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Castle-Kirszbaum M, Maingard J, Lim RP, Barras CD, Kok HK, Chandra RV, Chong W, Asadi H. Four-Dimensional Magnetic Resonance Imaging Assessment of Intracranial Aneurysms: A State-of-the-Art Review. Neurosurgery 2020; 87:453-465. [PMID: 32140714 DOI: 10.1093/neuros/nyaa021] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2019] [Accepted: 12/15/2019] [Indexed: 11/14/2022] Open
Abstract
Treatment of unruptured intracranial aneurysms can reduce the risk of subarachnoid hemorrhage and its associated morbidity and mortality. However, current methods to predict the risk of rupture and optimize treatment strategies for intracranial aneurysms are limited. Assessment of intra-aneurysmal flow using 4-dimensional magnetic resonance imaging (4D MRI) is a novel tool that could be used to guide therapy. A systematic search of the literature was performed to provide a state-of-the-art review on 4D MRI assessment of unruptured intracranial aneurysms. A total of 18 studies were available for review. Eccentric flow on 4D MRI is associated with a greater aspect ratio and peak wall shear stress (WSS). WSS, vorticity, and peak velocity are greater in saccular than fusiform aneurysms. Unstable aneurysms are associated with greater WSS, peak wall stress, and flow jet angle and may exhibit wall enhancement. In comparison to computational fluid dynamics (CFD), 4D MRI has a lower spatial resolution and reports lower WSS and velocity magnitudes, but these parameters equalize when spatial resolution is matched. 4D MRI demonstrates the intra-aneurysmal hemodynamic changes associated with flow diversion, including significantly decreased flow velocity. Thus, 4D MRI is a novel, noninvasive imaging tool used for the evaluation of hemodynamics within intracranial aneurysms. Hemodynamic indices derived from 4D MRI appear to correlate well with the simulated (CFD) values and may be used to measure the success of endovascular therapies and risk factors for aneurysm growth and rupture.
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Affiliation(s)
- Mendel Castle-Kirszbaum
- NeuroInterventional Radiology Unit, Monash Health, Melbourne, Australia.,Department of Neurosurgery, Monash Health, Melbourne, Australia
| | - Julian Maingard
- NeuroInterventional Radiology Unit, Monash Health, Melbourne, Australia.,Department of Imaging, Monash Health, Melbourne, Australia.,School of Medicine, Deakin University, Victoria, Australia
| | - Ruth P Lim
- Austin Health, Melbourne, Australia.,The University of Melbourne, Melbourne, Australia
| | - Christen D Barras
- Department of Radiology, Royal Adelaide Hospital, The University of Adelaide, Australia.,South Australian Health and Medical Research Institute, Adelaide, Australia
| | - Hong Kuan Kok
- School of Medicine, Deakin University, Victoria, Australia.,Department of Radiology Northern Health, Melbourne, Australia
| | - Ronil V Chandra
- NeuroInterventional Radiology Unit, Monash Health, Melbourne, Australia.,Department of Imaging, Monash Health, Melbourne, Australia.,Monash University, Melbourne, Australia
| | - Winston Chong
- NeuroInterventional Radiology Unit, Monash Health, Melbourne, Australia.,Department of Imaging, Monash Health, Melbourne, Australia.,Monash University, Melbourne, Australia
| | - Hamed Asadi
- NeuroInterventional Radiology Unit, Monash Health, Melbourne, Australia.,Department of Imaging, Monash Health, Melbourne, Australia.,School of Medicine, Deakin University, Victoria, Australia.,Austin Health, Melbourne, Australia
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