Detection and characterization of intracranial aneurysms with 16-channel multidetector row CT angiography: a prospective comparison of volume-rendered images and digital subtraction angiography

Abstract

Background and purpose: The aim of our study was to compare multidetector row CT angiography (MDCTA) with digital subtraction angiography (DSA) in the detection and characterization of intracranial aneurysms.

Materials and methods: In our blinded prospective study, 85 patients with suspected intracranial aneurysm (47 women, 38 men; age range, 19-83 years) underwent both 16-channel MDCTA and DSA. The MDCT angiograms were interpreted for the presence, location, size, ratio of the neck to the dome (N/D ratio), and lobularity of the aneurysms and relationship of the aneurysm with the adjacent arterial branches, by using volume-rendering techniques. MDCTA and DSA images (reference standard) were interpreted by 2 independent readers, and the results were compared.

Results: A total of 93 aneurysms were detected at DSA in 71 patients, whereas no aneurysms were detected in 14 patients. Compared with DSA, the overall sensitivity, specificity, and accuracy of MDCTA on a per-aneurysm basis were 92.5%, 93.3%, and 92.6%, respectively, for both independent readers. For aneurysms of <3 mm, however, MDCTA had a sensitivity of 74.1% for reader 1 and 77.8% for reader 2. There was excellent agreement between readers in the detection of aneurysms (kappa = 0.822). In addition, MDCTA was also accurate in determining N/D ratio of aneurysms, aneurysm lobularity, and adjacent arterial branches.

Conclusion: MDCTA is accurate in the detection and characterization of intracranial aneurysms and can be used as a reliable alternative imaging technique to DSA in selected cases.

Fig 1.

A 72-year-old woman with subarachnoid hemorrhage. A and B, Volume-rendered MDCTA images obtained with right anterior oblique (A) and lateral (B) projections demonstrate a bilobed aneurysm at the bifurcation of the right internal carotid artery (arrow). There are also 2 small aneurysms at the posterior communicating artery (long arrow) and the anterior choroidal artery (arrowhead). The anterior choroidal artery aneurysm was missed by reader 2 at initial interpretation. C, The same aneurysms (arrows and an arrowhead) are also depicted on the lateral projection DSA image of the right internal carotid artery.

Fig 2.

A 71-year-old woman with subarachnoid hemorrhage. A, Left anterior oblique projection volume-rendered MDCTA image shows a saccular aneurysm arising from the anterior communicating artery (arrow). The neck of aneurysm was graded as wide (grade 3; N/D ratio, >2/3) by both readers on the basis of volume-rendered images. B, DSA image of the left internal carotid artery, obtained in a projection similar to that of the DSA image shown in A, shows the narrow (grade 1; N/D ratio, <1/3) neck of the aneurysm (arrow).

Fig 3.

A 57-year-old man with subarachnoid hemorrhage. A, Superior projection volume-rendered MDCTA image shows a small aneurysm of the anterior communicating artery (arrow). With this technique, the neck of the aneurysm is obscured by both overlying anterior cerebral arteries despite multiple projections (not shown). B, Anteroposterior projection volume-rendered MDCTA image with automated segmentation shows laterally and inferiorly directed saccular aneurysm at the anterior communicating artery (arrow). The relations of the aneurysmal neck can be demonstrated better with this postprocessing software. C, Corresponding DSA image of the left internal carotid artery shows the same aneurysm (arrow).