Utilization of Positron Emission Tomography with FDG-F¹⁸ in the differential diagnosis of cerebral neurodegenerative diseases in individuals of the state of Ceará, Brazil

Positron Emission Tomography (PET) is a technique capable of quantifying biological processes based on the distribution of radiotracer injected into patients. The most commonly used marker in cognitive disorders for evaluation of cerebral glycolytic metabolism is Fluorodeoxyglucose-F¹⁸, capable of indicating neuronal activity, oxygen consumption, synaptic changes and molecular changes. The objective of this work was to investigate the role of PET in the evaluation of dementia through the use of radiopharmaceutical as a biomarker of cerebral glycolytic metabolism. We used a database from a radiology clinic in Fortaleza, where PET exams were selected from July 2013 to December 2017. Through the present study, we evaluated socio-demographic information, possible brain morphological changes and the pattern of distribution of the radiopharmaceutical in the cerebral parenchyma of 21 patients referred to the nuclear medicine service of a private clinic in Fortaleza. We selected only those patients who presented some clinical picture of cognitive deficit.Data analysis was performed through inspection of patient records, reports and images of the exams filed in the service database. Patients were divided into two groups: Without Dementia Group, patients with negative results for neurodegenerative disease, and Dementia Group, composed of patients with positive results, who presented with cerebral alterations or patterns of radiopharmaceutical hypocaptation in certain regions of the brain. Morphometric measurements were performed using Extended Brilliance TM Workspace software. It was verified that the mean age of the patients in the Without Dementia Group was 59.6 years and the Dementia Group was 69.4 years. It was observed that 61.9% of the patients presented positive results for morphological alterations and cerebral glycolytic metabolism. Regarding the sex, 87.5% of the male and female patients had a positive diagnosis, while only 46.15% of the female patients had positive results. Regarding the morphofunctional brain alterations, 76.92% of the Dementia Group patients presented temporal hypometabolism, 38.46% frontal hypometabolism, 15.38% hypometabolism in the region of the cingulate gyrus and 30.77% hypometabolism in the parietal region. Temporal atrophy was observed in 23.07% of the cases and cerebral volume reduction in 15.38% of the positive patients. In the Without Dementia Group, no anatomical alterations and glycolytic metabolism were observed. We conclude that 76.92% of the positive patients presented alterations compatible with Alzheimer's disease. It was verified that Positron Emission Tomography demonstrates a good efficacy in the differential diagnosis of Alzheimer's Disease, enabling adequate treatment and consequently improving the patients' quality of life. (author)