Comparison of 3D TOF-MRA and 3D CE-MRA at 3 T for imaging of intracranial aneurysms

Purpose: To compare 3 T elliptical-centric CE MRA with 3 T TOF MRA for the detection and characterizationof unruptured intracranial aneurysms (UIAs), by using digital subtracted angiography (DSA) as reference.Materials and methods: Twenty-nine patients (12 male, 17 female; mean age: 62 years) with 41 aneurysms(34 saccular, 7 fusiform; mean diameter: 8.85 mm [range 2.0–26.4 mm]) were evaluated with MRA at3 T each underwent 3D TOF-MRA examination without contrast and then a 3D contrast-enhanced (CE-MRA) examination with 0.1 mmol/kg bodyweight gadobenate dimeglumine and k-space elliptic mapping(Contrast ENhanced Timing Robust Angiography [CENTRA]). Both TOF and CE-MRA images were used toevaluate morphologic features that impact the risk of rupture and the selection of a treatment. Almosthalf (20/41) of UIAs were located in the internal carotid artery, 7 in the anterior communicating artery,9 in the middle cerebral artery and 4 in the vertebro-basilar arterial system.All patients also underwent DSA before or after the MR examination.Results: The CE-MRA results were in all cases consistent with the DSA dataset. No differences werenoted between 3D TOF-MRA and CE-MRA concerning the detection and location of the 41 aneurysmsor visualization of the parental artery. Differences were apparent concerning the visualization of mor-phologic features, especially for large aneurysms (>13 mm). An irregular sac shape was demonstratedfor 21 aneurysms on CE-MRA but only 13/21 aneurysms on 3D TOF-MRA. Likewise, CE-MRA permittedvisualization of an aneurismal neck and calculation of the sac/neck ratio for all 34 aneurysms with aneck demonstrated at DSA. Conversely, a neck was visible for only 24/34 aneurysms at 3D TOF-MRA. 3DCE-MRA detected 15 aneurysms with branches originating from the sac and/or neck, whereas brancheswere recognized in only 12/15 aneurysms at 3D TOF-MRA.Conclusion: For evaluation of intracranial aneurysms at 3 T, 3D CE-MRA is superior to 3D TOF-MRA forassessment of sac shape, detection of aneurysmal neck, and visualization of branches originating fromthe sac or neck itself, if the size of the aneurysm is greater than 13 mm. 3 T 3D CE-MRA is as accurate andeffective as DSA for the evaluation of UIAs.