Heldring Nina, Larsson André, Rezaie Ali-Reza, Råsten-Almqvist Petra, Zilg Brita
Department of Forensic Medicine, Swedish National Board of Forensic Medicine, Retzius väg 5, SE-171 65 Stockholm, Sweden.
Forensic Sci Int. 2022 Jan;330:111108. doi: 10.1016/j.forsciint.2021.111108. Epub 2021 Nov 19.
This study aims to generate a statistical model based on magnetic resonance imaging of the knee and radiography of third molars in the lower jaw, for assessing age relative to the 18-year old threshold.
In total, 58 studies correlating knee or tooth development to age were assessed, 5 studies for knee and 7 studies for tooth were included in the statistical model. The relation between the development of the anatomical site, based on a binary system, and age were estimated using logistic regression. Separate meta-populations for knee and tooth were generated from the individual based data for men and women. A weighted estimate of probabilities was made by combining the probability densities for knee and tooth. Margin of errors for males and females in different age groups and knee and tooth maturity were calculated within the larger framework of transition analysis using a logit model as a base. Evidentiary values for combinations of knee and tooth maturity were evaluated with likelihood ratios.
For males, the sensitivity for the method was calculated to 0.78 (probability of correctly classifying adults), the specificity 0.90 (probability of correctly classifying minors), the negative predictive value 0.80 (proportion identified minors are minors) and the positive predictive value 0.89 (proportion identified adults are adults) indicating a model better at identifying minors than adults. The point at which half the female population has reached closed knee lies before the 18-year threshold, adding the knee as an indicator lowers specificity and increases sensitivity. The sensitivity when using tooth as an indicator for females is 0.24 and specificity 0.97, signifying few minors misclassified as adults but also a low probability of identifying adults. The negative predictive value for women when using tooth as the sole indicator is 0.56 and positive predictive value 0.88. Probabilities were calculated for males and females assuming a uniform age distribution between 15 and 21years. The calculated margin of error of minors classified as adults in a population between 15 and 21 years with the model was 11% for males and 12% for females. Further, the evidentiary value as well as margin of error vary for different combinations of knee and tooth maturity.
The statistical model based on the combination of MRI knee and radiography of mandibular third molars is a valid method to assess age relative to the 18-year old threshold when applied on males and of limited value in females.
本研究旨在基于膝关节磁共振成像和下颌第三磨牙X线摄影生成一个统计模型，用于评估相对于18岁阈值的年龄。
总共评估了58项将膝关节或牙齿发育与年龄相关联的研究，统计模型纳入了5项关于膝关节的研究和7项关于牙齿的研究。基于二元系统的解剖部位发育与年龄之间的关系采用逻辑回归进行估计。从男性和女性的个体数据中生成膝关节和牙齿的单独元群体。通过合并膝关节和牙齿的概率密度对概率进行加权估计。在以logit模型为基础的转换分析的更大框架内，计算不同年龄组以及膝关节和牙齿成熟度的男性和女性的误差范围。用似然比评估膝关节和牙齿成熟度组合的证据价值。
对于男性，该方法的敏感性计算为0.78（正确分类成年人的概率），特异性为0.90（正确分类未成年人的概率），阴性预测值为0.80（被识别为未成年人的比例是未成年人），阳性预测值为0.89（被识别为成年人的比例是成年人），表明该模型在识别未成年人方面比成年人更好。一半女性人群达到膝关节闭合的时间点在18岁阈值之前，将膝关节作为一个指标会降低特异性并提高敏感性。女性使用牙齿作为指标时的敏感性为0.24，特异性为0.97，这意味着很少有未成年人被误分类为成年人，但识别成年人的概率也很低。女性仅使用牙齿作为指标时的阴性预测值为0.56，阳性预测值为0.88。假设年龄在15至21岁之间均匀分布，计算了男性和女性的概率。使用该模型在15至21岁人群中被分类为成年人的未成年人的计算误差范围，男性为11%，女性为12%。此外，膝关节和牙齿成熟度的不同组合的证据价值以及误差范围也有所不同。
基于膝关节磁共振成像和下颌第三磨牙X线摄影相结合的统计模型，应用于男性时是评估相对于18岁阈值年龄的有效方法，而对女性的价值有限。
