Spiral CT of intracranial aneurysms: correlation with digital subtraction and magnetic resonance angiography.

Spiral CT and magnetic resonance angiography (MRA) were performed in ten patients with 14 intracranial aneurysms known from conventional angiography. All lesions, the smallest 3 mm in diameter, were visible on spiral CT and MRA. The neck of the aneurysm and its anatomical relations could very accurately be determined in all cases. Advantages of spiral CT over MRA are: a short acquisition time with reduction of motion artefacts, no dependence on flow rate or cardiac output, and excellent visualisation of calcification, thrombus and bony landmarks. Disadvantages are the necessity for iodinated contrast medium, long postprocessing and reconstruction time and the possibility of overlap of bone and venous blood.