Sato Keisuke, Asano Akihiro, Kobayashi Tsutomu, Aoki Hiroshi, Jinguji Shinya, Seto Hiroki, Demachi Hiroshi, Hasegawa Hitoshi, Fujii Yukihiko
Department of Neurosurgery, Toyama Prefectural Central Hospital, Toyama, Toyama, Japan.
Department of Medical Technology, Toyama Prefectural Central Hospital, Toyama, Toyama, Japan.
J Neuroendovasc Ther. 2021;15(6):352-359. doi: 10.5797/jnet.oa.2020-0039. Epub 2021 Jan 15.
OBJECTIVE: Pointwise encoding time reduction with radial acquisition (PETRA) using magnetic resonance angiography (MRA) is a non-enhanced MRA technique employing an ultrashort echo time, and is known to significantly reduce the magnetic susceptibility of coils and stents during post-embolization imaging. We evaluated the quality of PETRA-MRA images for use at the follow-up assessment of stent-assisted coil embolization procedures performed to treat aneurysms. METHODS: A total of six aneurysm patients who were treated by stent-assisted coil embolization were included. All patients underwent PETRA-MRA, time-of-flight (TOF)-MRA performed with MAGNETOM Skyra (Siemens), and digital subtraction angiography (DSA) performed with Infinix Celeve-i INFX-8000V (Canon Medical Systems) and Allura Clarity FD20/15 (Philips). The PETRA-MRA images were compared with those from DSA and TOF-MRA to validate the aneurysm occlusion status and visually assess the blood flow within the stent. Four independent specialists graded occlusion status and flow visualization through the stent using a four-point scale, where 4 points represented excellent visualization of flow within the stent. RESULTS: The aneurysm was located in the internal carotid artery in two patients, the middle cerebral artery in two patients, the top of the basilar artery in one patient, and the vertebral artery-posterior inferior cerebellar artery (VA-PICA) in one patient. Three patients were treated using a Neuroform Atlas Stent system, one using an Enterprise2 VRD, one using two Neuroform Atlas stents for Y-stenting, and the remaining patient using a Neuroform Atlas and an Enterprise2 VRD for Y-stenting. With DSA, the postoperative aneurysm occlusion status was neck remnant (NR) in five cases and complete obliteration (CO) in one case. DSA and PETRA-MRA evaluations demonstrated an equal occlusion status in five of six cases, whereas DSA and TOF-MRA were equal in two of six cases. The mean visualization score for PETRA-MRA was 3.33 ± 0.82, whereas that for TOF-MRA was 2.17 ± 1.33. On the PETRA-MRA images, blood flow through the stent was well-visualized and produced an aneurysm occlusion status score comparable to DSA, especially in the three cases using the Neuroform Atlas Stent System where the visualization was scored 4 points. In the case of the VA-PICA aneurysm, for which an Enterprise2 VRD was used, PETRA-MRA images were insufficient for postoperative assessment. CONCLUSION: PETRA-MRA can provide good visualization of the blood flow within a stent and displays a clear blood signal near the coils, barring small magnetic susceptibility artifacts. Therefore, PETRA-MRA may be an effective option for follow-up imaging after stent-assisted coil embolization.
目的:使用磁共振血管造影(MRA)的径向采集逐点编码时间减少(PETRA)是一种采用超短回波时间的非增强MRA技术,已知在栓塞后成像期间可显著降低线圈和支架的磁敏感性。我们评估了PETRA-MRA图像在用于治疗动脉瘤的支架辅助线圈栓塞手术的随访评估中的质量。 方法:总共纳入了6例接受支架辅助线圈栓塞治疗的动脉瘤患者。所有患者均接受了PETRA-MRA、使用MAGNETOM Skyra(西门子)进行的飞行时间(TOF)-MRA以及使用Infinix Celeve-i INFX-8000V(佳能医疗系统)和Allura Clarity FD20/15(飞利浦)进行的数字减影血管造影(DSA)。将PETRA-MRA图像与DSA和TOF-MRA的图像进行比较,以验证动脉瘤闭塞状态并直观评估支架内的血流。四名独立专家使用四点量表对支架内的闭塞状态和血流可视化进行评分,其中4分表示支架内血流可视化极佳。 结果:2例患者的动脉瘤位于颈内动脉,2例位于大脑中动脉,1例位于基底动脉顶端,1例位于椎动脉-小脑后下动脉(VA-PICA)。3例患者使用Neuroform Atlas支架系统进行治疗,1例使用Enterprise2 VRD,1例使用两个Neuroform Atlas支架进行Y形支架置入,其余患者使用一个Neuroform Atlas和一个Enterprise2 VRD进行Y形支架置入。DSA显示,术后动脉瘤闭塞状态为5例颈部残留(NR),1例完全闭塞(CO)。DSA和PETRA-MRA评估在6例中的5例显示闭塞状态相同,而DSA和TOF-MRA在6例中的2例相同。PETRA-MRA的平均可视化评分为3.33±0.82,而TOF-MRA为2.17±1.33。在PETRA-MRA图像上,支架内的血流清晰可见,产生的动脉瘤闭塞状态评分与DSA相当,特别是在使用Neuroform Atlas支架系统的3例中,可视化评分为4分。在使用Enterprise2 VRD的VA-PICA动脉瘤病例中,则PETRA-MRA图像不足以进行术后评估。 结论:PETRA-MRA可以很好地显示支架内的血流,并在靠近线圈处显示清晰的血流信号,除了小的磁敏感性伪影。因此,PETRA-MRA可能是支架辅助线圈栓塞术后随访成像的有效选择。
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