Golden-angle radial sparse parallel (GRASP) magnetic resonance angiography (MRA) for endoleak evaluation after endovascular repair of the aorta: a prospective comparison to conventional time-resolved MRA.

Background: Time-resolved angiography with interleaved stochastic trajectories (TWIST) magnetic resonance angiography (MRA) may obscure smaller vessels and is highly susceptibility to motion artifacts, potentially reducing endoleak detection accuracy after endovascular aortic repair (EVAR). The novel golden-angle radial sparse parallel (GRASP) sequence enhances spatial and temporal resolution with continuous, motion-robust datasets, showing promise for accurate endoleak detection post-EVAR. This study aimed to compare the diagnostic effectiveness of contrast-enhanced compressed-sensing radial GRASP-volume interpolated breath-hold examination (VIBE) sequence with standard contrast-enhanced dynamic TWIST-VIBE sequence in patients with inconclusive computed tomography angiography (CTA) findings regarding endoleak after EVAR.

Methods: This single-center prospective study consecutively enrolled adults with inconclusive findings regarding the presence or type of endoleak in multiphasic CTA following EVAR for abdominal aortic aneurysms. Participants underwent contrast-enhanced MRA, acquiring dynamic TWIST-VIBE and GRASP-VIBE sequences. Two independent radiologists assessed the datasets for image quality, diagnostic confidence, and the presence and type of endoleak. Additionally, quantitative assessments with signal-to-noise ratios (SNR) and contrast-to-noise ratios (CNR) were performed. Statistical analyses included interrater and intermethod agreement, and diagnostic performance testing.

Results: Twenty participants (mean age, 72±9 years; 13 males) were included. GRASP-VIBE demonstrated superior image quality over TWIST-VIBE sequence with predominantly absent motion artifacts and increased diagnostic confidence (all P<0.001). Diagnostic performance significantly improved for detecting type II endoleaks in GRASP-VIBE compared to TWIST-VIBE scans [area under the curve (AUC): 0.96 vs. 0.73; P=0.04]. Diagnostic accuracy improved with GRASP-VIBE for overall (AUC: 0.94 vs. 0.79) and endoleak type I detection (AUC: 1.0 vs. 0.90), however, not significantly (P≥0.05). TWIST-VIBE sequences demonstrated significantly higher SNR for measurements in the clotted aneurysm sac (P=0.01). No significant differences were observed in CNR for the aorta and any aneurysm sacs across the compared imaging sequences.

Conclusions: Compressed-sensing dynamic GRASP-VIBE sequence, with its superior image quality, diagnostic confidence, and performance, may be preferred over standard TWIST-VIBE sequence in inconclusive endoleak cases.