Role of shear stress in the blister formation of cerebral aneurysms.
BACKGROUND
The development of cerebral aneurysms is related to hemodynamic stress.


OBJECTIVE
To elucidate the role of shear stress in the blister formation of cerebral aneurysms.


METHODS
Among 82 aneurysms detected during catheter-based 3D rotational angiography (3DRA), 4 aneurysms enlarged with blister formation during a mean follow-up period of 10.1 month. Three of these 4 aneurysms were analyzed in this study. The regions of blister formation were characterized by comparing 3DRA before and after blister formation, and computational fluid dynamic simulations were performed based on the aneurysm geometry before blister formation.


RESULTS
The spatially averaged shear magnitude was lower in the aneurysm region (0.97 ± 0.39 Pa) than in the parent artery (2.75 ± 0.92 Pa). The spatially averaged shear magnitude of the blister-forming area was extremely low (0.48 ± 0.12 Pa), and the shear magnitude dropped precipitately to subphysiological levels, resulting in a high shear gradient near the border of the blister-forming area.


CONCLUSIONS
These data suggest that low shear magnitude may trigger the progression of cerebral aneurysms and that blister formation is associated with high shear gradient in the large region of low shear magnitude on the aneurysm wall.
Department of Neurosurgery, The University of Tokyo, Tokyo, Japan. mshoji-tky@umin.ac.jp
Masaaki
M
Shojima
Shigeru
S
Nemoto
Akio
A
Morita
Marie
M
Oshima
Eiju
E
Watanabe
Nobuhito
N
Saito
D001768:Blister / Q000000981:diagnostic imaging* / Q000209:etiology / Q000503:physiopathology*; D002533:Cerebral Angiography / Q000379:methods*; D005260:Female; D006801:Humans; D002532:Intracranial Aneurysm / Q000150:complications / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D033081:Shear Strength