PURPOSE: To compare computed tomographic (CT) angiography and magnetic reso
nance (MR) angiography with intraarterial digital subtraction angiography (
DSA) in the detection of intracranial aneurysms.
MATERIALS AND METHODS: One hundred forty-two patients underwent intraarteri
al DSA to detect aneurysms. CT angiography, three-dimensional time-df-fligh
t angiography, and intraarterial DSA were performed contemporaneously. Film
hard-copy images and maximum intensity projection reconstructions of the C
T angiograms and MR angiograms were reviewed at different times.
RESULTS: The accuracy per patient for the best observer was 0.87 at CT angi
og- and 0.85 at MR angiography. The accuracy per aneurysm for the best was
0.73 at CT angiography and 0.67 at MR angiography. Differences between read
ers and modalities were not significant. Interobserver agreement was good:
K value of 0.73 for CT angiography and of 0.74 for MR angiography. The sens
itivity fbr detection of aneurysms smatter than 5 mm was 0.57 for Cf angiog
raphy and 0.35 for MR angiography compared with 0.94 and 0.86, respectively
, for of aneurysms 5 mm or larger. The accuracy of both CT angiography and
angiography was lower for detection of internal carotid artery aneurysms co
mpared with that at other sites. With low observer confidence, the likeliho
od of correct interpretation was significantly poorer.
CONCLUSION: CT angiography and MR angiography have limited sensitivity in t
he detection of small aneurysms but good interobserver agreement. There is
no significant difference in diagnostic performance between the noninvasive