Maximum internal carotid arterial stenosis: assessment with rotational angiography versus conventional intraarterial digital subtraction angiography.

PURPOSE: To assess how often rotational angiography depicts more severe internal carotid arterial stenosis compared with conventional intraarterial digital subtraction angiography (DSA) in two or three projections and how frequently this factor may affect patient treatment.
MATERIALS AND METHODS: Rotational angiography (16 or 32 projections) was performed in addition to DSA in 47 stenotic internal carotid arteries (ICAs) in 38 symptomatic patients. ICA stenosis was measured independently at DSA and at rotational angiography with North American Symptomatic Carotid Endarterectomy Trial criteria. The degree of stenosis was categorized as 0%-29%, 30%-49%, 50%-69%, or 70%-99%.
RESULTS: In three ICAs, rotational angiography was nondiagnostic. In 28 of the remaining 44 ICAs, the degree of stenosis was categorized similarly with DSA and rotational angiography, whereas with rotational angiography, 15 ICAs were classified one category higher and one ICA was classified two categories higher, owing to the increased number of projections available. Seventy percent to 99% stenosis was demonstrated in 18 ICAs with DSA and in 25 ICAs with rotational angiography. Thus, rotational angiography could have facilitated a change in the optimal treatment (from nonsurgical treatment to carotid arterial endarterectomy) in seven ICAs.
CONCLUSION: Compared with DSA in two or three projections, rotational angiography frequently depicts more severe ICA stenosis. This indicates a limitation of DSA in depicting the maximum ICA stenosis.