Assessment of the Cardiothoracic Ratio and Its Association with Gender and Age: A Nigerian Study

Abstract

Cardiothoracic ratio (CTR) evaluation is a useful screening method used to detect cardiomegaly. It varies in different populations due to genetic, geographical and environmental factors that influence body morphology. This study aimed at assessing the CTR and determining its association with gender and age among adult Nigerians. This retrospective cross-sectional study was conducted in the Radiology Department of a Teaching Hospital in Delta State after obtaining ethical clearance. Postero-anterior chest radiographs of 200 adults (108 males and 92 females) were used to measure the transverse cardiac diameter (TCD) and transverse thoracic diameter (TTD) in centimeters (cm). These were used to compute the CTR (TCD/TTD*100). Statistical Package for Social Sciences version 22.0 was used to analyze the data. Independent t-test and analysis of variance (ANOVA) were used to determine the differences in the measurements with regards to gender and age-groups respectively. The correlation that exists between the variables and their association with age were assessed using Pearson’s correlation. P value was set at < 0.05. The TTD and TCD were significantly larger in males than in females (p=0.001 each) while the CTR was significantly larger in females than in males (p=0.016). The TTD and CTR showed significant differences in the various age groups (p=0.002, 0.031) (p=0.195). The two diameters showed a significant positive correlation with age (0<r<0.5). The study provides the normal mean CTR values for the studied population based on age and gender which will help clinicians in the screening for heart conditions. This will enhance early diagnosis and intervention. Keywords: cardiomegaly, thoracic diameter, cardiac diameter, chest radiographs, diagnosis, cardiothoracic ratio