Characteristic Muscular FDG Uptake Patterns Related to the Transportation Means Used by Patients to Visit the Hospital.

ABSTRACT: It is well-known that physiological FDG uptake in the skeletal muscles is affected by serum insulin levels and the extent to which the muscles contract before the examination. Patients are instructed to refrain from strenuous exercise, talking too much, and taking meals at least 4 hours before the administration of the tracer. Even if the patient does not intend to exercise, muscular accumulation related to specific behaviors can still be visualized in the images. In this manuscript, we present FDG PET/CT images from 4 cases reflecting the mode of transportation used by the patients to visit the hospital.

The diagnostic and prognostic role of combined [18F]FDG and [68Ga]-DOTA-peptides PET/CT in primary pulmonary carcinoids: a multicentric experience.

OBJECTIVES: In the present retrospective multicentric study, we combined [68Ga]-DOTA-peptides and [18F]FDG-PET/CT findings aiming to investigate their capability to differentiate typical (TC) and atypical pulmonary carcinoids (AC) and their prognostic role. METHODS: From three centers, 61 patients were retrospectively included. Based on a dual tracer combination we classified PET scans as score 1, [18F]FDG- and [68Ga]-DOTA-peptides negative; score 2, [68Ga]-DOTA-peptides positive and [18F]FDG-negative; score 3, [68Ga]-DOTA-peptides negative and [18F]FDG-positive; score 4, both tracers positive. Moreover, for each patient, the ratios of SUVmax on [68Ga]-DOTA-PET to that on [18F]FDG-PET were calculated (SUVr). RESULTS: Thirty-five patients had a final diagnosis of TC. Twenty-two TC (57%) had positive [68Ga]-DOTA-peptides PET; instead, 21/26 (81%) AC had positive [18F]FDG-PET/CT. On dual-tracer analysis, scores 1, 2, 3 and 4 were 13%, 20%, 43% and 24% for all populations; 17%, 26%, 20% and 37% for TC; 8%, 11%, 73% and 8% for AC. Median SUVr was significantly higher in TC than AC (6.4 vs. 0.4, p = 0.011). The best value of SUVr to predict the final diagnosis was 1.05 (AUC 0.889). Relapse or progression of disease happened in 17 patients (11 affected by AC) and death in 10 cases (7 AC). AC diagnosis, positive [18F]FDG-PET, negative DOTA-PET and dual tracer score were significantly correlated with PFS (p = 0.013, p = 0.033, p = 0.029 and p = 0.019), while only AC diagnosis with OS (p = 0.022). CONCLUSION: PET/CT findings had also a prognostic role in predicting PFS. Dual-tracer PET behavior may be used to predict the nature of pulmonary carcinoids and select the most appropriate management. KEY POINTS: • Combination of [18F]FDG and [68Ga]-DOTA-peptides PET/CT results may help to differentiate between atypical and typical lung carcinoids. • The SUVmax ratio between [18F]FDG and [68Ga]-DOTA-peptides PET may help to differentiate between atypical and typical lung carcinoids. • Histotype and PET/CT features have a prognostic impact on PFS.

Cannabidiol Treatment Improves Glucose Metabolism and Memory in Streptozotocin-Induced Alzheimer's Disease Rat Model: A Proof-of-Concept Study.

An early and persistent sign of Alzheimer's disease (AD) is glucose hypometabolism, which can be evaluated by positron emission tomography (PET) with 18F-2-fluoro-2-deoxy-D-glucose ([18F]FDG). Cannabidiol has demonstrated neuroprotective and anti-inflammatory properties but has not been evaluated by PET imaging in an AD model. Intracerebroventricular (icv) injection of streptozotocin (STZ) is a validated model for hypometabolism observed in AD. This proof-of-concept study evaluated the effect of cannabidiol treatment in the brain glucose metabolism of an icv-STZ AD model by PET imaging. Wistar male rats received 3 mg/kg of STZ and [18F]FDG PET images were acquired before and 7 days after STZ injection. Animals were treated with intraperitoneal cannabidiol (20 mg/kg-STZ-cannabidiol) or saline (STZ-saline) for one week. Novel object recognition was performed to evaluate short-term and long-term memory. [18F]FDG uptake in the whole brain was significantly lower in the STZ-saline group. Voxel-based analysis revealed a hypometabolism cluster close to the lateral ventricle, which was smaller in STZ-cannabidiol animals. The brain regions with more evident hypometabolism were the striatum, motor cortex, hippocampus, and thalamus, which was not observed in STZ-cannabidiol animals. In addition, STZ-cannabidiol animals revealed no changes in memory index. Thus, this study suggests that cannabidiol could be an early treatment for the neurodegenerative process observed in AD.

