Application of 3D-SPACE sequence combined with 3D-TOF MR angiography in follow-up for intracranial aneurysm after stent-assisted coil embolization

Abstract

Objective To explore the application value of three dimensional T1 weighted sampling perfection with application-optimized contrasts by using different flip angle evolutions (3D T1-SPACE) combined with three dimensional time of flight MR angiography (3D-TOF MRA) in the follow-up of stent-assisted coil embolization for intracranial aneurysm. Methods From December 2017 to October 2018, 25 patients with intracranial aneurysm who underwent stent-assisted coil embolization in Henan Provincial People′s Hospital were enrolled. All of them had wide neck intracranial aneurysms and were followed up for 6 to 10 months after endovascular treatment using 3D-TOF MRA, 3D T1-SPACE sequence and DSA. The DSA and 3D-TOF MRA were performed to evaluate aneurysm remnants using Raymond grade scale. Meanwhile, 3D-TOF MRA and 3D T1-SPACE sequence were performed to evaluate in-stent lumen visibility using the 4-point scale. The paired sample Wilcoxon test was used to evaluate the aneurysm remnants and the parent artery patency. DSA was used as the gold standard to calculate the specificity and accuracy of the aneurysm remnants evaluated by 3D-TOF MRA. Results Six to ten months′ follow up after the procedure, for aneurysm occlusion, the Raymond grade scale of the 25 patients evaluated by DSA indicated grade 1 in 23 patients, 2 in 1 and 3 in 1. For patients evaluated by 3D-TOF MRA, the results demonstrated grade 1 in 21 patients, 2 in 3 and 3 in 1. There was no difference between the 2 methods (Z=-0.557, P=0.577). The in-stent lumens of parent vessel evaluated by 3D-TOF MRA showed that there were 14 patients with grade 3, 8 patients with grade 2 and 3 patients with grade 1. However, 3D T1-SPACE demonstrated that all 25 patients were grade 4. The 3D T1-SPACE was superior to evaluate the in-stent lumens than 3D-TOF MRA (Z=-4.484, P<0.001). Taking DSA as standard, the specificity and accuracy of the aneurysm remnants evaluated by 3D-TOF MRA were 86.9% (20/23) and 84.0% (21/25), respectively. Conclusion 3.0 T 3D T1-SPACE MR sequence can be used to assess parent artery patency, with in-stent lumen being clearly visible. 3D-TOF MRA can evaluate intracranial aneurysm remnants. The combination of these two MRI imaging techniques can be used as an optional follow-up evaluation after the endovascular treatment of intracranial aneurysms. Key words: Intracranial aneurysm; Magnetic resonance imaging; Embolization, therapeutic; Follow-up studies