[⁶⁸Ga]Ga-FAPI-46 PET/CT imaging in neuromelioidosis: a case series demonstrating potential utility in diagnosis and response assessment.

Abstract

Neuromelioidosis is a rare but severe manifestation of melioidosis with central nervous system (CNS) involvement, caused by gram negative saprophytic bacteria named Burkholderia pseudo-mallei and is associated with high morbidity and mortality. Early and accurate detection of active disease is crucial for appropriate management. We report a series of three cases of neuromelioidosis evaluated using Gallium-68–labelled fibroblast activation protein inhibitor ([⁶⁸Ga]Ga-FAPI) positron emission tomography/computed tomography (PET/CT). [⁶⁸Ga]Ga-FAPI, a novel molecular imaging tracer targeting activated fibroblasts, has demonstrated utility in imaging infection and inflammation in addition to malignancies. Unlike [¹⁸F]FDG (F-18 Fluorodeoxyglucose), [⁶⁸Ga]Ga-FAPI shows negligible physiological uptake in normal brain parenchyma, allowing superior lesion conspicuity. In the three cases reported, [⁶⁸Ga]Ga-FAPI PET/CT clearly demonstrated active CNS inflammatory lesions better than [¹⁸F]FDG PET-CT, facilitating accurate disease assessment and aiding clinical decision-making. The findings on [⁶⁸Ga]Ga-FAPI PET/CT correlated with the MRI findings and further it was found to be better than MRI for response evaluation in one case. This highlights the potential role of [⁶⁸Ga]Ga-FAPI PET/CT as a promising functional imaging modality in the evaluation of neuromelioidosis and other CNS infections.