Enhanced Fear Memories and Altered Brain Glucose Metabolism (18F-FDG-PET) following Subanesthetic Intravenous Ketamine Infusion in Female Sprague-Dawley Rats.

Although women and men are equally likely to receive ketamine following traumatic injury, little is known regarding sex-related differences in the impact of ketamine on traumatic memory. We previously reported that subanesthetic doses of an intravenous (IV) ketamine infusion following fear conditioning impaired fear extinction and altered regional brain glucose metabolism (BGluM) in male rats. Here, we investigated the effects of IV ketamine infusion on fear memory, stress hormone levels, and BGluM in female rats. Adult female Sprague-Dawley rats received a single IV ketamine infusion (0, 2, 10, or 20 mg/kg, over a 2-h period) following auditory fear conditioning (three pairings of tone and footshock). Levels of plasma stress hormones, corticosterone (CORT) and progesterone, were measured after the ketamine infusion. Two days after ketamine infusion, fear memory retrieval, extinction, and renewal were tested over a three-day period. The effects of IV ketamine infusion on BGluM were determined using 18F-fluoro-deoxyglucose positron emission tomography (18F-FDG-PET) and computed tomography (CT). The 2 and 10 mg/kg ketamine infusions reduced locomotor activity, while 20 mg/kg infusion produced reduction (first hour) followed by stimulation (second hour) of activity. The 10 and 20 mg/kg ketamine infusions significantly elevated plasma CORT and progesterone levels. All three doses enhanced fear memory retrieval, impaired fear extinction, and enhanced cued fear renewal in female rats. Ketamine infusion produced dose-dependent effects on BGluM in fear- and stress-sensitive brain regions of female rats. The current findings indicate that subanesthetic doses of IV ketamine produce robust effects on the hypothalamic-pituitary-adrenal (HPA) axis and brain energy utilization that may contribute to enhanced fear memory observed in female rats.

Total Variation Constrained Graph Manifold Learning Strategy for Cerenkov Luminescence Tomography.

Harnessing the power and flexibility of radiolabeled molecules, Cerenkov luminescence tomography (CLT) provides a novel technique for non-invasive visualisation and quantification of viable tumour cells in a living organism. However, owing to the photon scattering effect and the ill-posed inverse problem, CLT still suffers from insufficient spatial resolution and shape recovery in various preclinical applications. In this study, we proposed a total variation constrained graph manifold learning (TV-GML) strategy for achieving accurate spatial location, dual-source resolution, and tumour morphology. TV-GML integrates the isotropic total variation term and dynamic graph Laplacian constraint to make a trade-off between edge preservation and piecewise smooth region reconstruction. Meanwhile, the tetrahedral mesh-Cartesian grid pair method based on the k-nearest neighbour, and the adaptive and composite Barzilai-Borwein method, were proposed to ensure global super linear convergence of the solution of TV-GML. The comparison results of both simulation experiments and in vivo experiments further indicated that TV-GML achieved superior reconstruction performance in terms of location accuracy, dual-source resolution, shape recovery capability, robustness, and in vivo practicability. Significance: We believe that this novel method will be beneficial to the application of CLT for quantitative analysis and morphological observation of various preclinical applications and facilitate the development of the theory of solving inverse problem.

