Minimum wall shear stress points and their underlying intra-aneurysmal flow structures of unruptured cerebral aneurysms on 4D flow MRI

Background and purpose: Minimum wall shear stress (Min-WSS) points may be associated with wall instabil-ity of unruptured cerebral aneurysms. We aimed to investigate the relationship between the locations of Min-WSS points and their underlying intra-aneurysmal flow structure patterns in unruptured cerebral aneurysms using four-dimensional (4D) flow magnetic resonance imaging (MRI).Materials and methods: Min-WSS points and the intra-aneurysmal flow structure patterns were identified in 50 unruptured aneurysms by 4D flow MRI.Results: The Min-WSS points were located around a vortex core tip in 31 (62.0%) aneurysms and on an intra-bleb vortex center in 7 (14.0%). Sixteen (32.0%) aneurysms had the Min-WSS points on the aneurysmal apex, and in 24 (48.0%) were on the neck. The Min-WSS values of aneurysms with the Min-WSS points on an intra-bleb flow were significantly lower than those of the other groups (P = 0.030). Aneurysms with the Min-WSS points on the neck had significantly higher Min-WSS values than the other aneurysms (P = 0.008). Conclusions: The location of the Min-WSS point was corresponding to the vortex core or center in 76% of all aneurysms. The underlying intra-aneurysmal flow structure and location of the Min-WSS point affect the Min-WSS value. Further studies are needed to characterize Min-WSS points to identify aneurysms with a higher risk of wall instability. & COPY; 2022 Elsevier Masson SAS. All rights reserved.

Automated summary

This study investigated the relationship between the locations of minimum wall shear stress (Min-WSS) points and their underlying intra-aneurysmal flow structure patterns in unruptured cerebral aneurysms using four-dimensional flow magnetic resonance imaging (MRI). The majority of Min-WSS points were found to be located around a vortex core or center, and different locations had different Min-WSS values. Further research can help identify cerebral aneurysms with a higher risk of wall instability.