Retrospective observational study of morphometric assessment of Aortic Knob Dimensions and Cardiothoracic Diameter: Insights in relation to age and gender.

Aim of the study: To evaluate the morphometric characteristics of the aortic knob and examine its potential relationship with cardio-thoracic diameter. Additionally, to investigate any correlation between aortic knob measurements and age, and to compare these dimensions between male and female subjects. Material and methods: Following parameters were analysed in the Chest X Ray in DICOM format using Radiant software. Aortic Knob Width, length of Aortic Knob, Curved length of Aortic Knob followed by calculation of Aortic Knob Index. Additionally, Transverse Thoracic Diameter, Cardiac Diameter were measured and Cardio Thoracic Ratio calculated. Results All parameters, except for the Transverse Thoracic Diameter and Cardio-Thoracic Ratio, were found to be higher in females compared to males; however, these differences were not statistically significant.Cardio Thoracic Ratio was more in males than in females and the difference was statistically significant. Aortic Knob width, straight length of aortic knob, curved length of the aortic knob, transverse thoracic diameter and cardiac diameter showed an increase with age which was statistically significant. Maximum values of the Aortic Knob Width and Aortic Knob Index was observed in the age group of 60-69 years. Cardiothoracic Ratio values showed significant decrease with age. The Aortic Knob Width showed strong positive corelation with all parameters except Aortic Knob Index and Cardio Thoracic Ratio. Conclusion: This study provides normative reference values of Aortic knob dimensions in Indian Population and is the first study in Indian population to compare knob width with other chest parameters.