High-resolution magnetic resonance imaging using gadolinium-based contrast agent for atherosclerotic carotid plaque

Early detection of vulnerable plaques at risk of causing thromboembolic events is very important, and many investigators report the usefulness of high-resolution MRI. The purpose of this study was to determine whether the detection of atherosclerotic carotid plaques can be enhanced after administration of contrast agents and, if so, to evaluate the potential for functional information.

We studied 9 patients (10 subjects) who underwent a high-resolution MRI examination using a gadolinium-based contrast agent before CEA. Pre- and postcontrast-enhanced T1-weighted images were reviewed, and their histopathologic characteristics evaluated in the corresponding tissue slices.

Strong contrast enhancement patterns were found in 6 of 10 subjects. For 5 of 6 subjects, many microvessels with inflammatory cells or intraplaque hemorrhages were demonstrated in their corresponding tissue slices. Contrast enhancement patterns were noted to be focal, diffuse, and along the luminal surface or the vessel adventitial boundary. Moreover, some plaques were clearly demonstrated by using contrast agent, and others were clearly divided into fibrous and lipid regions.

Gadolinium-based contrast agent can penetrate human atherosclerotic carotid plaques. The extent or size of neovascularization and the endothelial permeability are likely related to the mechanism of enhancement, and contrast-enhanced MRI may be essential for the identification of plaque neovascularization which is an important factor of vulnerable plaques. In addition to morphologic information, with the functional information provided using various contrast agents, we may expect a more correct diagnosis of carotid plaques at risk of causing thromboembolic events.