Comparison of Ga-68-DOTATOC and F-18-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 (Ga-68-DOTATOC) can bind to somatostatin receptors present in activated macrophages and lymphocytes, cells with a fundamental role in TB pathogenesis. We describe Ga-68-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 Ga-68-DOTATOC (P < 0.05). Considering that LN in immunocompetent patients are poorly studied, Ga-68-DOTATOC can contribute to the understanding of the complex immunopathogenesis of TB.