Computed tomography of the cervical carotid artery: significance of the lucent defect.

To investigate the clinical significance of lucent defects in computed tomography (CT) scans of the cervical carotid artery plaque, we studied 95 patients with recent symptoms of hemispheric ischemia. Using multiple linear regression analysis, we estimated the strength of the association of symptoms with laterality of carotid artery lucent lesions, stenoses, and ulcerations observed in CT scans. Hemispheric symptoms correlated strongly with ipsilateral carotid lucent lesions (partial p less than 0.025) and with ipsilateral severe (greater than 75%) carotid stenosis (partial p less than 0.025). Carotid artery ulcerations had a weaker association (partial p less than 0.1), and stenoses of mild and moderate degrees showed none. The overall performance of all three plaque complications was highly significant (p less than 0.005). The lucent defect indicates a morphologic change in the carotid plaque that plays an important role in the development of symptoms of hemispheric ischemia. This is in agreement with the notion that the lucent defect is the image of intraplaque hemorrhage and/or necrosis, which are complications central to the development of symptomatic carotid disease.