Ultrashort Echo Time Magnetic Resonance Angiography in Follow-up of Intracranial Aneurysms Treated With Endovascular Coiling: Comparison of Time-of-Flight, Pointwise Encoding Time Reduction With Radial Acquisition, and Contrast-Enhanced Magnetic Resonance Angiography.

Abstract

The optimal magnetic resonance angiography (MRA) sequence for assessing the aneurysm occlusion state or in-stent flow after endovascular coiling is not well established. To evaluate the diagnostic performance of pointwise encoding time reduction with radial acquisition (PETRA)-MRA in patients who underwent endovascular coiling relative to that of time-of-flight (TOF)-MRA and contrast-enhanced (CE)-MRA. We evaluated the aneurysm occlusion state using digital subtraction angiography (DSA) and MRA. In patients who underwent stent-assisted coiling, we estimated the visibility of in-stent flow. We enrolled 189 patients with assessable TOF, PETRA, and CE-MRAs after coiling. In patients who underwent simple coiling (128 patients), PETRA showed a higher sensitivity in the detection of residual flow than TOF and CE (PETRA, 100%; CE, 83%; TOF, 80%). There were no significant differences in the height of residual flow between DSA (0.68± 1.45mm) and PETRA (0.70± 1.50mm; P=1.000). In patients who underwent stent-assisted coiling (61 patients), PETRA showed the highest sensitivity (88%) in detecting residual flow (CE, 56%; TOF, 31%). Regarding in-stent flow, PETRA, CE, and TOF showed visual scores of≥3 with frequencies of 96.7%, 85.2%, and 37.7%, respectively. Relative signal-to-noise ratio of PETRA (0.62± 0.18) was significantly higher than that of CE (0.56± 0.12) and TOF (0.39± 0.12; P <.001 for both). PETRA-MRA showed excellent diagnostic performance in terms of residual flow detection and in-stent flow assessment. PETRA could be a versatile alternative sequence for following up patients with coiled aneurysm.