Characteristics of the aneurysms (n = 4813)
| Characteristics | Radiation-Related Group | Control Group | P Value |
|---|---|---|---|
| Aneurysm size (mean) (mm) | 4.9 (SD, 2.3) | 5.2 (SD, 2.2) | NS |
| Location of aneurysm (No.) (%) | .046 | ||
| ICA | 23 (53.5) | 2015 (42.2) | |
| Anterior cerebral artery | 6 (14.0) | 1213 (25.4) | |
| MCA | 6 (14.0) | 1066 (22.3) | |
| Posterior circulation artery | 8 (18.6) | 476 (10.0) | |
| Type of aneurysm (No.) (%) | .048 | ||
| Sidewall | 20 (46.5) | 1543 (32.3) | |
| Bifurcation | 23 (53.5) | 3227 (67.7) | |
| Irregular wall | 12 (27.9) | 1438 (30.1) | NS |