Archives of Medical Research 36 (2005) 166–170 ORIGINAL ARTICLE The Roles of HRCT and Clinical Parameters in Assessing Activity of Suspected Smear Negative Pulmonary Tuberculosis Ergun Tozkoparan, a Omer Deniz, a Faruk Ciftci, d Erkan Bozkanat, d Mesut Bicak, d Hakan Mutlu, c Fatih Ors, b Hayati Bilgic a and Necmettin Demirci a a Department of Pulmonary Medicine, b Department of Radiology, Gulhane Military Medical Academy, Ankara, Turkey c Department of Radiology, Haydarpasa Training Hospital, Gulhane Military Academy, Ankara, Turkey d Camlica Chest Disease Hospital, Gulhane Military Medical Academy, Istanbul, Turkey Received for publication July 27, 2004; accepted November 17, 2004 (ARCMED-D-04-00046). Background. Smear-negative pulmonary tuberculosis (SNPTB) constitutes a major problem in countries with a moderate or high TB prevalence. The value of high-resolution computed tomography (HRCT), chest x-ray and other clinical findings in determining activity of SNPTB were investigated. Methods. The study population consisted of 85 patients with suspected SNPTB, of whom 52 were confirmed as active pulmonary TB according to either culture positivity for Mycobacteriun tuberculosis or demonstration of caseous granulomatous inflammation. The remaining 33 patients accepted inactive TB sequel. Results. Cough and expectoration were significantly frequent in inactive group whereas chest pain was detected higher in active patients. Sensitivity, specificity, positive predictive value, negative predictive value and diagnostic accuracy of HRCT in detecting disease activity were 88, 88, 92, 83 and 88%, respectively. Centrilobular nodules, other non- calcified nodules, consolidation and cavity were significantly higher on HRCT in active group. Chest x-ray scores that were graded 1 to 3 showed a linear trend for the disease activity. Conclusions. HRCT has good diagnostic value in detecting activity of SNPTB, and some clinical findings may help in predicting the activity.  2005 IMSS. Published by Elsevier Inc. Key Words: HRCT, Clinical findings, Chest x-ray, Smear-negative pulmonary tuberculosis. Introduction Tuberculosis (TB) remains significant in many undeveloped or developing countries and industrialized ones as well. Early identification and treatment of active cases, especially those with positive sputum smear for acid-fast bacilli (AFB), are essential for TB control. However, patients with active TB whose sputum smears are negative may contribute to disease (1). In addition, as already known, sensitivity of AFB smear is low and prevalence of smear-negative active pulmonary TB (PTB) has been increasing among patients co-infected simultaneously by human immunodeficiency Address reprint requests to: Dr. Ergun Tozkoparan, Assistant Professor, Department of Pulmonary Medicine, Gulhane Military Medical Academy, GATA Gogus Hastaliklari, B Binasi Etlik, 06018 Ankara, Turkey. Phone: (+90) (312) 3044412; E-mail: etozkoparan@gata.edu.tr 0188-4409/05 $–see front matter. Copyright  2005 IMSS. Published by Elsevier Inc. doi: 10.1016/j.arcmed.2004.12.010 virus (2,3). In this regard, new efforts have been made to assess activity of the disease in two ways: one is to develop rapid diagnostic methods, the other is to make presumptive diagnosis of PTB more accurately, based on clinical and radiographic findings. Most studies investigating the validity of clinical and radiographic findings to predict PTB were designed to assess an accurate isolation policy in a given patient with normal or abnormal chest x-ray and respiratory symptoms (4–9). Although a realistic isolation strategy is an important issue, the problem is somewhat different in countries with a high or medium prevalence of TB. In these countries, there are a significant number of patients with healed lesions attributable to TB on chest x-ray, and some of these inactive lesions may reactivate, resulting in post-primary PTB while others may not. A decision to treat or not to treat a smear- negative patient with radiographic findings compatible with