Investigating the association between chronological age and thyroid cartilage ossification using CT imaging

Background: Thyroid cartilage ossifies through time. In addition to different methods for age estimation, ossified volume can be a valuable index for age estimation. In this study, anthropometric characteristics and ossified volume were measured using CT scan imaging to find potential correlations between measures and age. Methods: In this study, 100 thyroid cartilage of Iranian corpses (60 men and 40 women) were studied. Corpses from Kahrizak hall of Tehran Legal Medicine Organization were included in this study. After obtaining required consent from their family, their thyroid cartilage was separated by an expert, and anthropometric properties of the cartilage were recorded. A 64-slice Siemens CT scan machine was used to measure specimen ossified volume and Hounsfield score by 3D reconstruction of images. Pearson’s correlation test was used to measure the correlation between thyroid calcified volume and chronological age. Repeated measurement ANOVA test was also used to measure the correlation of the ossified volume and Hounsfield score with different age groups. SPSS version 22 was used for statistical analysis, and significance level was set at than 0.05. Results: All thyroid cartilage measures were higher in men than in women, except for thyroid angle, and the differences were statistically significant. Height of the laminae (R=0.23, p=0.023) and depth of the thyroid notch (R=0.198, p=0.049) were correlated with age. Mean ossified volume (6.1±1.7 cc) and Hounsfield score (308.8±53.5 HU) were directly correlated with age (R=0.205; p=0.040 and R=0.219; p=0.029, respectively), but none of these two radiologic parameters were correlated with age groups (p=0.331 and 0.063, respectively). No specific ossification pattern was obtained from CT images in different age groups. Conclusion: A combination of anthropometric measures such as the height of the laminae and depth of the thyroid notch with CT scan imaging measures such as ossified volume and the Hounsfield score are useful to estimate age with low precision. In addition, thyroid cartilage measures are useful for sex determination.