Arterial Wall Imaging in Symptomatic Carotid Stenosis: Delayed Enhancement on MDCT Angiography

OBJECTIVE To evaluate progressive enhancement in the carotid arterial wall overlying plaque in the symptomatic side for patients with cerebrovascular symptoms until delayed phase using MDCTA. MATERIALS AND METHODS Twenty-one patients (all men; ages, 49-82 years; mean, 67.8 ± 8.4 years) with recent stroke and severe extracranial carotid stenosis were retrospectively analyzed. Pre-, early- and delayed phase images of MDCTA were obtained, and Hounsfield units (HU) of carotid walls were measured. We also measured HU of the asymptomatic contralateral carotid arterial wall for comparison. Friedman's test and Wilcoxon signed-rank test were used to evaluate the differences between groups. RESULTS The averaged HU of the carotid wall in the symptomatic side was higher on the delayed phase (65.8 ± 14.2 HU) compared to early arterial phase (54.2 ± 12.6 HU). The averaged HU difference of wall enhancement between pre-contrast and delayed phase (28.0 ± 14.8 HU) was significantly higher than the between pre-contrast and early arterial phase (16.4 ± 12.1 HU) with P < 0.05. In analysis of the contralateral asymptomatic side, the HU difference between pre-contrast and delayed phase (15.5 ± 12.0 HU) showed no significant higher value than between pre-contrast and early arterial phase (14.9 ± 10.9 HU). CONCLUSION The pronounced enhancement of the carotid wall in the delayed phase on MDCTA was demonstrated in symptomatic patients with severe internal carotid artery stenosis. In the future, we need more comparative studies to verify this finding as one of risk stratification.