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FIG 6. A, Right anterior oblique DSA image reveals high-grade stenosis (arrow) in the left ICA; degree of stenosis was calculated to be 82%. A high-grade stenosis is also present at the origin of the left external carotid artery.
B–D, CT angiograms verify the stenosis of the ICA (short arrow). Left sagittal view of 3D reconstruction MIP image (B) also shows stenosis of the external carotid artery. CT angiographic sagittal (C) and cross-sectional (D) MPR views reveal the stenosis in the ICA (short arrow) without over projection of mural calcification (long arrow). On the MIP image (B), mural calcification (long arrows) is over projected with the lumen. The degree of stenosis was considerably underestimated with CT angiography using the MPR measurements. However, the hemodynamic significance of the stenosis was obvious in the interactive interpretation of CT angiograms.
E and F, Rotational angiograms show that notable pulsation movement of the stenosed artery in the craniocaudal direction (arrow) can be detected when comparing the location of the stenosis to the upper endplate of the third cervical vertebra between these two images obtained in different phases of the cardiac cycle. The movement artifact might have caused extra blurring of the vessel wall on CT angiograms obtained without electrocardiographic gating.
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