Role of spiral CT angiography and duplex ultrasound in the evaluation of carotid artery stenosis

Seventy carotid arteries were examined; forty-nine arteries showed insignificant lesions on both tests and were excluded and twenty-one carotids demonstrated varying degrees of stenosis on CT angiography. Duplex ultrasound missed a stenotic lesion affecting the distal internal carotid artery [ICA] in one case. The degree of CT angiographic stenosis was overestimated by duplex scanning in three other cases. Further, an ICA that was shown on duplex scanning to be totally occlusive proved on CT imaging to be a pre-occlusive one. The degree of stenosis was identical on both CT angiography and duplex ultrasound in the remaining 16 arteries