With the widespread use of imaging techniques, the possibility that an asymptomatic unruptured intracranial aneurysm (UIA) is detected has increased significantly. There is no established consensus regarding follow-up, duration, and frequency of such imaging surveillance. The objectives of this study include assessing the growth rate and rupture risk of small (less than 7mm) UIAs, identifying associated risk factors and providing an aneurysm surveillance protocol in appropriately selected patients. Systematic searches of Medline, Embase, and Cochrane Central were undertaken from database inception to March 2020 for published studies reporting the growth and rupture risks of small UIAs. Twenty-one studies reporting 8428 small UIAs were included in our meta-analysis. The pooled mean age was 61 years (95% CI: 55–67). The mean follow-up period for growth and rupture ranged from 11 to 108 months, with the pooled mean follow-up period across 14 studies being 42 months (95% CI: 33–51). Pooled overall growth rate was 6.0% (95% CI: 3.8–8.7). Pooled growth rates for aneurysms < 5mm and < 3 mm were 5.2% (95% CI: 3.0–7.9) and 0.8% (95% CI: 0.0–6.1), respectively. Pooled overall rupture rate was 0.4% (95% CI: 0.2–0.7). From the meta-regression analysis, having multiple aneurysms, smoking, hypertension, and personal history of SAH did not significantly predict growth, and a personal history of SAH, smoking, hypertension, and multiple aneurysms were not statistically significant predictors of rupture. Our findings suggest that small UIAs have low growth and rupture rates and very small UIAs have little or no risk for rupture. In the setting of incidental small UIAs, patients with multiple and/or posterior circulation aneurysms require more regular radiological monitoring.

随着成像技术的广泛应用，检测到无症状未破裂颅内动脉瘤（UIA）的可能性显着增加。关于此类影像监测的随访、持续时间和频率，尚未达成共识。The objectives of this study include assessing the growth rate and rupture risk of small (less than 7mm) UIAs, identifying associated risk factors and providing an aneurysm surveillance protocol in appropriately selected patients. 从数据库开始到 2020 年 3 月，对 Medline、Embase 和 Cochrane Central 进行了系统搜索，以获取报告小型 UIAs 增长和破裂风险的已发表研究。我们的荟萃分析包括了 21 项报告 8428 项小型 UIA 的研究。合并的平均年龄为 61 岁（95% CI：55-67）。生长和破裂的平均随访期为 11 至 108 个月，14 项研究的合并平均随访期为 42 个月（95% CI：33-51）。汇总的总体增长率为 6.0%（95% CI：3.8-8.7）。< 5 毫米和 < 3 毫米动脉瘤的合并增长率分别为 5.2%（95% CI：3.0-7.9）和 0.8%（95% CI：0.0-6.1）。汇总的总体破裂率为 0.4%（95% CI：0.2-0.7）。从荟萃回归分析，多发动脉瘤、吸烟、高血压和 SAH 个人史对生长没有显着预测，SAH 个人史、吸烟、高血压和多发性动脉瘤不是破裂的统计学显着预测因子 0%（95% CI：3.8–8.7）。< 5 毫米和 < 3 毫米动脉瘤的合并增长率分别为 5.2%（95% CI：3.0-7.9）和 0.8%（95% CI：0.0-6.1）。汇总的总体破裂率为 0.4%（95% CI：0.2-0.7）。从荟萃回归分析，多发动脉瘤、吸烟、高血压和 SAH 个人史对生长没有显着预测，SAH 个人史、吸烟、高血压和多发性动脉瘤不是破裂的统计学显着预测因子 0%（95% CI：3.8–8.7）。动脉瘤 < 5 毫米和 < 3 毫米的合并增长率分别为 5.2%（95% CI：3.0-7.9）和 0.8%（95% CI：0.0-6.1）。汇总的总体破裂率为 0.4%（95% CI：0.2-0.7）。从荟萃回归分析，多发动脉瘤、吸烟、高血压和 SAH 个人史对生长没有显着预测，SAH 个人史、吸烟、高血压和多发性动脉瘤不是破裂的统计学显着预测因子. 我们的研究结果表明，小型 UIA 的生长和破裂率较低，非常小的 UIA 破裂风险很小或没有。在偶发性小 UIA 的情况下，多发性和/或后循环动脉瘤患者需要更定期的放射学监测。