Prevalence of interstitial pneumonia suggestive of COVID-19 at 18F-FDG PET/CT in oncological asymptomatic patients in a high prevalence country during pandemic period: a national multi-centric retrospective study.

PURPOSE: To assess the presence and pattern of incidental interstitial lung alterations suspicious of COVID-19 on fluorine-18-fluorodeoxyglucose positron emission tomography (PET)/computed tomography (CT) ([18F]FDG PET/CT) in asymptomatic oncological patients during the period of active COVID-19 in a country with high prevalence of the virus. METHODS: This is a multi-center retrospective observational study involving 59 Italian centers. We retrospectively reviewed the prevalence of interstitial pneumonia detected during the COVID period (between March 16 and 27, 2020) and compared to a pre-COVID period (January-February 2020) and a control time (in 2019). The diagnosis of interstitial pneumonia was done considering lung alterations of CT of PET. RESULTS: Overall, [18F]FDG PET/CT was performed on 4008 patients in the COVID period, 19,267 in the pre-COVID period, and 5513 in the control period. The rate of interstitial pneumonia suspicious for COVID-19 was significantly higher during the COVID period (7.1%) compared with that found in the pre-COVID (5.35%) and control periods (5.15%) (p < 0.001). Instead, no significant difference among pre-COVID and control periods was present. The prevalence of interstitial pneumonia detected at PET/CT was directly associated with geographic virus diffusion, with the higher rate in Northern Italy. Among 284 interstitial pneumonia detected during COVID period, 169 (59%) were FDG-avid (average SUVmax of 4.1). CONCLUSIONS: A significant increase of interstitial pneumonia incidentally detected with [18F]FDG PET/CT has been demonstrated during the COVID-19 pandemic. A majority of interstitial pneumonia were FDG-avid. Our results underlined the importance of paying attention to incidental CT findings of pneumonia detected at PET/CT, and these reports might help to recognize early COVID-19 cases guiding the subsequent management.

Plasma antioxidants and brain glucose metabolism in elderly subjects with cognitive complaints.

PURPOSE: The role of oxidative stress is increasingly recognized in cognitive disorders of the elderly, notably Alzheimer's disease (AD). In these subjects brain(18)F-FDG PET is regarded as a reliable biomarker of neurodegeneration. We hypothesized that oxidative stress could play a role in impairing brain glucose utilization in elderly subjects with increasing severity of cognitive disturbance. METHODS: The study group comprised 85 subjects with cognitive disturbance of increasing degrees of severity including 23 subjects with subjective cognitive impairment (SCI), 28 patients with mild cognitive impairment and 34 patients with mild AD. In all subjects brain FDG PET was performed and plasma activities of extracellular superoxide dismutase (eSOD), catalase and glutathione peroxidase were measured. Voxel-based analysis (SPM8) was used to compare FDG PET between groups and to evaluate correlations between plasma antioxidants and glucose metabolism in the whole group of subjects, correcting for age and Mini-Mental State Examination score. RESULTS: Brain glucose metabolism progressively decreased in the bilateral posterior temporoparietal and cingulate cortices across the three groups, from SCI to mild AD. eSOD activity was positively correlated with glucose metabolism in a large area of the left temporal lobe including the superior, middle and inferior temporal gyri and the fusiform gyrus. CONCLUSION: These results suggest a role of oxidative stress in the impairment of glucose utilization in the left temporal lobe structures in elderly patients with cognitive abnormalities, including AD and conditions predisposing to AD. Further studies exploring the oxidative stress-energy metabolism axis are considered worthwhile in larger groups of these patients in order to identify pivotal pathophysiological mechanisms and innovative therapeutic opportunities.

Targeted therapies for advanced thyroid cancer.

