ABSTRACT
Objective To assess the value of outflow angle-assisted (OA-assisted) approach in diagnosing and differentiating sidewall cerebral aneurysms (SCAs) with magnetic resonance angiography (MRA). Methods A total of 438 patients with suspected SCAs and other cerebrovascular diseases were separately evaluated by OA-assisted approach MRA and digital subtraction angiography (DSA). An OA of ≥90o was considered to represent SCA. The diagnostic accuracy, sensitivity, and specificity of SCAs with OA assisted approach were evaluated with the number of aneurysms and the size of aneurysms. Results DSA revealed 301 SCAs in 267 patients, and no SCAs was detected in the remaining 171 patients, among them a total of 55 infundibulae were observed in 52 patients. OA-assisted approach MRA revealed 300 SCAs in 267 patients, among which 271 aneurysms in 238 patients had an OA of ≥90o(true positive of 90.3％) and 29 aneurysms in 29 patients had an OA of <90° (false negative of 9.7％). Based on the patient, the number of aneurysms and the size of aneurysms, OA-assisted approach MRA had higher accuracy, sensitivity and specificity in diagnosing SCAs. The OA of all 54 infundibulae observed in 51 patients was <90°(98.2％), and only one infundibula in one patient was ≥90° (false positive). Conclusion MRA with OA-assisted approach has higher accuracy in diagnosing SCAs and in differentiating SCAs with infundibula, therefore, it can substitute DSA for the diagnosis and differentiation of SCAs.