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.

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.