Background
18F‐2‐fluoro‐2‐deoxy‐D‐glucose (18F‐FDG) positron emission tomography/computed tomography (FDG‐PET/CT) imaging provides important information about the size and metabolic activity of ...lesions caused by Echinococcus multilocularis and is therefore recommended for the initial assessment and follow‐up of human alveolar echinococcosis (AE). The introduction of positron emission tomography/magnetic resonance imaging (PET/MRI) into clinical practice in affluent health care systems provides an alternative dual imaging modality, which has not yet been evaluated for AE.
Objective
Here, we describe the initial clinical experience with comparative PET/CT and PET/MR imaging in four human AE patients at an Austrian reference centre.
Results
PET/MR imaging showed comparable diagnostic capacity for liver lesions attributable to E. multilocularis infection, with a discrepancy only in the assessment of calcifications in one patient. Effective doses of radiation were 30.4–31 mSV for PET/CT, which were reduced in PET/MRI to the exposure of 18F‐FDG only (4.9–5.5 mSv).
Conclusions
PET/MRI provides comparable diagnostic information for AE management. The reduction in radiation exposure compared to PET/CT may be of particular importance for children and young patients not amenable for curative surgery requiring repeated long‐term follow‐up with dual imaging modalities. Further studies are warranted to prospectively evaluate the potential of PET/MRI in the management of AE.
Données de base
L'imagerie par la tomographie par émission de positrons au 18F‐2‐fluoro‐2‐désoxy‐D‐glucose (18F‐FDG)/tomodensitométrie (TEP/TDM) fournit des informations importantes sur la taille et l'activité métabolique des lésions causées par Echinococcus multilocularis et est donc recommandée pour l’évaluation initiale et le suivi de l’échinococcose alvéolaire (EA) humaine. L'introduction de la tomographie par émission de positons/imagerie par résonance magnétique (TEP/IRM) dans la pratique clinique des systèmes de soins de santé aisés offre une alternative de modalité d'imagerie double, qui n'a pas encore été évaluée pour l’EA.
Objectif
Nous décrivons ici l'expérience clinique initiale comparant les imageries TEP/TDM et TEP/IRM chez quatre patients humains atteints d’EA dans un centre de référence autrichien.
Résultats
L'imagerie TEP/IRM a montré une capacité de diagnostic comparable pour les lésions hépatiques imputables à une infection à E. multilocularis, avec une divergence uniquement lors de l’évaluation des calcifications chez un patient. Les doses efficaces de rayonnement étaient de 30,4 à 31 mSV pour la TEP/TDM, qui ont été réduites dans la TEP/IRM à une exposition au 18F‐FDG uniquement (4,9 à 5,5 mSv).
Conclusions
La TEP/IRM fournit des informations de diagnostic comparables pour la prise en charge de l’EA. La réduction de l'exposition aux rayonnements comparée à la TEP/TDM pourrait avoir une importance particulière pour les enfants et les jeunes patients ne pouvant pas subir de chirurgie curative nécessitant un suivi répété à long terme avec des modalités de double imagerie. Des études supplémentaires sont nécessaires pour évaluer de manière prospective le potentiel de la TEP/IRM dans la prise en charge de l’EA.
Aims
To investigate, for a given energy expenditure (EE) rise, the differential effects of glucagon infusion and cold exposure on brown adipose tissue (BAT) activation in humans.
Methods
Indirect ...calorimetry and supraclavicular thermography was performed in 11 healthy male volunteers before and after: cold exposure; glucagon infusion (at 23 °C); and vehicle infusion (at 23 °C). All volunteers underwent 18F‐fluorodeoxyglucose (18F‐FDG) positron emission tomography (PET)/CT scanning with cold exposure. Subjects with cold‐induced BAT activation on 18F‐FDG PET/CT (n = 8) underwent a randomly allocated second 18F‐FDG PET/CT scan (at 23 °C), either with glucagon infusion (n = 4) or vehicle infusion (n = 4).
Results
We observed that EE increased by 14% after cold exposure and by 15% after glucagon infusion (50 ng/kg/min; p < 0.05 vs control for both). Cold exposure produced an increase in neck temperature (+0.44 °C; p < 0.001 vs control), but glucagon infusion did not alter neck temperature. In subjects with a cold‐induced increase in the metabolic activity of supraclavicular BAT on 18F‐FDG PET/CT, a significant rise in the metabolic activity of BAT after glucagon infusion was not detected. Cold exposure increased sympathetic activation, as measured by circulating norepinephrine levels, but glucagon infusion did not.
Conclusions
Glucagon increases EE by a similar magnitude compared with cold activation, but independently of BAT thermogenesis. This finding is of importance for the development of safe treatments for obesity through upregulation of EE.
