Diagnostic accuracy of 3D time-of-flight MR angiography compared with digital subtraction angiography for follow-up of coiled intracranial aneurysms: influence of aneurysm size

Abstract

Background and purpose: 3D time-of-flight MR angiography (3D TOF MRA) may be used as noninvasive alternative to digital subtraction angiography (DSA) for the follow-up of patients with intracranial aneurysms treated with Guglielmi detachable coils (GDCs). We aimed to determine the influence of aneurysm size and location on diagnostic accuracy of 3D TOF MRA for follow-up of intracranial aneurysms treated with GDCs.

Materials and methods: Two hundred and one 3D TOF MRAs in 127 consecutive patients with 136 aneurysms were compared with DSA as standard of reference. Sensitivity and specificity of 3D TOF MRA for detection of residual or reperfusion of the aneurysms was calculated with regard to aneurysm size and location.

Results: Overall sensitivity and specificity of MRA was 88.5% and 92.9%, respectively. Sensitivity was lower for aneurysms <or=5 mm (72.2%) and <or=3 mm (63.6%). In addition to the small aneurysm size, interpretation of MR angiograms was compromised by susceptibility artifacts at the air-bone interface, arterial overlap, and pulsation-induced artifacts. The small number of disagreements between MRA and DSA hampered reliable interpretation of the possible influence of aneurysm location on MRA accuracy.

Conclusion: The sensitivity of 3D TOF MRA for detection of reperfusion or residual perfusion of coiled intracranial aneurysms varies considerably depending on the size of the aneurysms. No conclusions can be drawn regarding a possible influence of aneurysm location on diagnostic accuracy of 3D TOF MRA. These findings may influence the decision about whether to replace DSA by 3D TOF MRA for the follow-up of patients with intracranial aneurysms treated with GDCs.

Fig 1.

Agreement in detection of residual flow at the neck of an aneurysm of the anterior cerebral artery after treatment with detachable coils seen on DSA (A, black arrow). Unenhanced 3D TOF MRA (B) and MIP reconstruction (C) showing the residual flow (white arrows) in agreement with DSA.

Fig 2.

Overestimation of a completely occluded aneurysm of the anterior communicating artery seen on DSA (A, black arrow). Unenhanced 3D TOF MR angiography (B) and MIP reconstruction (C) showing a small residual perfusion at the neck of the aneurysm (white arrows).

Fig 3.

Overestimation of a small residual perfusion of a coiled aneurysm of the middle cerebral artery seen on DSA (A, black arrow). Contrast-enhanced 3D TOF MRA (B) and MIP reconstruction (C) showing a large residual neck (white arrows).

Fig 4.

Underestimation of a residual perfusion of the neck of a basilaris tip aneurysm seen on DSA (A, black arrow). Contrast-enhanced TOF MRA (B) and MIP reconstruction (C) showing complete occlusion (white arrows).

Fig 5.

Underestimation of a large residual neck of an aneurysm of the anterior communicating artery seen on DSA (A, black arrow). Unenhanced TOF MRA (B) shows a small residual perfusion of the aneurysm neck (white arrow).