Incidental findings on brain magnetic resonance imaging in the elderly:the PROOF study.

To prospectively evaluate the prevalence of incidental findings on standardized brain MRI scans in a cohort of elderly subjects. All participants provided written informed consent to participate in this prospective study, which was approved by the institutional review board and was HIPAA compliant. There were 503 subjects (75.3 ± 0.9 years of age, 58 % women) who received brain MRIs on a 1.5-T scanner using a standard acquisition protocol. All scans were reviewed by an experienced neuroradiologist. Incidental findings were stratified as follows: 1, no incidental findings; 2, incidental findings without clinical significance; 3, incidental findings with clinical significance or requiring clinical follow-up. Incidental findings were identified in 77.9 % of subjects. Among 392 scans that exhibited incidental findings, 494 abnormalities were identified. The most common findings in our study were cysts (45.9 % of subjects) and ear, nose, and throat (ENT) lesions (24.8 %) followed by stroke lesions (6.6 %) and neoplasms (3.8 %). There were 472 incidental findings that lacked clinical significance (group 2), and 22 incidental findings that required follow-up evaluation (group 3). Incidental findings on brain MRIs were commonly observed in this cohort of elderly subjects, but clinical follow-up was rarely indicated.