Whole-body MRI for preventive health screening in a general population: Prevalence of incidental findings around the hip

Purpose: To report the frequencies of incidental findings on whole body MRI (WB-MRI) around the hip and to characterize the significance of incidental findings in a general population. Materials and methods: This retrospective study included 7287 cases that underwent WB-MRI as part of a preventive health screening. WB-MR images were reviewed by two musculoskeletal radiologists in consensus. According to clinical severity and urgency of medical intervention, each finding was classified into two subgroups as clinically significant and insignificant. The clinically significant group included findings that suggested abnormalities requiring further evaluation or follow-up, such as avascular necrosis (AVN), bone tumor (enchondroma), soft tissue tumor, and fracture. The clinically less significant group included subcortical cyst, bone marrow edema, para-labral cyst, simple bone cysts, and ganglion cysts. Results: The prevalence of clinically significant and less significant incidental findings of the hip on WB-MRI was substantial overall. The incidences were recorded as 1.2% and 19.9%, respectively. Besides bone and soft tissue tumor or tumor-like lesions, AVN of the femoral head was one of the findings with a 0.3% prevalence. Conclusions: An awareness of the prevalence of incidental findings can be helpful for radiologists and clinicians when interpreting WB-MRI for health screening and explaining the results to subjects.