Study on 16-section spiral CT angiography in the evaluation of carotid artery stenosis and comparison with imaging diagnosis

Objective To evaluate the accuracy and application of 16-section spiral CT angiography in the diagnosis of extracrania carotid artery stenosis. Methods Forty-nine patients with carotid artery stenosis or occlusion were diagnosed by Doppler ultrasonography (DUS), then CT angiography (CTA) and cerebral digital subtraction angiography (DSA) were performed. CTA of carotid artery were performed with contrast-medium dosage of 60-100 ml and injection rate of 3.5-4.0 ml/s. CTA images included original transverse images and multiplanar reformation (MPR), maximum intensity projection (MIP), volume rendering technique (VRT) and CT virtual endoscopy (CTVE). Comparison of CTA and DSA was based on North American Symptomatic Carotid Endarterectomy Trial (NASCET) standard: mild stenosis (10%-29%), moderate stenosis (30%-69%), severe stenosis (70%-99%), and occlusion (100%). Results CTA of 98 carotid arteries showed 12 normal, 26 mild stenosis, 32 moderate, 19 severe stenosis and 9 occlusion. In 49 patients with carotid artery stenosis, the total coincidence rate of CTA between DSA in the diagnosis of carotid stenosis was 96.94% (95/98). The coincidence rate of CTA between DSA in severe stenosis and occlusion, mild stenosis, and moderate stenosis was 100% (28/28), 96.15% (25/26) and 93.75% (30/32), respectively. CTA could also reveal calcific plaque, fibrous plaque and soft plaque, CT value in each plaque type could be estimate. The CT value of calcific plaque, fibrous plaque, and soft plaque was (489±113) HU, (51±19) HU, and (6±28) HU, respectively. Conclusion CTA can accurately and objectively diagnose carotid stenosis, and evaluate the plaque. It may replace DSA in the assessment of carotid artery stenosis.