RESUMO
INTRODUCTION: Dementia with Lewy bodies (DLB) is the second most common neurodegenerative dementia of the elderly. Its early diagnosis is a clinical challenge due to overlapping symptoms of various neurodegenerative diseases. Early diagnosis is essential for patient management avoiding neuroleptic medications that harbor the risk of causing further deterioration. Functional imaging allows accurate diagnosis and improves the degree of confidence in the diagnosis. Its advantage is based on the ability to identify biochemical changes that precede structural changes, thereby providing valuable information at early stages of the disease. Another advantage is its ability to provide a non-invasive neurobiological evaluation as well as an objective follow-up algorithm. We present a patient with cognitive and motor decline, in which anatomical imaging (MRI) failed to recognize a specific morphological abnormality. Combined data of two PET-CT brain scans using two different radiotracers raised the diagnosis of DLB. Cortical metabolism was obtained by PET with labeled glucose (FDG) and the dopaminergic activity by labeled precursor (F-DOPA) of the neurotransmitter Dopamine. In times to come, with the development of novel specific tracers, diagnostic confidence is expected to improve, along with development of new approaches of therapy.