Introduction: Intracranial aneurysms, especially small and asymptomatic ones, are often monitored with imaging studies. However, the prognosis of aneurysms varies according to many factors, which is reflected in variation in growth.
Hypothesis: A time course analysis with a long follow up period can reveal characteristics of aneurysm growth and factors related to growth.
Methods: All patients who underwent two CTA, including one in 2015, were reviewed. Intracranial saccular aneurysms were selected and fusiform, dissecting and mycotic aneurysms were excluded. Aneurysm characteristics, patient information, and medical history were recorded. Growth was defined as more than a 0.5 mm size increase compared with the first study. Log-rank and Cox regression tests were applied to identify factors related growth.
Results: This study included 119 aneurysms of 91 patients that underwent a total of 474 CTA, with initial size 0.0-17.0 mm and follow-up duration of 42.9 ± 44.8 months. Eighteen aneurysms increased in size. Follow-up period to growth was 25.4 ± 20.8 months. Growth rate was highly variable (0.74 ± 3.23 mm/year). On univariate log-rank or Cox regression test, only history of transient ischemic attack (TIA) (P = 0.016) showed significance for aneurysm growth. On multivariate Cox regression test, history of TIA (P = 0.010, hazard ratio = 7.939), the maximum diameter at the first CTA (P = 0.026, hazard ratio = 1.216) and history of cancer (P = 0.028, hazard ratio = 4.499). Cancers existed in breast, thyroid, and lung.
Conclusions: Aneurysm growth rate can vary even in the same patient. Aneurysm growth frequency varied according to size and risk factors. History of cancer has not previously been associated with aneurysm growth and may benefit from further study.