Feasibility and diagnostic performance of PETRA-MRA for postoperative follow-up of intracranial aneurysms: a...

Metal-related susceptibility artifacts have long limited the use of magnetic resonance angiography (MRA) for postoperative surveillance after intracranial aneurysm interventions. Pointwise encoding time reduction with radial acquisition (PETRA) substantially reduces metal-induced artifacts. This study aimed to evaluate the performance of PETRA-MRA in depicting parent artery image quality and aneurysm occlusion status at postoperative day 1 (T0) and 6 months (T1), and to explore its feasibility as a noninvasive alternative to digital subtraction angiography (DSA) for follow-up.

In this prospective study, 100 patients harboring 100 intracranial aneurysms underwent time-of-flight MRA (TOF-MRA), PETRA-MRA, and DSA at both T0 and T1. Parent artery image quality was compared across time points and treatment modalities stent-assisted coiling (SAC) vs. flow diverter (FD) placement alone. A parsimonious cumulative logit regression model was performed to identify factors associated with PETRA-MRA image quality. Using DSA as the reference standard, the sensitivity, specificity, and accuracy of PETRA-MRA for assessing aneurysm occlusion were calculated.

Across both treatment groups, PETRA-MRA demonstrated significantly improved image quality at T1 compared with T0. At T1, both TOF-MRA and PETRA-MRA yielded higher image quality scores in the FD group than in the SAC group. Regression analysis indicated that none of the pre-specified covariates demonstrated a statistically significant independent association with PETRA-MRA image quality at T1 based on bootstrap-based inference. Complete occlusion rates increased markedly from T0 to T1: from 21.4% to 71.4% in the FD group and from 80.6% to 91.7% in the SAC group. Using DSA as the reference standard, PETRA-MRA demonstrated higher diagnostic accuracy than TOF-MRA at both time points in the SAC group, with accuracies of 94.44% in T0 and 97.67% in T1.

PETRA-MRA demonstrates improved diagnostic performance at mid-term follow-up compared with the early postoperative period. Its marked ability to reduce metal artifacts and enhance visualization of both the parent artery and aneurysm lumen supports its potential as an effective, noninvasive alternative to DSA for long-term surveillance after intracranial aneurysm treatment.