Diagnostic Performance of Pointwise Encoding Time Reduction with Radial Acquisition Subtraction-based MR Angiography in the Follow-up of Intracranial Aneurysms after Clipping.

Purpose: While follow-up assessment of clipped aneurysms (CAs) using magnetic resonance angiography (MRA) can be challenging due to susceptibility artifacts, a novel MRA sequence pointwise encoding time reduction with radial acquisition (PETRA) subtraction-based MRA, has been developed to reduce these artifacts. The aim of the study was to validate the diagnostic performance of PETRA-MRA by comparing it with digital subtraction angiography (DSA) as a reference for follow-up of CAs using a 3T MR scanner.

Methods: Patients with clipping who underwent both PETRA-MRA and DSA between September 2019 and December 2021 were retrospectively included. Two neuroradiologists independently reviewed with the reconstructed images of PETRA-MRA to assess the visibility of the arteries around the clips and aneurysm recurrence or remnants of CA using a 3-point scale. The diagnostic accuracy of PETRA-MRA was evaluated in comparison to DSA.

Results: The study included 34 patients (28 females, mean age 59 ± 9.6 years) with 48 CAs. The PETRA-MRA allowed visualization of the parent vessels around the clips in 98% of cases, compared to 39% with time-of-flight (TOF) MRA (p < 0.0001). The DSA confirmed 14 (29.2%) residual or recurrent aneurysms. The PETRA-MRA demonstrated a high accuracy, specificity, positive predictive value, and negative predictive value of 99.2%, 100%, 100%, and 97.8%, respectively, while the sensitivity was 66.7%.

Conclusion: This retrospective study demonstrates that PETRA-MRA provides excellent visibility of adjacent vessels near clips and has a high diagnostic accuracy in detecting aneurysm remnants or recurrences in CAs. Further prospective studies are warranted to establish its utility as a reliable alternative for follow-up after clipping.