The Role of High Resolution Computed Tomography in the Diagnosis of Suspected Sputum Smear Negative Active Pulmonary TB

Abstract

Objective: To evaluate the diagnostic accuracy of high resolution CT (HrCT) for confirmatory evaluation of patients having active pulmonary TB (PTB) taking Acid-fast bacillus (AFB) culture reporting as standard parameter. Methods: In this cross-sectional (validation) analysis we included 200 patients having chest X-rays and clinical evidence of active TB and sputum smear (SS) –ve results. These patients were recruited from March-2019 to December-2019. Data of patients regarding baseline hematology investigations, sputum smear findings, and presenting symptoms was obtained. Sputum samples were obtained again for each patients, and sent for AFB culture reporting. The HrCT was performed in the radiology unit using a 64 slices CT machine. Results: The mean age of included patients was 53.61 ± 11.96 years. There 81 (40.5%) female and 119 (59.5%) male patients. The proportion of true positive (TP) cases was 79 (39.5%), true negative cases was 96 (48.0%), false positive (FP) cases 11 (5.5%) and false negative (FN) was 14 (7.0%). The HrCT was found to have sensitivity of 84.9%, specificity 89.7%, PPV 87.8% and NPV 87.3%. Conclusion: HrCT is a reliable imaging method for accurately diagnosis the active Pul. TB with a good sensitivity and specificity. In our view, HrCT can be used as a firstline imaging evaluation test for diagnosing pul. TB in suspected patients. Keywords: Pulmonary TB, Microbial culture, high resolution CT.Objective: To evaluate the diagnostic accuracy of high resolution CT (HrCT) for confirmatory evaluation of patients having active pulmonary TB (PTB) taking Acid-fast bacillus (AFB) culture reporting as standard parameter. Methods: In this cross-sectional (validation) analysis we included 200 patients having chest X-rays and clinical evidence of active TB and sputum smear (SS) –ve results. These patients were recruited from March-2019 to December-2019. Data of patients regarding baseline hematology investigations, sputum smear findings, and presenting symptoms was obtained. Sputum samples were obtained again for each patients, and sent for AFB culture reporting. The HrCT was performed in the radiology unit using a 64 slices CT machine. Results: The mean age of included patients was 53.61 ± 11.96 years. There 81 (40.5%) female and 119 (59.5%) male patients. The proportion of true positive (TP) cases was 79 (39.5%), true negative cases was 96 (48.0%), false positive (FP) cases 11 (5.5%) and false negative (FN) was 14 (7.0%). The HrCT was found to have sensitivity of 84.9%, specificity 89.7%, PPV 87.8% and NPV 87.3%. Conclusion: HrCT is a reliable imaging method for accurately diagnosis the active Pul. TB with a good sensitivity and specificity. In our view, HrCT can be used as a firstline imaging evaluation test for diagnosing pul. TB in suspected patients. Keywords: Pulmonary TB, Microbial culture, high resolution CT.