Could MR Angio Replace Digital Subtraction Angiography for Verification of Occlusion Rate of Cerebral Aneurysms?

Background/Objectives: Cerebral aneurysms affect 3-5% of the population and carry a risk of rupture. Post-treatment imaging is essential to detect residual or recurrent filling. Digital subtraction angiography (DSA) is the gold standard, but it is invasive and can have complications. Magnetic resonance angiography (MRA) is a non-invasive alternative, but its reliability in follow-up remains debated. This study evaluated the diagnostic performance of MRA compared to DSA in detecting residual flow after endovascular treatment of intracranial aneurysms. Primary outcomes were MRA's sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) and its potential to reduce or replace DSA in follow-up. Methods: A retrospective single-center study included patients ≥ 18 years treated endovascularly for ruptured or unruptured intracranial aneurysms during 2018-2021. Each follow-up case with both DSA and MRA was independently assessed by neuroradiologists, using DSA as the reference standard. Diagnostic performance metrics were calculated. Results: Of 400 screened cases, 198 were included. MRA and DSA findings agreed in 78.3% of cases. MRA showed 69.7% sensitivity and 80.0% specificity. PPV was 41.1%, and NPV was 93.0%. There were 33 false positives and 10 false negatives. Only one false negative led to retreatment, and none of the false positives required intervention. Conclusions: MRA shows high reliability in ruling out residual aneurysm flow due to its strong NPV. Despite limitations in confirming recurrence, MRA might be a useful first-line follow-up tool, with DSA reserved for inconclusive, unclear, or artifact cases.