Pereira Vitor Mendes, Brina Olivier, Delattre Benedicte M A, Ouared Rafik, Bouillot Pierre, Erceg Gorislav, Schaller Karl, Lovblad Karl-Olof, Vargas Maria-Isabel
Division of Neuroradiology, Department of Medical Imaging, University Hospitals of Geneva, Geneva, Switzerland Division of Neuroradiology, Department of Medical Imaging, Toronto Western Hospital, University Health Network, Toronto, Ontario, Canada Division of Neurosurgery, Department of Surgery, Toronto Western Hospital, University Health Network, Toronto, Ontario, Canada.
Division of Neuroradiology, Department of Medical Imaging, University Hospitals of Geneva, Geneva, Switzerland.
J Neurointerv Surg. 2015 Dec;7(12):913-9. doi: 10.1136/neurintsurg-2014-011348. Epub 2014 Oct 3.
Flow diverter stents (FDS) have been effectively used for the endovascular treatment of sidewall intracranial aneurysms (IAs). Unlike standard endovascular treatments used to exclude directly the aneurysm bulge from the parent vessel, FDS induce reduction in the intra-aneurysmal flow and promote progressive and stable thrombosis therein. The advent of FDS has therefore increased the need for understanding of IA hemodynamics.
We proposed the use of the most recently evolved four-dimensional (4D) flow MRI technique to evaluate qualitatively and quantitatively post-FDS flow modification in 10 patients. We report intra-aneurysmal velocity measurements and the influence of metal artifacts induced by the stent.
An index was defined to quantitatively measure flow changes-namely, the proportional velocity reduction ratio (PVRR)-with ranges from 34.6% to 71.1%. Furthermore, we could compare streamlines characterizing the post-stent flow patterns in five patients in whom the intra-aneurysmal velocity was beyond the visualization threshold of 7.69 cm/s.
Despite metal artifacts and the low velocities involved, 4D flow MRI could be of interest to measure qualitatively and quantitatively flow changes in stented aneurysms. However, further enhancements are required together with further validation work before it can be considered for clinical use.
血流导向支架（FDS）已有效地用于颅内侧壁动脉瘤（IA）的血管内治疗。与用于直接将动脉瘤瘤体与母血管隔绝的标准血管内治疗不同，FDS可减少动脉瘤内的血流，并促进瘤内血栓形成的进展和稳定。因此，FDS的出现增加了对IA血流动力学理解的需求。
我们建议使用最新发展的四维（4D）血流磁共振成像（MRI）技术，对10例患者FDS置入后的血流改变进行定性和定量评估。我们报告动脉瘤内速度测量结果以及支架引起的金属伪影的影响。
定义了一个指数来定量测量血流变化，即比例速度降低率（PVRR），范围为34.6%至71.1%。此外，我们可以比较5例动脉瘤内速度超过7.69 cm/s可视化阈值患者的支架置入后血流模式的流线。
尽管存在金属伪影且涉及的速度较低，但4D血流MRI在定性和定量测量支架置入后动脉瘤的血流变化方面可能具有价值。然而，在考虑将其用于临床之前，还需要进一步改进并开展进一步的验证工作。
