Imaging in extrapulmonary tuberculosis

Tuberculosis (TB) remains a major global public health problem, with 1.5 million deaths annually worldwide. One in five cases of TB present as extrapulmonary TB (EPTB), posing major diagnostic and management challenges. Mycobacterium tuberculosis adapts to a quiescent physiological state and is notable for its complex interaction with the host, producing poorly understood disease states ranging from latent infection to active clinical disease. New tools in the diagnostic armamentarium are urgently required for the rapid diagnosis of TB and monitoring of TB treatments, and to gain new insights into pathogenesis. The typical and atypical imaging features of EPTB are reviewed herein, and the roles of several imaging modalities for the diagnosis and management of EPTB are discussed

PET/CT features of extrapulmonary tuberculosis at first clinical presentation: a cross-sectional observational ¹⁸F-FDG imaging study across six countries

BACKGROUND: A large proportion of the huge global burden of Extrapulmonary tuberculosis (EPTB) are treated empirically without accurate definition of disease sites, and extent of multi-organ disease involvement. Positron emission tomography (PET) imaging using 18F-FDG in TB could be a useful imaging technique for localising disease sites and extent of disease. METHODS: We conducted a study of HIV-negative adult patients with a new clinical diagnosis of EPTB across 8 centres located in 6 countries: India, Pakistan, Thailand, South Africa, Serbia, and Bangladesh to assess the extent of disease and common sites involved at first presentation. 18F-FDG PET/CT scans were performed within 2 weeks of presentation. FINDINGS: A total of 358 patients with EPTB (189 females; 169 males) were recruited over 45 months. Age range 18-83 years (females: median 30 years; males: median 38 years). 350/358 (98%) patients (183 female, 167 male) had positive scan. 118/350 (33.7%) had a single extrapulmonary site and 232/350 (66.3%) had more than one site (organ) affected. Lymph nodes, skeletal, pleura and brain were common sites. 100/358 (28%) of EPTB patients had 18F-FDG PET/CT positive sites in the lung. 110 patients were 18F-FDG PET/CT positive in more body sites than were noted clinically at first presentation and 160 patients had the same number of positive body sites. INTERPRETATION: 18F-FDG PET/CT scan has potential for further elucidating the spectrum of disease, pathogenesis of EPTB, and monitoring the effects of treatment on active lesions over time, and requires longitudinal cohort studies, twinned with biopsy and molecular studies