Sébastien Bommart1, Jeremy Charriot2, Nicolas Nagot3, Hélène Vernhet-Kovacsik4, Marie P Revel5, Clément Boissin6, Arnaud Bourdin2, Edouard Tuaillon7. 1. Department of Radiology, CHU Montpellier, avenue Doyen Gaston Giraud, 34000 Montpellier, France; PhyMedExp Inserm U1046, UMR9214 CNRS, 34000 Montpellier, France. Electronic address: s-bommart@chu-montpellier.fr. 2. PhyMedExp Inserm U1046, UMR9214 CNRS, 34000 Montpellier, France; Department of Respiratory Diseases, CHU Montpellier, 34000 Montpellier, France. 3. Department of Biostatistics, CHU Montpellier, 34000 Montpellier, France. 4. Department of Radiology, CHU Montpellier, avenue Doyen Gaston Giraud, 34000 Montpellier, France. 5. Department of Radiology, Cochin Hospital, Assistance Publique-Hopitaux de Paris, 75014 Paris, France; Université de Paris, Faculté de Médecine, 75006 Paris, France. 6. Department of Respiratory Diseases, CHU Montpellier, 34000 Montpellier, France. 7. UMR1058 Inserm, 34000 Montpellier, France; Department of Bacteriology-Virology, CHU Montpellier, 34000 Montpellier, France.
Abstract
PURPOSE: The purpose of this study was to evaluate the capabilities of chest computed tomography (CT) in distinguishing between active and latent tuberculosis in patients positive for interferon-gamma release assay (IGRA) testing, and to compare the performance of CT with that of quantitative IGRA testing in a low incidence setting. MATERIALS AND METHODS: Patients with latent or active tuberculosis define by an IGRA positive test were retrospectively recruited. Sensitivity, specificity and accuracy were determined for CT variables and quantitative IGRA results. Final diagnosis of active tuberculosis was based on clinical data and microbiological culture. Univariable and multivariable analyses were performed using logistic regression model to identify CT variables associated with the diagnosis of active tuberculosis. RESULTS: A total of 92 patients with positive IGRA results who underwent CT examination were included. There were 54 men and 38 women with a mean age of 53.5±18 (SD) years (range: 40-68 years). Of them, 22 patients (24%) had positive Mycobacterium tuberculosis culture and 70 (76%) had latent tuberculosis. Among CT variables, consolidation had the greatest sensitivity (77%; 95%CI: 60-95%) and "tree-in-bud" the greatest specificity (97%; 95% CI: 93-100%) for the diagnosis of active tuberculosis. At univariable analysis "tree-in-bud", splenic calcification and non-calcified lung nodules were the significant variables independently associated with active tuberculosis. At multivariable analysis, the adjusted odds ratio of "tree-in-bud" was 42.91 (95% CI: 5.62-327.42). Using an optimal threshold of 51 spots, quantitative IGRA yielded 64% sensitivity (95% CI: 44-84%) and 61% specificity (95% CI: 50-73%) for the diagnosis of active tuberculosis. CONCLUSIONS: In a low incidence setting, chest CT, especially when "tree-in-bud" pattern is present, is superior to quantitative IGRA testing to identify patients with active tuberculosis among those with positive IGRA testing.
PURPOSE: The purpose of this study was to evaluate the capabilities of chest computed tomography (CT) in distinguishing between active and latent tuberculosis in patients positive for interferon-gamma release assay (IGRA) testing, and to compare the performance of CT with that of quantitative IGRA testing in a low incidence setting. MATERIALS AND METHODS:Patients with latent or active tuberculosis define by an IGRA positive test were retrospectively recruited. Sensitivity, specificity and accuracy were determined for CT variables and quantitative IGRA results. Final diagnosis of active tuberculosis was based on clinical data and microbiological culture. Univariable and multivariable analyses were performed using logistic regression model to identify CT variables associated with the diagnosis of active tuberculosis. RESULTS: A total of 92 patients with positive IGRA results who underwent CT examination were included. There were 54 men and 38 women with a mean age of 53.5±18 (SD) years (range: 40-68 years). Of them, 22 patients (24%) had positive Mycobacterium tuberculosis culture and 70 (76%) had latent tuberculosis. Among CT variables, consolidation had the greatest sensitivity (77%; 95%CI: 60-95%) and "tree-in-bud" the greatest specificity (97%; 95% CI: 93-100%) for the diagnosis of active tuberculosis. At univariable analysis "tree-in-bud", splenic calcification and non-calcified lung nodules were the significant variables independently associated with active tuberculosis. At multivariable analysis, the adjusted odds ratio of "tree-in-bud" was 42.91 (95% CI: 5.62-327.42). Using an optimal threshold of 51 spots, quantitative IGRA yielded 64% sensitivity (95% CI: 44-84%) and 61% specificity (95% CI: 50-73%) for the diagnosis of active tuberculosis. CONCLUSIONS: In a low incidence setting, chest CT, especially when "tree-in-bud" pattern is present, is superior to quantitative IGRA testing to identify patients with active tuberculosis among those with positive IGRA testing.