Critical Stenosis of the Internal Carotid Artery: Variability in Vertebral Artery Diameters and Areas of Cerebral Chronic Infarction in Computed Tomography.

OBJECTIVES: We investigated unilateral and bilateral cervical internal carotid artery (ICA) stenosis according to the North American Symptomatic Carotid Endarterectomy Trial (NASCET) and the European Carotid Surgery Trial (ECST).

METHODS: We retrospectively investigated ICA stenosis on Head&Neck Computed Tomography Angiography (CTA); and their simultaneous brain computed tomography images were also evaluated. In unilateral ICA stenosis group (n=36), 17 of them had right ICA stenosis and 19 left ICA stenosis. In bilateral stenosis group, there were 24 patients. ICA stenosis was evaluated according to NASCET and ECST methods. We also evaluated vertebral artery dimension, plaque density and cerebral infarct (Cerebral kortex, white matter, basal ganglion-thalamus).

RESULTS: Unilateral ICA stenosis according to the NASCET was 70.64% to 73.68% (right-left) and according to the ECTS was 65.52% to 71.15% (right-left). For bilateral stenosis, ICA stenosis according to the NASCET was 67.70 to 67.91 (right-left); according to the ECTS was 62.45% to 62.15% (right-left). Vertebral artery dimensions were 3.26 to 3.72 mm (right-left) in unilateral ICA stenosis; and 3.52 to 3.71 mm (right-left) in bilateral ICA stenosis. In bilateral stenosis group, mixt plaque; and in unilateral stenosis group, hard plaque was detected. In unilateral stenosis, white matter and basal ganglion-thalamus infarcts; in bilateral ICA stenosis, cerebral cortical infarct was detected. Left-vertebral artery diameter increased in higher L-ECTS ICA stenosis (unilateral) group.

CONCLUSION: Increase in left vertebral artery diameter in unilateral L-ECTS ICA stenosis may be related to increase of the collateral flow by vertebral arteries to support brain blood-flow.