Measurement of Main Pulmonary Artery Diameter and its Ratio with Ascending Aorta in Indian Population by Multi Detector Computed Tomography

Abstract

Introduction: An increase in Pulmonary Artery (PA) pressure is associated with an increase in its diameter. Hence, it is necessary to know the normal range of Main Pulmonary Artery Diameter (MPAD). An attempt has been made to know the same among the Indian population. Aim: To determine the normal range of reference values for diameter of Main Pulmonary Artery (MPA) and its relation with Ascending Aorta (AA) in Indian population. Materials and Methods: A prospective cross-sectional study was conducted between October 2018 and September 2019 ((380 males, 120 females) between the age of 30-65 years). Data from the contrast CT scans of thorax of 500 subjects such as those patients with cough under evaluation, suspected lung nodule, chest wall lesions, primary or secondaries in the lung, etc., who visited the Department of Radio-diagnosis, in the Medical College of South India were analysed. Further, healthy population was also defined as those who were free from chronic cardiopulmonary illness in particular with regard to present study, which would affect the diameter of great vessels including that of PA and aorta. MPA and ascending aortic diameters were measured at the level of pulmonary artery bifurcation, viewed at fixed mediastinal window settings. Statistical Package for Social Sciences (SPSS) version 20, inferential statistics like Unpaired-t test were used to test the significant difference for variables between the two groups (males and females). The level of significance was set at 5%. Results: The MPADs of whole population ranged between 15.6-31.6 mm, with mean diameter of 23.08±2.81 mm. Correlation between age and MPAD was statistically significant (p-value <0.001), while sex-specific MPAD was not significant. The mean AA diameter was 27.15±2.6 mm. The mean AA diameter in males was 27.76±3.2 mm, and 26.67±2.0 mm in females with statistical significance (p-value 0.001) between the groups. The diameter ratio of MPA to AA was 0.85. Conclusion: In present study, the normal ranges of diameter of PA and its ratio with AA were defined among Indians. The diameter ratio of MPA to AA appears to be more important, as it tends to normalise the effects of anthropomorphic factors.