Relationship between CT Findings of Pulmonary Tuberculosis and Acid-Fast Bacilli Sputum Smears

Background and purpose: Computed tomography (CT) scan is of great help in confirming the diagnosis of tuberculosis (TB) before the sputum test result. The purpose of this study was to investigate the relationship between pulmonary involvement patterns in CT scans of TB patients with positive sputum smears. Materials and methods: This retrospective descriptive-analytical study was conducted using the records of TB patients admitted to Ghaemshahr Razi Hospital between 2012 and 2018. Demographic information and CT scan reports were collected and compared with the sputum smear results. Results: The records of 271 patients (185 men and 86 women) with an average age of 49.31±15.08 years were examined. Sputum smears were positive in 191 (70.5 %) patients and negative in 80 (29.5 %). The most prevalent lesions were cavitation (72.7%) and consolidation (42.8%), and the most common locations were the upper lobe of the right lung (61.3%) and the upper lobe of the left lung (53.5%). Cavitary and consolidation lesions were significantly more common in patients with smear positive TB (P<0.001). Cavity observation significantly increased as the positive smear level rose (P<0.001). Conclusion: Cavitary and consolidation lesions were more prevalent in patients with positive smears, whereas less common lesions were seen more in those with negative smears. Therefore, the pattern of lung lesions shown on the CT scan is linked to the sputum smear result.