magnetic resonance atherosclerotic plaque enhancement was meticulously compared with plaque inflammation and neovessel density as assessed by histopathology. Advanced plaques and early atheroma were enhanced after gadofluorine-M injection. Control animals displayed no enhancement. After accounting for the within-animal correlation of observations, mean contrast-to-noise ratio was significantly higher in advanced plaques than compared with early atheroma (4.29+/-0.21 versus 3.00+/-0.32; P=0.004). Macrophage density was higher in advanced plaques in comparison to early atheroma (geometric mean=0.50 [95% CI, 0.19 to 1.03] versus 0.25 [0.07 to 0.42]; P=0.05). Furthermore, higher neovessel density was observed in advanced plaques (1.83 [95% CI, 1.51 to 2.21] versus 1.29 [0.99 to 1.69]; P=0.05). The plaque accumulation of gadofluorine-M correlated with increased neovessel density as shown by linear regression analysis (r=0.67; P<0.001). Confocal and fluorescence microscopy revealed colocalization of gadofluorine-M with plaque areas containing a high density of neovessels.. Gadofluorine-M-enhanced MRI is effective for in vivo detection of atherosclerotic plaque inflammation and neovascularization in an animal model of atherosclerosis. These findings suggest that gadofluorine-M enhancement reflects the presence of high-risk plaque features believed to be associated with plaque rupture. Gadofluorine-M plaque enhancement may therefore provide functional assessment of atherosclerotic plaque in vivo.

Topics: Animals; Aorta; Aortic Diseases; Atherosclerosis; Contrast Media; Disease Models, Animal; Feasibility Studies; Fluorocarbons; Inflammation; Linear Models; Lipid Metabolism; Macrophages; Magnetic Resonance Angiography; Microscopy, Confocal; Microscopy, Fluorescence; Neovascularization, Pathologic; Organometallic Compounds; Predictive Value of Tests; Rabbits; Reproducibility of Results; Rupture