Forensic age estimation in the living by 0.31 Tesla low-field MRI of the distal radius

OBJECTIVES: Examination of the radius' distal epiphysis by means of low-field MRI in order to find a reliable method to correctly assess majority in both sexes. MATERIALS & METHODS: 650 volunteers of German nationality, evenly distributed to groups of 25 per sex and years of proven age in the age bracket of 12-24 years, were examined between 2021 and 2023 in a single center, prospective, cross-sectional setting. A 0.31 T dedicated joint scanner was used, acquiring a proton density-weighted (PDw) sequence in Dixon technique (Dixon) in coronal slice orientation yielding a fat-sensitive water-suppressed (fat-only) and a water-sensitive fat-suppressed (water-only) series. A classification was formulated for assessment and tested against the proven age. The relevant statistics were defined, the intra- and interobserver-agreements were determined, and the differences between the sexes were analyzed. RESULTS: The minimum age for stage 6 of the classification was found to be 18.42 years in male individuals and 17.25 years in female individuals. A Mann-Whitney-U Test implies significant sex-related differences for stage 3 (p < 0.01) and stage 4 (p < 0.01), but not for stage 2 (p < 0.162), stage 5 (p < 0.193) and stage 6 (p < 0.146). The intra- and interobserver-agreement levels were substantial. CONCLUSION: When using the presented setting of a low-field 0.31 T dedicated joint scanner, acquiring PDw Dixon fat-only and water-only series of the radius' distal epiphysis and using the presented classification, majority can be determined in male but not in female individuals of our cohort. Therefore, 0.31 T low-field MRI yields similar opportunities as examinations by means of high-field MRI scanners.