Multidetector CTA in the quantification of internal carotid artery stenosis: value of different reformation techniques and axial source images compared with selective carotid arteriography.

PURPOSE

To evaluate the role of 4 different reformation techniques and axial images from multidetector computed tomographic angiography (MDCTA) versus selective carotid arteriography (SCA) in patients with internal carotid artery (ICA) stenosis.

METHODS

Imaging studies from 50 patients (43 men; mean age 70.3+/-8.0 years, range 51-85) with known cerebrovascular disease who underwent MDCTA and SCA in a single university hospital were retrospectively analyzed. Axial images, multiplanar reformation (MPR), curved planar reformation (CPR), volume rendering threshold (VRT), and virtual angioscopy (VA) images were reviewed by 2 independent observers who were blinded to the results of SCA, which served as the gold standard. The degree of stenosis was categorized as 0%-49%, 50%-69%, or 70%-99%; a stenosis >70% was considered as hemodynamically significant.

RESULTS

Thirty-four hemodynamically significant stenoses were identified on SCA. The agreement with SCA images was good for both observers using axial CT images (kappa = 0.89 for observer 1 and 0.88 for observer 2); corresponding results for MPR and CPR were kappa = 0.91 and 0.92 for observer 1 and 0.88 and 0.91 for observer 2, respectively. VRT (kappa = 0.72 for observer 1 and 0.66 for observer 2) and VA (kappa = 0.74 for observer 1 and 0.70 for observer 2) showed a slightly inferior correlation with SCA images. Sensitivities for reformations and axial CT images were 100% each; corresponding specificities ranged from 85% to 95%.

CONCLUSION

Axial images as well as all 4 reformation techniques agreed well with SCA in the grading of ICA stenosis.