Correlation Between Aortic Knob Diameter and Cardiothoracic Ratio on Plain Chest Radiograph in Indian Population

Abstract

Purpose: The identification of the aortic knob in a chest radiograph holds significance, as it can serve as an initial indicator of cardiovascular disease. The cardiothoracic ratio, a cost-effective and straightforward tool, plays a crucial role in estimating heart size. This study aims to assess the relationship between aortic knob diameter and cardiothoracic ratio based on age and gender.

Method: This was an observational prospective study of 315 individuals between the ages of 10-70 years were assessed, had no thoracic deformity with no past or present cardiovascular disease were included.

Result: The mean value of aortic knob diameter for males & females was 2.7 & 2.5cm it increases with age and males have higher value. The mean cardiothoracic ratio was 0.46 for females and 0.44 for males, it increased with age until the fifth decade and was higher in females.

Conclusion: The present study shows the demonstrate a significant positive correlation between aortic knob diameter and cardiothoracic ratio. The mean aortic knob diameter increased with age and males had higher values than females. The mean CTR increased gradually with age and females had greater values than males. Aortic knob diameter was positively correlated with transverse heart diameter (THD), transverse thoracic diameter (TTD), and cardiothoracic ratio (CTR).