About 25 % of new-onset epilepsies are diagnosed after age 65. Late-onset epilepsy (LOE) is predicted to become a major healthcare problem in the next 15 years as the global population increases and ...ages. Neurodegenerative disorders account for 10–20 % of LOE, while over 20 % of these patients have an unknown etiology. Established diagnostic tools such as FDG-PET and novel biomarkers of neurodegeneration including amyloid and tau PET hold a lot of promise in diagnosing and ruling out neurodegenerative disorders in these patients.
We conducted a literature search to identify articles involving LOE populations and using one or more functional neuroimaging techniques.
A total of 5 studies were identified through Boolean searching and snowballing. These were highly heterogenous with respect to operational definitions of LOE, analyses and interpretation pipelines.
While there is some evidence for feasibility and usefulness of FDG- and Amyloid PET in LOE, methodological heterogeneities in the available literature preclude any notable conclusions. Future research in this field will benefit from a consensus on epilepsy-specific analysis and interpretation guidelines for amyloid and tau PET.
In mouse models of dengue virus (DENV) infection, 18F-FDG PET is able to sensitively detect tissue-specific sites of inflammation and disease activity, as well as track therapeutic response to anti- ...DENV agents. However, the use of 18F-FDG PET to study the pathogenesis of inflammation and disease activity in DENV infection in humans, has not been clinically validated. Here we report the 18F-FDG PET imaging results of two patients during the febrile phase of acute DENV infection, paired with serial serum viral load, NS1 and proinflammatory cytokine measurements. Our findings demonstrate that 18F-FDG PET is able to sensitively detect and quantify organ-specific inflammation in the lymph nodes and spleen, in classic acute dengue fever. This raises the potential for 18F-FDG PET to be used as a research tool that may provide further insights into disease pathogenesis.
•The use of 18F-FDG PET to study the pathogenesis of dengue in humans has not been clinically validated.•18F-FDG PET imaging was performed in two patients with dengue fever, during acute infection and at convalescence.•In acute classic dengue fever, there is increased 18F-FDG uptake in the lymph nodes and spleen.•18F-FDG PET is a potential tool to study dengue pathogenesis and for the evaluation of therapeutics in clinical trials.
•The SUVmax of 18F-FDG was significantly correlated with PD-L1.•PD-L1 expression, and SUVmax were independent prognostic factors for OS.•For patients with high SUVmax, PD-L1 was an independent ...prognostic factor.
2-Deoxy-2-fluorine-18 fluoro-d-glucose with positron emission tomography (18F-FDG-PET) is a clinically useful tool for cancer evaluation. 18F-FDG accumulation in tumor cells is known to be correlated with the presence of glucose transporter 1 (GLUT1) and hypoxia-inducible factor-1α (HIF-1α). Although anti-programmed death-1 (PD-1) antibody treatments have been approved, no suitable predictor of significant responders has been identified. Based on the existing information, we investigated the relationship between tumor immunity (including PD-L1) and 18F-FDG uptake in patients with surgically resected pulmonary squamous-cell carcinoma (SQC).
This study included 167 patients (153 men and 14 women) with SQC who underwent 18F-FDG PET. Tumor sections were stained by immunohistochemistry for GLUT1, HIF-1α, PD-L1, CD4, CD8, and Foxp3. The relationship between clinicopathological features and 18F-FDG uptake was analyzed. Student’s t-test, the χ2 test, non-parametric Spearman’s rank test and the Kaplan–Meier method were used to show associations between variables.
The rate of positive PD-L1 expression was 79% (132/167), and PD-L1 expression was significantly associated with GLUT1 (P < 0.01), HIF-1α (P < 10−4), and CD8 (P < 1 × 10−3) expression. The SUVmax of 18F-FDG was significantly correlated with PD-L1 (P = 0.02) and GLUT1 (P < 0.01) expression. Multivariate analysis demonstrated that advanced stage, elevated PD-L1 expression, and elevated SUVmax were independent prognostic factors for predicting poor OS. Among patients with a high SUVmax, multivariate analysis confirmed that advanced stage and high PD-L1 expression were independent prognostic factors for poor OS; however, there was no significant difference among patients with a low SUVmax.
High SUVmax on 18F-FDG-PET is associated with PD-L1 expression but is an independent prognostic factor for OS in our population of surgically resected pulmonary squamous-cell carcinoma.
