Outbreak of pulmonary tuberculosis in lodging high school, should X-ray be replaced by CT?

Abstract Objective On April 9th 2016, active pulmonary TB was identified in a 17-year-old student when performing CT and sputum culture. On April 10th, two students who had close contact with him on performing CT scan revealed active pulmonary tuberculosis (TB) lesions. Methods Tuberculin skin test (TST) was performed on 1009 students. Chest X-ray (CXR) examination and CT was performed on 73 students who had close contacts with the first case or with a strong positive result of TST without close contact. The diagnostic value of CXR and CT in early stage of pulmonary TB infection was analyzed by paired chi square or Fisher exact test. Results Of the 1009 students, 239 (23.7%) were TST positive. Of the 73 students who underwent CXR and CT, the sensitivity and the specificity of diagnosing suspected/active TB were (24.5%, 91.7% respectively), and (98.0%, 83.3% respectively). A statistically significant difference in diagnosing suspected/active TB with CXR and CT was observed (χ2 = 55.705, P＜0.001). Conclusions The students with outbreak of pulmonary TB seldom had positive sputum culture and symptoms. Chest CT has higher sensitivity than X-ray plain film.