Objectives Providing recommendations for wrist MRI in age estimation by determining (1) which anatomical structures to include in the statistical model, (2) which MRI sequence to conduct, and (3) which staging technique to apply. Methods Radius and ulna were prospectively studied on 3T MRI in 363 healthy Caucasian participants (185 females, 178 males) between 14 and 26 years old, using T1 spin echo (SE) and T1 gradient echo VIBE. Bone development was assessed applying a 5-stage staging technique with several amelioration attempts to optimise staging. A Bayesian model rendered point predictions of age and diagnostic indices to discern minors from adults. Results All approaches rendered similar results, with none of them outperforming the others. A single bone assessment of radius or ulna sufficed. SE and VIBE sequences were both suitable, but needed sequence-specific age estimation. A one-fits-all 5-stage staging technique-with substages in stage 3was suitable and did not benefit from profound substaging. Age estimation based on SE radius resulted in a mean absolute error of 1.79 years, a specificity (correctly identified minors) of 93%, and a discrimination slope of 0.640. Conclusion Radius and ulna perform similarly to estimate age, and so do SE and VIBE. A one-fits-all staging technique can be applied.

Background MRI of the clavicle's sternal end has been studied for age estimation. Several pitfalls have been noted, but how they affect age estimation performance remains unclear. Purpose/Hypothesis To further study these pitfalls and to make suggestions for a proper use of clavicle MRI for forensic age estimation. Our hypotheses were that age estimation would benefit from 1) discarding stages 1 and 4/5; 2) including advanced substages 3aa, 3ab, and 3ac; 3) taking both clavicles into account; and 4) excluding morphological variants. Study Type Prospective cross‐sectional. Population Healthy Caucasian volunteers between 11 and 30 years old (524; 277 females, 247 males). Field Strength/Sequence 3T, T1‐weighted gradient echo volumetric interpolated breath‐hold examination (VIBE) MR‐sequence. Assessment Four observers applied the most elaborate staging technique for long bone development that has been described in the current literature (including stages, substages, and advanced substages). One of the observers repeated a random selection of the assessments in 110 participants after a 2‐week interval. Furthermore, all observers documented morphological variants. Statistical Tests Weighted kappa quantified reproducibility of staging. Bayes' rule was applied for age estimation with a continuation ratio model for the distribution of the stages. According to the hypotheses, different models were tested. Mean absolute error (MAE) differences between models were compared, as were MAEs between cases with and without morphological variants. Results Weighted kappa equaled 0.82 for intraobserver and ranged between 0.60 and 0.64 for interobserver agreement. Stages 1 and 4/5 were allocated interchangeably in 4.3% (54/1258). Age increased steadily in advanced substages of stage 3, but improvement in age estimation was not significant (right P = 0.596; left P = 0.313). The model that included both clavicles and discarded stages 1 and 4/5 yielded an MAE of 1.97 years, a root mean squared error of 2.60 years, and 69% correctly classified minors. Morphological variants rendered significantly higher MAEs (right 3.84 years, P = 0.015; left 2.93 years, P = 0.022). Data Conclusion Our results confirmed hypotheses 3) and 4), while hypotheses 1) and 2) remain to be investigated in larger studies. Level of Evidence: 1 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2020;51:377–388.

To study age estimation performance of combined magnetic resonance imaging (MRI) data of all four third molars, the left wrist and both clavicles in a reference population of females and males. To study the value of adding anthropometric and sexual maturation data.Materials and methods: Three Tesla MRI of the three anatomical sites was prospectively conducted from March 2012 to May 2017 in 14-to 26-year-old healthy Caucasian volunteers (160 females, 138 males). Development was assessed by allocating stages, anthropometric measurements were taken, and self-reported sexual maturation data were collected. All data was incorporated in a continuationratio model to estimate age, applying Bayes' rule to calculate point and interval predictions. Two performance aspects were studied: (1) accuracy and uncertainty of the point prediction, and (2) diagnostic ability to discern minors from adults (≥ 18 years).Results: Combining information from different anatomical sites decreased the mean absolute error (MAE) compared to incorporating only one site (P < 0.0001). By contrast, adding anthropometric and sexual maturation data did not further improve MAE (P = 0.11). In females, combining all three anatomical sites rendered a MAE equal to 1.41 years, a mean width of the 95% prediction intervals of 5.91 years, 93% correctly classified adults and 91% correctly classified minors. In males, the corresponding results were 1.36 years, 5.49 years, 94%, and 90%, respectively. Conclusion:All aspects of age estimation improve when multi-factorial MRI data of the three anatomical sites are incorporated. Anthropometric and sexual maturation data do not seem to add relevant information.

Purpose: To determine how motion affects stage allocation to the clavicle's sternal end on MRI. Materials and methods: Eighteen volunteers (9 females, 9 males) between 14 and 30 years old were prospectively scanned with 3T MRI. One resting state scan was followed by five intentional motion scans. Additionally, a control group of 72 resting state scans were selected from previous research. Firstly, six observers allocated developmental stages to the clavicles independently. Secondly, they reassessed the images, allocating developmental statuses (immature, mature). Finally, the resting state scans of the 18 volunteers were assessed in consensus to decide on the 'correct' stage/status. Results were compared between groups (control, prospective resting state, prospective motion), and between staging techniques (stages/statuses). Results: Inter-observer agreement was low (Krippendorf α 0.23-0.67). The proportion of correctly allocated stages (64%) was lower than correctly allocated statuses (83%). Overall, intentional motion resulted in fewer assessable images and less images of sufficient evidential value. The proportion of correctly allocated stages did not differ between resting state (64%) and motion scans (65%), while correctly allocated statuses were more prevalent in resting state scans (83% versus 77%). Remarkably, motion scans did not render a systematically higher or lower stage/status, compared to the consensus. Conclusion: Intentional motion impedes clavicle MRI for age estimation. Still, in case of obvious disturbances, the forensic expert will consider the MRI unsuitable as evidence. Thus, the development of the clavicle as such and the staging technique seem to play a more important role in allocating a faulty stage for age estimation.

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