Diagnostic Value of Magnetic Resonance Imaging in Evaluating Carotid Artery Atherosclerotic Plaque Morphology

Abstract

Magnetic Resonance Imaging has the ability to describe vessel wall thickness, plaque structure, distinguish fibrotic, fatty, calcific or hemorrhagic plaque contents with excellent soft tissue contrast. Our aim in this study is to determine symptomatic and asymptomatic carotid plaque morphology and imaging properties. We tried to understand whether plaque components in images match with histopathological sections. MRI was performed in 37 patients known to have carotid stenosis and endarterectomy decision has been taken. 24 patients were symptomatic and 13 were asymptomatic for carotid disease. A surface coil used in MRI; 5 cm of carotid segment was imaged with the carotid bifurcation in the middle. Necrotic core, fibrous cap, hemorrhage, calcification and intraluminal thrombus were determined in MR images. After surgery, the specimens were evaluated by a pathologist who was blind to the radiological findings. All plaque contents (necrotic core, hemorrhage, calcification and fibrous cap) can be imaged and separated from each-other with MRI. Necrotic core was detected in 87.9% of patients on MR images. No significant difference was found between symptomatic and asymptomatic cases in terms of the rate and dimensions of necrotic core on MRI. The presence of calcification did not show a significant difference between symptomatic and asymptomatic cases. The sensitivity of MRI in detecting in-plaque hemorrhage was calculated as 82.3% and specificity as 68.75%. The calculated rates were interpreted as MRI is significant in distinguishing cases without bleeding. Fibrous cap was more preserved in asymptomatic patients. The structure of the atheroma plaque can be imaged and distinguished from each other with MRI. The statistical results did not show the expected performance mainly due to the small number of asymptomatic cases, which was the main limitation of the study.