Computed angiotomography of unruptured cerebral aneurysms

Twenty-seven unruptured cerebral aneurysms in 25 patients were detected by computed angiotomography. A comparison of the computed an- giotomographic features in common aneurysm sites with plain CT and con-ventional arteriography was carried out. An isodense, round cisternal defect and a calcification or high-density mass in the basal cisterns on plain CT are important findings suggestive of unruptured aneurysms larger than 7 mm in diameter. The identification of the aneurysm, as well as of the afferent and efferent arteries on computed angiotomography is essential for the direct di-agnosis of smaller unruptured aneurysms related to the circle of Willis. This is possible in a number of cases when the aneurysms are relatively large. It appears that the aneurysm size must be larger than 3 mm in diameter to permit its recognition on the basis of angiotomography and the avoidance of false-positive findings.