Reliability of chest X-ray in diagnosing active Pulmonary Tuberculosis in reference to chest CT at Radiology department of St Paul’s Hospital Millennium Medical College , AA , September 2019

Abstract

Abstract : Background - Tuberculosis (TB) is a significant public health problem in Ethiopia . Imaging plays a pivotal role in the diagnosis and management of tuberculosis. The introduction of HRCT in radiology field has improved the diagnosis of TB. But the overall utilization of CT is in its infancy in our country due to expensive cost of the machines and inadequate amount of trained radiologists. Chest X ray has been the mainstay of imaging diagnosis for TB and thereby most previous documents in our country compared CXR diagnosis with sputum microscopy and culture. Objective: To assess the reliability of CXR in the diagnosis of “active” pulmonary TB compared to chest CT in patients with clinical presumptive TB at Saint Paul’s Hospital Millennium Medical College (SPHMMC) radiology department and subsequently characterize the commonly misdiagnosed cases on chest radiographs. Methods: A retrospective hospital based review was conducted on the chest X rays of outpatients imaged at the SPHMMC radiology department in the 12 months from April 2018 – March 2019 with chest CT suggestive findings of active pulmonary TB. The data was analyzed by percentage agreement and Cohen’s statistics using SPSS version 20. Result : 40 CXRs were studied and 32 (80 %) were classified as “abnormal TB suggestive” and 8 (20 %) as “normal” or “abnormal but not TB suggestive”. The inter reader agreement calculated showed 77.5 % percentage agreement and a Cohen’s statistic value of 0.477. Conclusion – This study found a moderate agreement between the two image interpreters on the final diagnosis of active TB with a cohen’s statistic value of 0.477. The specific disease pattern with the highest degree of agreement between the readers was pleural effusion with a Cohen’ value of 0.826 and the lowest for fibrocystic changes of TB.