The value of lateral chest X-rays for the diagnosis of lymphadenopathy in children with pulmonary tuberculosis
Poyiadji, Thalia Leto
INTRODUCTION: Tuberculosis (TB) is an important public health issue, but diagnosis in children can be challenging. The radiological hallmark of pulmonary TB (PTB) in children is mediastinal lymphadenopathy, however there is inter-observer variability in detecting this. The value of the lateral CXR in addition to the frontal view to detect lymphadenopathy has not been well studied. OBJECTIVES: To investigate the prevalence of lymphadenopathy in children with confirmed PTB detected on frontal compared to frontal-lateral CXRs. METHODS: This was a secondary analysis of a study from Red Cross Children’s Hospital in Cape Town. Children with definite TB and a control group (Lower respiratory tract infection other than TB) who had frontal and lateral CXRs were included in this study. Three radiologists independently read the CXRs in 2 separate sittings (frontal CXR and ‘combination frontallateral’ CXR). A 3 reader consensus reading was used during data analysis. Odds ratios and 95% confidence intervals were calculated to determine the presence of lymphadenopathy. Kappa statistics were calculated to determine inter reader agreement. RESULTS: Of 172 children (88 confirmed TB and 84 control children), with a median age of 29 months, lymphadenopathy was reported in 86 (50%) patients on the frontal CXR alone and in 143 (83%) on the frontal-lateral CXR combination, p= 0.00. Amongst confirmed PTB cases, 52 (60%) had lymphadenopathy on the frontal CXR alone while 72 (82%) had lymphadenopathy on the frontal-lateral CXR combination, p= 0.00. Amongst the control group, 34 (40%) had lymphadenopathy on the frontal CXR alone while 71 (85%) had lymphadenopathy on the frontal-lateral CXR combination, p= 0.00. The consensus reading using a frontal-lateral CXR combination resulted in a 5 fold increase (OR 4,9; 95% CI 2,9-8,4) in diagnosis of lymphadenopathy compared to a frontal CXR only. Overall inter reader agreement for all 3 readers was fair on both the frontal CXR (Kappa= 0,21) and the frontal-lateral CXR (Kappa= 0,23) combination. CONCLUSION: The addition of a lateral view to the frontal CXR increased detection of lymphadenopathy, however, the prevalence of lymphadenopathy was similar in children with PTB and those in the control group, with fair inter reader agreement.
A research report submitted to the Faculty of Health Sciences, University of Witwatersrand, Johannesburg, in fulfilment of the requirements for the degree of Master of Medicine in the branch of Diagnostic Radiology Johannesburg 2018.