El papel pronóstico del SUVmáx basal y cambio del SUVmáx en la PET/TC con18F-FDG en pacientes con cáncer de mama con ganglios positivos que reciben quimioterapia neoadyuvante / The prognostic role of baseline 18F-FDG PET/CT SUVmax and SUVmax change in patients with node-positive breast cancer receiving neoadjuvant chemotherapy

Objetivo: En este estudio, se tuvo como objetivo determinar el papel pronóstico del valor de captación máximo estandarizado (SUVmáx) basal obtenido por PET/TC antes del tratamiento, y el cambio en el SUVmáx (ΔSUVmáx [%]) en pacientes con cáncer de mama con ganglios linfáticos axilares positivos en tratamiento con quimioterapia neoadyuvante (NAC).Métodos: Se evaluaron en el estudio 180 pacientes con SUVmáx basal y 121 pacientes con medición de SUVmáx después del tratamiento. Se midieron el valor de SUVmáx inicial de la mama (SUVmáxBI) y axila (SUVmáxAI), y el cambio en el SUVmáx de la mama (ΔSUVmáxB) y axila (ΔSUVmáxA). El valor de corte óptimo de SUVmáx y ΔSUVmáx se determinó mediante el análisis de la curva ROC. La supervivencia libre de enfermedad (SSE) y la supervivencia global (SG) se calcularon mediante curvas de Kaplan-Meier.Resultados: Se encontró que los parámetros ΔSUVmáxB, pCRB, pCRA y pCR se asociaron con la recaída (p <0.001, p =0.033, p =0.016 y p =0.013, respectivamente). ΔSUVmáxB y SUVmáxAI se asociaron con la mortalidad (p=0,001 y p=0,006, respectivamente). El análisis de regresión de Cox múltiple reveló que el valor de ΔSUVmáxB era un factor pronóstico independiente para la recaída y la mortalidad (p = 0,013 y p = 0,010, respectivamente).Conclusión: Los resultados muestran que ΔSUVmáxB es un factor pronóstico independiente de recaída y mortalidad en pacientes con cáncer de mama con ganglios linfáticos axilares positivos que recibieron NAC (AU)

Objective: This study aimed to determine the prognostic role of baseline maximum standardized uptake value (SUVmax) obtained by pretreatment PET/CT and the change in SUVmax (ΔSUVmax [%]) in patients with axillary lymph node–positive breast cancer receiving neoadjuvant chemotherapy (NAC).Methods: One hundred and eighty patients with baseline SUVmax and 121 patients with SUVmax measurement after treatment were evaluated in the study. The baseline SUVmax value of the breast (SUVmaxBI) and axilla (SUVmaxAI) and the change in the SUVmax of the breast (ΔSUVmaxB) and axilla (ΔSUVmaxA) were measured. The optimal cut-off value of SUVmax and ΔSUVmax were determined by ROC curve analysis. Disease-free survival (DFS) and overall survival (OS) were calculated using Kaplan–Meier curves.Results: ΔSUVmaxB, pCRB, pCRA, and pCR parameters were found to be associated with relapse (p < 0.001, p = 0.033, p = 0.016, and p = 0.013, respectively). ΔSUVmaxB and SUVmaxAI were associated with mortality (p = 0.001 and p = 0.006, respectively). Multiple Cox regression analyses revealed that ΔSUVmaxB value was an independent prognostic factor for relapse and mortality (p = 0.013 and p = 0.010, respectively).Conclusion: The results showed that ΔSUVmaxB was an independent prognostic factor for relapse and mortality in patients with axillary lymph node–positive breast cancer who received NAC (AU)

Malignant prediction of incidental findings using ring-type dedicated breast positron emission tomography.

The classification according to uptake patterns and metabolic parameters on ring-type dedicated breast positron emission tomography (dbPET) is useful for detecting breast cancer. This study investigated the performance of dbPET for incidental findings that were not detected by mammography and ultrasonography. In 1,076 patients with breast cancer who underwent dbPET, 276 findings were incidentally diagnosed before treatment. Each finding was categorized as focus (uptake size ≤ 5 mm), mass (> 5 mm), or non-mass (multiple uptake) according to uptake patterns. Non-mass uptakes were additionally classified based on their distributions as-linear, focal, segmental, regional, or diffuse. Thirty-two findings (11.6%) were malignant and 244 (88.4%) were benign. Visually, 227 (82.3%) findings were foci, 7 (2.5%) were masses, and 42 (15.2%) were non-masses. Malignant rates of focus, mass, and non-mass were 9.7%, 28.6%, and 19.0%, respectively. In the non-mass findings, 23 were regional and diffuse distributions, and presented as benign lesions. Focus uptake with low lesion-to-background ratio (LBR) and no hereditary risk were relatively low (2.7%) in breast cancer. In multivariate analysis, LBR and hereditary risk were significantly associated with breast cancer (p = 0.006 and p = 0.013, respectively). Uptake patterns, LBR, and hereditary risk are useful for predicting breast cancer risk in incidental dbPET findings.

