Serial Imaging Surveillance for Patients With a History of Intracranial Aneurysm: Risk of De Novo Aneurysm Formation

BACKGROUND:Although rare, de novo intracranial aneurysms (DNIAs) may develop in patients with a history of intracranial aneurysms (IAs).OBJECTIVE:To evaluate the benefit of routine radiographic screening for DNIAs.METHODS:Data for 2153 patients with IAs were retrospectively analyzed. A total of 185 patients underwent screening for DNIAs at frequent intervals.RESULTS:Overall, DNIAs were detected in 26 patients (1.2%). Of the 185 patients with surveillance, DNIAs developed in 9 (4.9%). The risk of DNIA detection was 1.14% per person-year of follow-up (95% confidence interval: 0.6%-2.2%). Patients with imaging follow-up had a significantly higher rate of DNIA detection compared with patients without regular imaging surveillance (4.9% vs 0.86%; P < .001), but surveillance was associated with smaller lesions (with surveillance: 3.8 1.8 mm, without: 7.0 4.4 mm, mean standard deviation; P = .026). A unimodal distribution of time to detection was found in those with surveillance, with a peak between 0 and 2 years. There was a trend toward an association of cigarette smoking and DNIA detection within 10 years (P = .06); 6 of the 26 patients (23.1%) with DNIAs had a history of cigarette smoking, with all 6 patients continuing to smoke up to the detection of the DNIAs, which were detected in 2.5 1.8 years.CONCLUSION:The low 1.14% per-person year risk of DNIA detection and small DNIA size at detection cannot justify routine screening for DNIAs in all patients with a personal history of IAs. If imaging follow-up is considered for selected patients, early screening will likely yield the most benefit in patients who continue to smoke cigarettes.ABBREVIATIONS:CTA, computed tomography angiographyDNIA, de novo intracranial aneurysmDSA, digital subtraction angiographyIA, intracranial aneurysmMRA, magnetic resonance angiographySAH, subarachnoid hemorrhage