3D rotational angiography: the new gold standard in the detection of additional intracranial aneurysms

Abstract

Background and purpose: During surgery of symptomatic aneurysms, additional small angiographic occult aneurysms are commonly found. With 3D rotational angiography (3DRA) small aneurysms are more easily depicted than with digital subtraction angiography (DSA). In this study we compare 3DRA with DSA in the depiction of small additional aneurysms.

Materials and methods: Three hundred fifty 3D datasets of 1 vascular tree of 350 patients with at least 1 intracranial aneurysm on the dataset were re-evaluated for the presence of additional aneurysms by 2 observers in consensus. Two other observers, blinded to the 3D images, re-evaluated DSA images of the same 350 vascular trees for these additional aneurysms. Results were compared.

Results: In 350 3D datasets, 350 target aneurysms and 94 additional aneurysms were detected. The mean size of 94 additional aneurysms was 3.54 mm (median, 3; range, 0.5-17 mm). The proportion of aneurysms <or=3 mm was significantly higher in additional aneurysms (61 of 94, 65%) than in the target aneurysms (61 of 350, 17%) (chi(2), P < .0001). Of 94 additional aneurysms, 27 (29%) were missed on DSA by both observers. The mean size of the missed aneurysms was 1.94 mm (median, 2; range, 0.5-4 mm). The proportion of aneurysms <or=3 mm in missed additional aneurysms (26 of 27, 96%) was significantly higher than that in all additional aneurysms (61 of 94, 65%) (chi(2), P = .0035). The location of missed additional aneurysms was not different from the location of all additional aneurysms.

Conclusion: 3DRA depicts considerably more small (<or=3 mm) additional aneurysms than DSA. In selected patients, accurate detection of these aneurysms may have consequences for the choice of treatment technique and for the frequency and duration of imaging follow-up.

Fig 1.

A 2-mm middle cerebral artery aneurysm missed on DSA in 45-year-old man. A–D, DSA in 4 projections fails to depict an aneurysm. E, Demonstration of an aneurysm on 3DRA (arrow).

Fig 2.

Two angiographically occult additional microaneurysms adjacent to a ruptured posterior inferior cerebellar artery aneurysm in a 53-year-old woman. A and B, DSA in 2 projections demonstrates a posterior inferior cerebellar artery aneurysm. C, 3DRA detects 2 additional microaneurysms (arrows).

Fig 3.

A 44-year-old woman with subarachnoid hemorrhage. A and B, DSA in 2 projections reveals a posterior communicating artery aneurysm and an asymptomatic left parietal arteriovenous malformation. C, 3DRA shows, besides the posterior communicating artery aneurysm, 3 additional small aneurysms on the supraclinoidal carotid and proximal A1 arteries (short arrows) and on a fenestrated anterior communicating artery (long arrow).

Fig 4.

Four examples of small additional aneurysms missed on DSA. A, A very small (0.5 mm) A1 aneurysm (arrow) in a patient with a ruptured middle cerebral artery aneurysm. B, Two supraclinoidal aneurysms (arrows) in a patient with a ruptured posterior communicating artery aneurysm. C, Two middle cerebral artery aneurysms (arrows) in a patient with a ruptured pericallosal artery aneurysm (not shown). D, An intracavernous carotid artery aneurysm (arrow) in a patient with a large ophthalmic artery aneurysm, symptomatic by mass effect.

Fig 5.

Four more examples of missed additional aneurysms on DSA. A, A small middle cerebral artery aneurysm (arrow) in a patient with a ruptured anterior communicating artery aneurysm. B, Two small additional aneurysms on the anterior communicating and middle cerebral arteries (arrows) in a patient with a ruptured anterior communicating artery aneurysm. C, A very small (0.5 mm) A1 aneurysm (arrow) in a patient with a ruptured posterior communicating artery aneurysm. D, A small additional anterior communicating artery aneurysm (arrow) in a patient with a ruptured middle cerebral artery aneurysm.