¹⁸F-FDG PET/CT and post-treatment lung function in adolescent tuberculosis

Data on post-tuberculosis outcomes in adolescents are scarce. Although fluorine-18 fluorodeoxyglucose (¹⁸F-FDG) positron emission tomography/computed tomography (PET/CT) has been used in adult tuberculosis research, little is known about the association between PET/CT findings and functional outcomes in general.

Early FDG PET/CT images of 50 adolescents (31 female, median age 17.2 years) with confirmed pulmonary tuberculosis were read visually and quantitative data of disease burden (total lung volume, cavity volume, total hard volume and total glycolytic activity (TGA)) were extracted and tested for associations with clinical risk factors and spirometry measures after treatment completion.

Involvement of three or more lobes was present in 66% of adolescents, with consolidation in 84%, nodules in 92% and cavities in 84%. Comparatively, smokers had lower TGA values (p=0.034). Larger cavity volume was the strongest predictor of reduced forced expiratory volume in 1 s (FEV₁) and forced vital capacity (FVC) post treatment (β=-1.78- -0.87; p=0.0024-0.047). Corrected total hard volume and corrected TGA were associated with FEV₁ and FVC z-scores, although no individual predictor coefficients survived correction for multiple comparisons.

PET/CT features in this adolescent cohort matched patterns described in adults and were frequently severe. Radiological severity measures were associated with poorer spirometry after treatment. More data, including longitudinal imaging and functional outcomes, are required to better understand pathophysiology in this age group.