Metabolic tumour volume on 18F-FDG PET/CT predicts extended pathological T stages in patients with renal cell carcinoma at staging.

We evaluated the predictive value of 18F-fluorodeoxyglucose (FDG) uptake on positron emission tomography/CT (PET/CT) for extended pathological T (pT) stages (≥ pT3a) in Renal cell carcinoma (RCC) patients at staging. Thirty-eight RCC patients who underwent 18F-FDG PET/CT at staging, followed by radical nephrectomy between September 2016 and September 2018, were included in this prospective study. Patients were classified into two groups (limited pT stage: stage T1/2, n = 17; extended pT stage: T3/4, n = 21). Univariate and multivariate logistic regression analyses were performed to identify clinicopathological and metabolic variables to predict extended pT stages. 18F-FDG metabolic parameters were compared in relation to International Society of Urological Pathology (ISUP) grade and lymphovascular invasion (LVI). In univariate analysis, maximum standardised uptake value, metabolic tumour volume (MTV), and ISUP grade were significant. In multivariate analysis, MTV was the only significant factor of extended pT stages. With a cut-off MTV of 21.2, an area under the curve was 0.944, which was higher than 0.824 for clinical T stages (p = 0.037). In addition, high MTV, but not tumour size, was significantly correlated with aggressive pathologic features (ISUP grade and LVI). High glycolytic tumour volume on 18F-FDG PET/CT in RCC patients at staging is predictive of extended pT stages which could aid decision-making regarding the best type of surgery.

Current Role of Functional Imaging in the Management of Lymphoma.

PURPOSE OF REVIEW: Functional imaging with 18FDG-PET-CT has transformed the staging and response assessment of patients with Hodgkin (HL) and non-Hodgkin lymphoma (NHL). Herein, we review the current role and future directions for functional imaging in the management of patients with lymphoma. RECENT FINDINGS: Because of its increased sensitivity, PET-CT is the preferred modality for staging of FDG-avid lymphomas. It appears to have a role for interim assessment in patients with HL with adaptive strategies that reduce toxicity in lower risk patients and increase efficacy in those at high risk. Such a role has yet to be demonstrated in other histologies. FDG-PET-CT is also the gold standard for response assessment posttreatment. Newer uses include assessment of total metabolic tumor volume and radiomics in pretreatment prognosis. Whereas PET-CT is more sensitive than other current modalities for staging and response assessment, the future of PET-CT will be in conjunction with other modalities, notably assessment of minimal residual disease and microenvironmental markers to develop risk adaptive strategies to improve the outcome of patients with lymphoma.

Total lesion glycolysis as a predictor of clinical T3-4a laryngeal cancer with laryngectomy or nonlaryngectomy.

ABSTRACT: The purpose of the present study is to investigate whether the 18F-fluorodeoxyglucose (18F-FDG) uptake parameter is related to survival outcomes for patients with clinical T3-T4a laryngeal cancer with various definitive treatments including total laryngectomy (TL). Parameters of 18F-FDG uptake in the primary tumors of 46 cases which were assessed by positron emission tomography with computed tomography were enrolled in the present observation study. Monovariate or multivariate survival analyses were performed with log-rank test or Cox regression model, with the hazard ratio (HR) and 95% confidence interval (CI), respectively. Cutoff values of the 18F-FDG uptake parameters were determined by the lowest P-value for monovariate overall survival. In the monovariate analysis, both metabolic tumor volume ≥13.1 and total lesion glycolysis (TLG) ≥46.5 were significantly associated with shorter overall survival, and TLG ≥46.5 was also related to a reduction in distant metastasis-free survival. In the multivariate analysis adjusting for clinical T classification (cT4/cT3) and treatment group (TL/non-TL), TLG (≥46.5/<46.5) was associated with both poorer overall (HR: 3.16, 95% CI: 1.10-9.49) and distant metastasis-free (HR: 8.91, 95% CI: 1.93-62.6) survival. In conclusion, TLG is a predictor for survival in laryngeal cancer.

