Evaluation of cerebral aneurysms with helical CT: correlation with conventional angiography and MR angiography.

PURPOSE: To evaluate detection of intracranial aneurysms with helical computed tomography (CT) and compare the results with those of conventional angiography and magnetic resonance (MR) angiography. MATERIALS AND METHODS: Twenty-one patients with 30 intracranial aneurysms were studied with helical CT and conventional angiography; 17 of the patients (24 aneurysms) also underwent MR angiography. RESULTS: All aneurysms 3 mm or larger in greatest dimension were seen with helical CT and MR angiography; no aneurysms smaller than 3 mm were apparent with either modality. Of the 21 aneurysms demonstrated with both helical CT and MR angiography, 11 were seen equally well with both techniques; six were seen better with helical CT owing to flow-related or motion artifact at MR angiography, and four were seen better with MR angiography because calcium partially obscured them at helical CT. CONCLUSION: Helical CT is a promising noninvasive method of imaging the intracranial vasculature and is comparable with standard MR angiographic techniques in demonstrating aneurysms.