Comparison of 68Ga-DOTATOC and 18F-FDG Thoracic Lymph Node and Pulmonary Lesion Uptake Using PET/CT in Postprimary Tuberculosis.

Tuberculosis (TB) remains one of the world's leading infectious cause of morbidity and mortality. Positron emission tomography (PET) associated with computed tomography (CT) allows a structural and metabolic evaluation of TB lesions, being an excellent noninvasive alternative for understanding its pathogenesis. DOTATOC labeled with gallium-68 (68Ga-DOTATOC) can bind to somatostatin receptors present in activated macrophages and lymphocytes, cells with a fundamental role in TB pathogenesis. We describe 68Ga-DOTATOC uptake distribution and patterns in thoracic lymph nodes (LN) and pulmonary lesions (PL) in immunocompetent patients with active postprimary TB, analyze the relative LN/PL uptake, and compare this two tracer's uptake. High uptake of both radiotracers in PL and LN was demonstrated, with higher LN/PL ratio on 68Ga-DOTATOC (P < 0.05). Considering that LN in immunocompetent patients are poorly studied, 68Ga-DOTATOC can contribute to the understanding of the complex immunopathogenesis of TB.