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•Role of 18FDG-PET in diagnosis (T), staging (N/M) and relapse of BTC was assessed.•18FDG-PET is not recommended for diagnosis (T) in the absence of cytology/histology.•18FDG-PET ...should be incorporated into current guidelines for staging (N/M) and relapse.•18FDG-PET should be used for staging (N/M) if identification of occult sites of disease will alter management.•18FDG-PET should be used to identify relapse if suspicion remains following standard imaging.
The role of 18F-fluorodeoxyglucose positron emission tomography (18FDG-PET) in the diagnosis and staging of patients with biliary tract cancers (BTCs) remains controversial, so we aimed to provide robust information on the utility of 18FDG-PET in the diagnosis and management of BTC.
This systematic review and meta-analysis explored the diagnostic test accuracy of 18FDG-PET as a diagnostic tool for diagnosis of primary tumour, lymph node invasion, distant metastases and relapsed disease. Subgroup analysis by study quality and BTC subtype were performed. Changes in management based on 18FDG-PET and impact of maximum standardised uptake values (SUVmax) on prognosis were also assessed. A random effects model was used for meta-analyses.
A total of 2,125 patients were included from 47 eligible studies. The sensitivity (Se) and specificity (Sp) of 18FDG-PET for the diagnosis of primary tumour were 91.7% (95% CI 89.8–93.2) and 51.3% (95% CI 46.4–56.2), respectively, with an area under the curve (AUC) of 0.8668. For lymph node invasion, Se was 88.4% (95% CI82.6–92.8) and Sp was 69.1% (95% CI 63.8–74.1); AUC 0.8519. For distant metastases, Se was 85.4% (95% CI 79.5–90.2) and Sp was 89.7% (95% CI86.0–92.7); AUC 0.9253. For relapse, Se was 90.1% (95% CI 84.4–94.3) and Sp was 83.5% (95% CI 74.4–90.4); AUC 0.9592. No diagnostic threshold effect was identified. Meta-regression did not identify significant sources of heterogeneity. Sensitivity analysis revealed no change in results when analyses were limited to studies with low risk of bias/concern. The pooled proportion of change in management was 15% (95% CI 11–20); the majority (78%) due to disease upstaging. Baseline high SUVmax was associated with worse survival (pooled hazard ratio of 1.79; 95% CI 1.37–2.33; p <0.001).
There is evidence to support the incorporation of 18FDG-PET into the current standard of care for the staging (lymph node and distant metastases) and identification of relapse in patients with BTC to guide treatment selection; especially if the identification of occult sites of disease would change management, or if diagnosis of relapse remains unclear following standard of care imaging. The role for diagnosis of the primary tumour remains controversial due to low sensitivity and 18FDG-PET should not be considered as a replacement for pathological confirmation in this setting.
A positron emission tomography (PET scan), using 18F-fluorodeoxyglucose (18FDG), can help doctors identify areas of cancer in the body by highlighting “hot spots”. These hotspots may be cancerous (true positive) but may also be non-cancerous, like inflammation (false positive). We show that PET scans are useful to assess how far advanced the cancer is (by assessing spread to lymph glands and to other organs) and also to identify if the cancer has recurred (for example after surgery), thus helping doctors to make treatment decisions. However, a biopsy is still needed for the initial diagnosis of a biliary tract cancer, because of the high chance of a “false positive” with PET scans.
Observational multimodal neuroimaging studies indicate sex differences in Alzheimer's disease pathophysiological markers.
Positron emission tomography brain amyloid load, neurodegeneration ...(hippocampus and basal forebrain volumes adjusted to total intracranial volume, cortical thickness, and 2-deoxy-2-fluorine-18fluoro-D-glucose–positron emission tomography metabolism), and brain resting-state functional connectivity were analyzed in 318 cognitively intact older adults from the INSIGHT-preAD cohort (female n = 201, male n = 117). A linear mixed-effects model was performed to investigate sex effects and sex∗apolipoprotein E genotype interaction on each marker as well as sex∗amyloid group interaction for non-amyloid markers.
Men compared with women showed higher anterior cingulate cortex amyloid load (P = .009), glucose hypometabolism in the precuneus (P = .027), posterior cingulate (P < .001) and inferior parietal (P = .043) cortices, and lower resting-state functional connectivity in the default mode network (P = .024). No brain volumetric markers showed differences between men and women. Sex∗apolipoprotein E genotype and sex∗amyloid status interactions were not significant.
Our findings suggest that cognitively intact older men compared with women have higher resilience to pathophysiological processes of Alzheimer's disease.
•Men have higher amyloid in the anterior cingulate cortex than women.•Men showed brain glucose hypometabolism compared to women with same global cognition.•Lower DMN resting-state functional connectivity was found in men compared to women.•Sex effects were independent from the APOE genotype and the amyloid status.•Our findings suggest higher brain resilience in men compared to women.
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