Comparison of ELAPSS Score and Computational Fluid Dynamics for Predicting Growth of Small Unruptured Cerebral Aneurysms

ELAPSS score is commonly utilized for predicting the growth of unruptured cerebral aneurysms. However, its application is unsuitable for small aneurysms with high demand for growth prediction. Consequently, we investigated the diagnostic accuracy of semi-quantitative assessment using the ELAPSS score and hemodynamic parameters using computational fluid dynamics in small aneurysms. A prospective observational study from January 2013 to February 2022 included 185 patients with 215 unruptured aneurysms with a maximum diameter of 3-5 mm. Aneurysms were classified into stable (186 aneurysms) and growth (29 aneurysms) groups based on repeated images. We calculated high shear area ratios, high shear concentration ratios, and flow concentration ratios as hemodynamic parameters that we have already reported to be associated with small aneurysm growth in our previous study. The characteristics associated with the growth of small aneurysms were statistically investigated with morphological variables and hemodynamic parameters. The ELAPSS score was also calculated for the same aneurysm group to determine whether the growth risk was sufficiently assessed. In morphological variables, no significant differences were observed between the 2 groups. As for the hemodynamic parameters, the growth group had a significantly lower flow concentration ratio (0.61 vs 0.66, p = 0.016), lower high shear area ratio (0.28 vs 0.33, p < 0.001), and a higher high shear concentration ratio (6.39 vs 5.01, p < 0.001). However, there were no significant differences in the ELAPSS scores between the 2 groups. When limited to small aneurysms, computational fluid dynamics may offer more enhanced predictive capabilities compared to the ELAPSS score for identifying growth tendencies.