Hemodynamic characteristics associated with thinner regions of intracranial aneurysm wall

Abstract Aneurysm wall thickness is an important determinant of aneurysm progression and intra-procedural rupture. Several previous studies have evaluated the association between hemodynamic stress and aneurysm wall thickness, but conflicting results were obtained and no consensus has been achieved. According to the intraoperative findings, twenty-eight unruptured middle cerebral artery (MCA) aneurysms presented with thin-walled regions were enrolled in our study. Patient-specific 3D aneurysm models were constructed from preoperative computed tomography angiography (CTA) data and computational fluid dynamics (CFD) analyses were performed under pulsatile-flow conditions. Thin-walled regions of aneurysm dome were recognized by two experienced reviewers based on the intraoperative microscopy findings. Hemodynamic parameters derived from CFD analysis, including normalized wall shear stress (NWSS), normalized pressure (NP), the oscillatory shear index (OSI) and relative residence time (RRT), were compared between thin-walled regions and surrounding normal-thickness areas. Of the included aneurysms, twenty-eight pairs of thin-walled and normal surrounding regions were determined. Compared with surrounding tissues, thin-walled regions of aneurysm wall tended to present with higher pressure (1.232 vs 1.043, p