Contrast-enhanced MRI of carotid atherosclerosis: dependence on contrast agent

Abstract

Purpose: To investigate the dependence of contrast-enhanced magnetic resonance imaging (MRI) of carotid artery atherosclerotic plaque on the use of gadobenate dimeglumine versus gadodiamide.

Materials and methods: Fifteen subjects with carotid atherosclerotic plaque were imaged with 0.1 mmol/kg of each agent. For arteries with interpretable images, the areas of the lumen, wall, and necrotic core and overlying fibrous cap (when present) were measured, as were the percent enhancement and contrast-to-noise ratio (CNR). A kinetic model was applied to dynamic imaging results to determine the fractional plasma volume, v(p), and contrast agent transfer constant, K(trans).

Results: For 12 subjects with interpretable images, the agent used did not significantly impact any area measurements or the presence or absence of necrotic core (P > 0.1 for all). However, the percent enhancement was greater for the fibrous cap (72% vs. 54%; P < 0.05) necrotic core (51% vs. 42%; P = 0.12), and lumen (42% vs. 63%; P < 0.05) when using gadobenate dimeglumine, although no apparent difference in CNR was found. Additionally, K(trans) was lower when using gadobenate dimeglumine (0.0846 min(-1) vs. 0.101 min(-1); P < 0.01), although v(p) showed no difference (9.5% vs. 10.1%; P = 0.39).

Conclusion: Plaque morphology measurements are similar with either contrast agent, but quantitative enhancement characteristics, such as percent enhancement and K(trans), differ.

(c) 2009 Wiley-Liss, Inc.

Figures

Figure 1

Similarity of carotid plaque enhancement using gadodiamide (a,b) versus gadobenate dimeglumine (c,d). T1-weighted MR images are shown before (a,c) and after (b,d) injection of 0.1 mmol/kg of the corresponding agent. Each pair shows the images with and without contours corresponding to the lumen (red) outer wall boundary (light blue), necrotic core (yellow) and inner and outer fibrous cap boundaries (green).

Figure 2

Percent enhancement characteristics by atherosclerotic plaque tissue type show greater enhancement (*p

Figure 3

Kinetic modeling of contrast agent dynamics in carotid atherosclerosis exhibits similar results for gadodiamide (a) versus gadobenate dimeglumine (b). MR images show T1-weighted reference image (left), parametric image of partial plasma volume vp (middle), and parametric image of the transfer constant Ktrans (right). Asterisks indicate the carotid artery lumen and arrows indicate a rim of high Ktrans corresponding to the outer wall boundary.