Impact of PET/CT among patients with suspected mycotic aortic aneurysms.

PURPOSE: To determine the impact of 18F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) on clinical management in patients with suspected mycotic aortic aneurysms (MAA). MATERIALS AND METHODS: For this observational cohort study 101 PET/CT were acquired in 50 patients, thereof 50 for the initial diagnosis/baseline scan, 51 for follow-up. Impact on patient management was defined in three categories: PET/CT results were "confirmed" (by clinical follow-up), "suspected" (conclusive, not confirmed), or "misleading" (proven wrong by follow-up). For clinical follow-up patient data were recorded at the time of imaging, and at the latest recorded clinical visit. It included patient demographics, clinical information, laboratory data, results of microbiology and other diagnostic procedures, information about treatment, and patient's general health condition. RESULTS: In four patients (8%) no clinical follow-up was feasible, the other 46 patients were clinically followed for a median of 898 days (IQR 320-4105). The combined evaluation of all 101 PET/CT demonstrated an impact on patient management in 78,5% of cases (48,5% confirmed, 30% suspected). Results of 21,5% of the PET/CT examinations were misleading. Respective values at baseline and at follow-up were: impact on patient management in 82% and 74,5% (70% and 27.5% confirmed, and 12% and 47% suspected), misleading cases in 18% and 25.5%. CONCLUSION: In MAA, PET/CT has a high impact on patient management, which is more pronounced with baseline than with follow-up examinations. However, PET/CT results may be misleading in a smaller proportion of cases.

Glucose Metabolic Alteration of Cerebral Cortical Subareas in Rats with Renal Ischemia/Reperfusion Based on Small-Animal Positron Emission Tomography.

OBJECTIVE: To investigate glucose metabolic alterations in cerebral cortical subareas using 18F-labeled glucose derivative fluorodeoxyglucose (FDG) micro-positron emission tomography (PET) scanning in a rat renal ischemia/reperfusion (RIR) model. METHODS: Small-animal PET imaging in vivo was performed with 18F-labeled FDG as a PET tracer to identify glucose metabolic alterations in cerebral cortical subregions using a rat model of RIR. RESULTS: We found that the average standardized uptake value (SUVaverage) of the cerebral cortical subareas in the RIR group was significantly increased compared to the sham group (P<0.05). We also found that glucose uptake in different cortical subregions including the left auditory cortex, right medial prefrontal cortex, right para cortex, left retrosplenial cortex, right retrosplenial cortex, and right visual cortex was significantly increased in the RIR group (P<0.05), but there was no significant difference in the SUVaverage of right auditory cortex, left medial prefrontal cortex, left para cortex, and left visual cortex between the two groups. CONCLUSION: The 18F-FDG PET data suggests that RIR causes a profound shift in the metabolic machinery of cerebral cortex subregions.

Fluorodeoxyglucose Positron-Emission Tomography/Computed Tomography and Magnetic Resonance Imaging for Adverse Local Tissue Reactions near Metal Implants after Total Hip Arthroplasty: A Preliminary Report.

BACKGROUND: Plain computed tomography (CT) and magnetic resonance imaging (MRI) are useful for diagnosing adverse local tissue reactions after metal-on-metal total hip arthroplasty (THA), but metal artifacts can hamper radiological assessments near the implants. We sought to clarify the usefulness of 18F-fluorodeoxyglucose positron-emission tomography (18F-FDG-PET) CT and MRI in the periprosthetic region, which is difficult to assess after THA due to metal artifacts. METHODS: We performed preoperative 18F-FDG-PET/CT and 18F-FDG-PET/MRI, as well as plain CT and MRI, in 11 metal-on-metal THA patients who underwent revision surgery. RESULTS: Most patients showed high FDG uptake in the metal artifact areas and pseudotumors in the 18-F-FDG-PET/CT and 18-F-FDG-PET/MRI scans. Intraoperative intra-articular macroscopic and histopathological intra-articular granulation tissue findings were suggestive of adverse local tissue reaction. CONCLUSIONS: The enhanced uptake in the metal artifact areas seemed to reflect adverse local tissue reaction. Therefore, 18F-FDG-PET/CT and 18-F-FDG-PET/MRI can be useful for the auxiliary diagnosis of adverse local tissue reactions after metal-on-metal THA.

