Is HRCT reliable in determining disease activity in pulmonary tuberculosis?"

Aims and Objectives: The purpose of our study is to (1) determine the activity of disease based on the HRCT findings (2) to define indications for the use of HRCT in evaluation of Pulmonary TB and (3) to determine whether additional information provided by HRCT alters clinical management of the disease. Materials and Methods: The present study was carried out at Shree Sayajirao General Hospital (SSGH), Baroda, Gujarat, India from January 2002 to December 2002. Twenty five patients with sputum positive post-primary pulmonary TB were studied prospectively with chest radiographs and HRCT. The diagnosis of active TB was based on detection of acid-fast bacilli in sputum. None of the patients in our study population was HIV positive. All patients underwent x-ray chest and HRCT chest (Philips Tomoscan, Best, Netherlands). The pattern, extent and severity of HRCT findings were recorded and compared with the plain x-ray findings. The gathered information and investigations were subjected to statistical analysis. Results: Our study population consisted of sputum positive (AFB positive) 25 patients, 22 of them were newly diagnosed/ suspected post-primary tuberculosis (GROUP 1) and 3 of them had taken six months of AKT (GROUP 2). Our study included 22 males and 3 females with average age of 38 years (range, 14-65 years.) In total chest radiographic signs of active tuberculosis were seen in twelve (48%) patients. HRCT showed evidences of active tuberculosis in all 22 patients of newly diagnosed tuberculosis; and in 2 out of 3 patients with prior history of AKT. Thus, total of 24 (96%) patients had evidence of active pulmonary TB on HRCT. One patient with prior history of AKT showed evidence of pulmonary Koch's sequel. Conclusion: Although chest radiography remains the foremost imaging technique in the evaluation of pulmonary TB, HRCT can be useful in certain circumstances and can provide important information in the diagnosis and management of the disease. HRCT is helpful in the distinction of active form inactive TB. HRCT is better than plain chest radiograph in identification of extent of pulmonary TB, especially subtle areas of consolidation, cavitation, bronchogenic and millary spread. HRCT is recommended when the radiographic findings are normal or inconclusive and tuberculosis is suspected clinically for the confirmation of diagnosis and determination of activity.