ABSTRACT
Objective To evaluate the efficacy of MR angiogrphy(MRA) for detecting cerebral vasospasm after subarachnoid hemorrage(SAH) and compare it with spiral CT angiography(CTA).Methods Ten patients with SAH under MRA and CTA studies were performed within 24 hours after MRA,which was performed 5 to 10 days after SAH.Maximum intensity projection(MIP) images were produced for MRA and CTA studies.Five arterial locations were examined for spasm:the suprasellar internal carotid artery(ICA),the M1 and M2 segments of the middle cerebral artery(MCA),the A1 and A2 segments of the anterior cerebral artery(ACA).Vasospasm was cate- gorized as none,mild(50 % reduction).Results The overall correlation between MRA and CTA was 82 %(r=0.76),but it was better for proximal than distal lo- cations vessels.Agreement between MRA and CTA was greater for no spasm(89%) and severe spasm(100%)(r= 0.85～0.91)than for mild(56%)or moderate(67%)spasm(r=0.21～0.51).Conclusion MRA is highly accu- rate in the detecting no spasm or severe cerebral vasospasm in proximal arterial locations vessels;it is less accurate in detecting mild and moderate spasm in distal locations vessels.