Pulmonary tuberculosis is a serious public health issue. Previous studies have shown that patients with cavities on initial chest X rays (CXR) before tuberculosis treatment may need prolonged treatment. High resolution chest tomography (HRCT) can yield more details concerning pulmonary parenchyma. In this study, we compared the cavity-detection efficacies for CXR and HRCT in 25 patients. Two revealed cavities on HRCT but not on CXR. The reverse was noted in another patient. These patients would have received inappropriate treatment duration if CXR had been performed solely. HRCT would seem to decrease the rate of relapse and resistance in the beginning of treatment for pulmonary tuberculosis.