Abstract
BACKGROUND: The yield of whole-body MRI for preventive health screening is currently not completely clear. PURPOSE: To systematically review the prevalence of whole-body MRI findings in asymptomatic subjects. STUDY TYPE: Systematic review and meta-analysis. SUBJECTS: MEDLINE and Embase were searched for original studies reporting whole-body MRI findings in asymptomatic adults without known disease, syndrome, or genetic mutation. Twelve studies, comprising 5373 asymptomatic subjects, were included. FIELD STRENGTH/SEQUENCE: 1.5T or 3.0T, whole-body MRI. ASSESSMENT: The whole-body MRI literature findings were extracted and reviewed by two radiologists in consensus for designation as either critical or indeterminate incidental finding. STATISTICAL TESTS: Data were pooled using a random effects model on the assumption that most subjects had ≤1 critical or indeterminate incidental finding. Heterogeneity was assessed by the I(2) statistic. RESULTS: Pooled prevalences of critical and indeterminate incidental findings together and separately were 32.1% (95% confidence interval [CI]: 18.3%, 50.1%), 13.4% (95% CI: 9.0%, 19.5%), and 13.9% (95% CI: 5.4%, 31.3%), respectively. There was substantial between-study heterogeneity (I(2) = 95.6-99.1). Pooled prevalence of critical and indeterminate incidental findings together was significantly higher in studies that included (cardio)vascular and/or colon MRI compared with studies that did not (49.7% [95% CI, 26.7%, 72.9%] vs. 23.0% [95% CI, 5.5%, 60.3%], P < 0.001). Pooled proportion of reported verified critical and indeterminate incidental findings was 12.6% (95% CI: 3.2%, 38.8%). Six studies reported false-positive findings, yielding a pooled proportion of 16.0% (95% CI: 1.9%, 65.8%). None of the included studies reported long-term (>5-year) verification of negative findings. Only one study reported false-negative findings, with a proportion of 2.0%. DATA CONCLUSION: Prevalence of critical and indeterminate incidental whole-body MRI findings in asymptomatic subjects is overall substantial and with variability dependent to some degree on the protocol. Verification data are lacking. The proportion of false-positive findings appears to be substantial. LEVEL OF EVIDENCE: 4 Technical Efficacy: Stage 3 J. Magn. Reson. Imaging 2019;50:1489-1503.