FIG 3. A, IA-DSA (right carotid arteriogram) obtained 16 days after acute SAH. A 5-mm aneurysm is visible in the AComA (arrowheads). There is a slight narrowing of the ICA (rating = 1), but overall there is no angiographic vasospasm.

B and C, MR angiograms (32/8/2; flip angle = 17°) obtained 2 hours before IA-DSA. The aneurysm is clearly visible (arrowheads). On the MIP image (B), some portions of arteries are poorly visualized on both sides, suggesting the presence of a significant vasospasm (rating = 2 for both ICA and ACA and 1 for both MCAs). This is a false interpretation, which can be avoided by looking at the native slices (C). Significant pulsation artifacts (arrow) are present around the arteries, leading to a discontinuous aspect of vessels on the MIP image.