A few 18 F-FDG (FDG) PET-CT studies revealed the presence of brain hypermetabolism in the brainstem and cervical spinal cord of patients within the Amyotrophic Lateral Sclerosis continuum (ALS/FTD). We aim to investigate this finding through a hybrid PET-MR system, allowing a more precise spatial pattern of metabolic changes in the brainstem and cervical spinal cord. Method:Twenty-eight patients with a diagnosis of ALS or behavioural variant FTD plus motoneuron disease and thirteen control subjects underwent 18 F-FDG PET-MR study.Mean normalized FDG uptake values in the midbrain/pons, medulla oblongata, and cervical spinal cord defined on individual's MR scans were compared between groups.Furthermore, the associations between regional FDG uptake values and clinical and demographic characteristics, including gene mutation, type of onset (bulbar, spinal, dementia), and clinical characteristics were investigated. Results:A significant (p < 0.005) increment in glucose metabolism in the midbrain/pons and medulla oblongata was found in ALS/FTD patients (spinal-ALS and FTD-MND subgroups) in comparison to controls. No relevant associations between clinical and metabolic features were reported, although medulla oblongata hypermetabolism was associated with shortened survival (p < 0.001). Conclusion:Increased glucose metabolism in the brainstem might be due to neuroinflammation, one of the key steps in the pathogenic cascade that leads to neurodegeneration in ALS/FTD. FDG PET-MR could be a valuable tool to assess glial changes in the ALS/FTD spectrum and could serve as a prognostic biomarker. Large prospective initiatives would likely shed more light on the promising application of PET-MR in this setting.

Objective: The use of regorafenib in recurrent glioblastoma patients has been recently approved by the Italian Medicines Agency (AIFA) and added to the National Comprehensive Cancer Network (NCCN) 2020 guidelines as a preferred regimen. Given its complex effects at the molecular level, the most appropriate imaging tools to assess early response to treatment is still a matter of debate. Diffusion-weighted imaging and O-(2-18F-fluoroethyl)-L-tyrosine positron emission tomography ([18F]FET PET) are promising methodologies providing additional information to the currently used RANO criteria. The aim of this study was to evaluate the variations in diffusion-weighted imaging/apparent diffusion coefficient (ADC) and [18F]FET PET-derived parameters in patients who underwent PET/MR at both baseline and after starting regorafenib. Methods: We retrospectively reviewed 16 consecutive GBM patients who underwent [18F]FET PET/MR before and after two cycles of regorafenib. Patients were sorted into stable (SD) or progressive disease (PD) categories in accordance with RANO criteria. We were also able to analyze four SD patients who underwent a third PET/MR after another four cycles of regorafenib. [18F]FET uptake greater than 1.6 times the mean background activity was used to define an area to be superimposed on an ADC map at baseline and after treatment. Several metrics were then derived and compared. Log-rank test was applied for overall survival analysis. Results: Percentage difference in FET volumes correlates with the corresponding percentage difference in ADC (R = 0.54). Patients with a twofold increase in FET after regorafenib showed a significantly higher increase in ADC pathological volume than the remaining subjects (p = 0.0023). Kaplan–Meier analysis, performed to compare the performance in overall survival prediction, revealed that the percentage variations of FET- and ADC-derived metrics performed at least as well as RANO criteria (p = 0.02, p = 0.024 and p = 0.04 respectively) and in some cases even better. TBR Max and TBR mean are not able to accurately predict overall survival. Conclusion In recurrent glioblastoma patients treated with regorafenib, [18F]FET and ADC metrics, are able to predict overall survival and being obtained from completely different measures as compared to RANO, could serve as semi-quantitative independent biomarkers of response to treatment. Advances in knowledge Simultaneous evaluation of [18F]FET and ADC metrics using PET/MR allows an early and reliable identification of response to treatment and predict overall survival.

Recently, vaccination against COVID-19 has gained wide diffusion, especially among vulnerable individuals, such as cancer patients. At the same time, patients have been undergoing PET/CT examinations after vaccination in an increasing number, and cases of false-positive axillary nodal uptake have been described, mostly at 18 F-FDG PET. Here, we describe the case of both 68 Ga-DOTATOC and 18 F-FDG axillary nodal uptake in a young woman affected by a metastatic retroperitoneal paraganglioma.

Introduction: The use of regorafenib in recurrent glioblastoma patients has been recently approved by the Italian Medicines Agency (AIFA) and added to the National Comprehensive Cancer Network (NCCN) 2020 guidelines as a preferred regimen. Given its complex effects at the molecular level, the most appropriate imaging tools to assess early response to treatment is still a matter of debate. DWI and 18F–FET PET are promising methodologies providing additional information to the currently used RANO criteria. The aim of this study was to evaluate the variations in DWI/ADC- and 18F-FET PET-derived parameters in patients who underwent PET/MR at both baseline and soon after starting regorafenib. Method: We retrospectively selected 16 consecutive GBM patients who underwent 18F–FET PET/MR before and after two cycles of regorafenib. Patients were sorted into stable (SD) or progressive disease (PD) categories in accordance with RANO criteria. We were also able to analyze 4 SD patients who underwent a third PET/MR after another 4 cycles of regorafenib. 18F–FET uptake greater than 1.6 times the mean background activity was used to define an area to be superimposed on an ADC map at baseline and soon after treatment. A number of metrics were then derived and compared. Result: The average increases in FET and ADC pathological volumes were higher in PD than in SD patients, although in neither case did the difference reach significance. However, when the percentage difference in FET volumes was plotted against the corresponding percentage difference in ADC, a correlation was observed (R = 0.54). Patients with a twofold increase in FET after regorafenib showed a significantly higher increase in ADC pathological volume than the remaining subjects (p = 0.0023). Conclusion: In recurrent glioblastoma patients treated with regorafenib, 18F-FET and ADC metrics, being obtained from completely different measures, could serve as semi-quantitative independent biomarkers of response to treatment. These promising parameters should be tested in a larger cohort of glioblastoma patients treated with regorafenib.