OBJECTIVETo assess the accuracy of computed tomography angiography (CTA) in quantifying atherosclerotic area in the vascular wall of the carotid artery in comparison with high-resolution magnetic resonance imaging (MRI).

METHODSEighteen subjects (15 males and 3 females aged 63-/+8 years) with >or=50% stenosis in at least one carotid artery were enrolled in this study. CTA and high-resolution MRI scans (in-plane pixel size of 0.25 mmx0.25 mm for both) were conducted within 1 week on a multi-slice spiral CT scanner and a 1.5T MR scanner (Signa, GE Medical Systems), respectively. CTA images were matched with MR images with the carotid bifurcation as the mark. For each patient, multiple matched slices with carotid atherosclerotic plaques in the bilateral carotid arteries were selected to measure the outer wall boundary (OWB) area, lumen area and wall area. Bland-Altman analysis and Pearson correlation coefficients were used to analyze the correlations of the area measurements between CTA and high-resolution MRI.

RESULTSA wide range of lesion size (vascular wall area) was found in these patients. Strong correlations were noted between CTA and high-resolution MRI with the correlation coefficients for OWB area, lumen area and wall area of 0.98, 0.98 and 0.96, respectively. The mean differences between CTA and high-resolution MRI were 0.16-/+5.71 mm(2), 4.47-/+1.44 mm(2) and -4.31-/+5.73 mm(2) for OWB area, lumen area and wall area, respectively.

CONCLUSIONCompared to high-resolution MRI, CTA is also a reliable method to measure carotid vascular wall area. CTA might become an alternative modality to high-resolution MRI for follow-up examination of patients with carotid artery atherosclerosis, especially in uncooperative patients or patients with contra-indications for MRI.