• aneurysm
• technology

People have mused that fusion as a source of energy is ‘30 years away and always will be’. Similarly, the application of computational fluid dynamics (CFD) to solve problems in medicine, and in particular neurovascular disease, has been ongoing for decades, but still has yet to inform clinical decision-making. Within the neurointerventional community, CFD is often applied to investigate cerebral aneurysm formation, growth, rupture risk and treatment response.1–3 However, the lack of routine clinical application likely stems from the heterogeneity of scientific approaches, inconsistent rigor, lack of physiological boundary conditions, and a predilection to report novelty over statistical significance (such as a ‘new’ variable correlating with outcome).4 5 Over the last year, this journal has published a wide variety of CFD studies,6–14 several of which hopefully get us closer to clinical utilization of CFD.

Aneurysm irregularity, in particular ‘blebs’ or daughter sacs, are considered clinically relevant in increasing the risk of aneurysm rupture.15 Two studies considered the hemodynamic underpinnings of aneurysmal blebs. The first12 studied what hemodynamic conditions may lead to bleb formation. Of 270 aneurysms studied, 97 had 122 blebs. CFD simulations were performed on each irregularly-shaped aneurysm with the bleb artificially ‘removed’ from the simulation’s anatomy, and the resultant hemodynamics were compared with those aneurysms with a more regular dome geometry. Bleb-removed aneurysms showed consistent and significant morphometric and hemodynamic differences, including larger size, wider neck, more surface irregularities, increased aneurysm inflow and intra-aneurysmal flow velocity, complex flow patterns, higher wall shear stress …