PURPOSE OF REVIEW: Thyroid cancer incidence has significantly increased and the majority of cases are represented by differentiated thyroid carcinomas that are characterized by a very good prognosis. Nevertheless, after initial treatment up to 15% of patients present disease persistence or relapse and those with locally advanced or metastasized cancers that do not respond to established therapies ultimately risk death. This scenario has started to change following the development of molecular targeted therapies. This review will focus on the principles behind the use of these novel therapies and on the results of the most recent clinical trials with tyrosine kinase inhibitors (TKIs) and other targeted therapies in thyroid cancer. RECENT FINDINGS: An understanding of the molecular events involved in cancer formation has prompted the development of numerous drugs that target key molecules implicated in angiogenesis and in the maintenance of the malignant phenotype of cancer cells. The results of several phase I and phase II studies and one phase III trial testing the efficacy of these drugs in advanced thyroid cancer are now available. SUMMARY: Among the tested drugs, the TKIs sorafenib for differentiated thyroid carcinoma and vandetanib and XL184 for medullary thyroid carcinoma appear very effective and have reached phase III clinical trials. Second-generation TKIs and selective kinase inhibitors are showing even more promising profiles. Improved knowledge of the targets of the different drugs, combined with molecular profiling of the tumors to treat, will allow a tailored pharmacogenomic approach.

Evaluating 2-[18F]FDG-PET in differential diagnosis of dementia using a data-driven decision model.

2-[18F]fluoro-2-deoxy-d-glucose positron emission tomography (2-[18F]FDG-PET) has an emerging supportive role in dementia diagnostic as distinctive metabolic patterns are specific for Alzheimer's disease (AD), dementia with Lewy bodies (DLB) and frontotemporal dementia (FTD). Previous studies have demonstrated that a data-driven decision model based on the disease state index (DSI) classifier supports clinicians in the differential diagnosis of dementia by using different combinations of diagnostic tests and biomarkers. Until now, this model has not included 2-[18F]FDG-PET data. The objective of the study was to evaluate 2-[18F]FDG-PET biomarkers combined with commonly used diagnostic tests in the differential diagnosis of dementia using the DSI classifier. We included data from 259 subjects diagnosed with AD, DLB, FTD, vascular dementia (VaD), and subjective cognitive decline from two independent study cohorts. We also evaluated three 2-[18F]FDG-PET biomarkers (anterior vs. posterior index (API-PET), occipital vs. temporal index, and cingulate island sign) to improve the classification accuracy for both FTD and DLB. We found that the addition of 2-[18F]FDG-PET biomarkers to cognitive tests, CSF and MRI biomarkers considerably improved the classification accuracy for all pairwise comparisons of DLB (balanced accuracies: DLB vs. AD from 64% to 77%; DLB vs. FTD from 71% to 92%; and DLB vs. VaD from 71% to 84%). The two 2-[18F]FDG-PET biomarkers, API-PET and occipital vs. temporal index, improved the accuracy for FTD and DLB, especially as compared to AD. Moreover, different combinations of diagnostic tests were valuable to differentiate specific subtypes of dementia. In conclusion, this study demonstrated that the addition of 2-[18F]FDG-PET to commonly used diagnostic tests provided complementary information that may help clinicians in diagnosing patients, particularly for differentiating between patients with FTD, DLB, and AD.

Case of posterior cortical atrophy (PCA) evolved to PCA-CBS.

A 68-year-old lawyer developed insidious disturbances in topographic orientation and apraxia. He underwent a geriatric evaluation, only documenting slight cognitive disturbances, and a 18F-fluorodeoxyglucose positron emission tomography (FDG-PET), showing mild right-lateralised frontoparietal hypometabolism. After 1 year, because of worsening in spatial orientation and the onset of dressing apraxia, he was referred to our memory clinic. The neuropsychological evaluation documented proeminent visuospatial, praxis deficits and dysgraphia. Cerebrospinal fluid biomarker analysis showed mild increase of total-τ, with normal Aß1-42, ruling out Alzheimer's disease. Progression of the right parietal hypometabolism at FDG-PET and right superior longitudinal fasciculus damage at high-field MRI revealed a probable neurodegenerative aetiology. The neurological examination disclosed then Gerstmann's and Balint's syndromes, and extrapyramidal signs later appeared, suggesting the diagnosis of posterior cortical atrophy associated with corticobasal syndrome. Genetic analysis for mutations inmicrotubule-associated protein tau (MAPT), C9orf72 and GRN genes was negative. A 1-year follow-up documented significant worsening of the cognitive and functional impairment, revealing a frank dementia.