Cytokine Signaling and Matrix Remodeling Pathways Associated with Cardiac Sarcoidosis Disease Activity Defined Using FDG PET Imaging.

While cardiac imaging has improved the diagnosis and risk assessment for cardiac sarcoidosis (CS), treatment regimens have consisted of generalized heart failure therapies and non-specific anti-inflammatory regimens. The overall goal of this study was to perform high-sensitivity plasma profiling of specific inflammatory pathways in patients with sarcoidosis and with CS.Specific inflammatory/proteolytic cascades were upregulated in sarcoidosis patients, and certain profiles emerged for CS patients.Plasma samples were collected from patients with biopsy-confirmed sarcoidosis undergoing F-18 fluorodeoxyglucose positron emission tomography (n = 47) and compared to those of referent control subjects (n = 6). Using a high-sensitivity, automated multiplex array, cytokines, soluble cytokine receptor profiles (an index of cytokine activation), as well as matrix metalloproteinase (MMP), and endogenous MMP inhibitors (TIMPs) were examined.The plasma tumor necrosis factor (TNF) and soluble TNF receptors sCD30 and sTNFRI were increased using sarcoidosis, and sTNFRII increased in CS patients (n = 18). The soluble interleukin sIL-2R and vascular endothelial growth factor receptors (sVEGFR2 and sVEGFR3) increased to the greatest degree in CS patients. When computed as a function of referent control values, the majority of soluble cytokine receptors increased in both sarcoidosis and CS groups. Plasma MMP-9 levels increased in sarcoidosis but not in the CS subset. Plasma TIMP levels declined in both groups.The findings from this study were the identification of increased activation of a cluster of soluble cytokine receptors, which augment not only inflammatory cell maturation but also transmigration in patients with sarcoidosis and patients with cardiac involvement.

Uso del filtro hidrofóbico estéril de 0, 2 micras para fraccionamiento y dispensación de fludesoxiglucosa (18f-fdg) en el dispensador automático con celda caliente de flujo laminar blindada con filtro hepa / Use of sterile 0, 2 micron hydrophobic filter for fractionation and dispensing of fludeoxyglucose (18f-fdg) in the automatic dispenser with laminar flow hot cell shielded with hepa filter

INTRODUCCIÓN: La tomografía por emisión de positrones (PET) es un examen imagenológico que a través de un scanner para PET, la inyección intravenosa de un radiomarcador o radiosonda nos permite realizar exploraciones para detectar cáncer o determinar si hubo metástasis, evaluar la efectividad del tratamiento contra el cáncer o su recurrencia y evaluar pronóstico. Dentro de los radiomarcadores utilizados para el uso de PET la fludesoxiglucosa (18F-FDG) es un análogo de la glucosa y se acumula en células que utilizan glucosa como fuente primaria de energía y sobre todo las células que tienen un alto intercambio de glucosa como las células oncológicas. Su síntesis se lleva a cabo a través de un equipo especial que requiere de otros insumos para poder lograr en la fase final el fraccionamiento y dispensación exacta de este marcador. Para ello se utilizan filtros hidrofóbicos los cuales son individuales y se colocan en la celda caliente del equipo. En INEN durante el 2021 se estuvieron realizando diariamente PETs en la nueva torre cuya inversión incluyó la adquisición del equipo para la síntesis, fraccionamiento y dispensación del 18F-FDG; sin embargo, actualmente ya no se cuenta con el filtro hidrofóbico que se coloca en el equipo y logra la fase final del procedimiento de obtención de 18F-FDG. Para el correcto funcionamiento se requerirían según lo coordinado con el área usuaria un promedio de 400 filtros adquiridos anualmente. METODOLOGÍA: Se realizó una búsqueda sistemática de la información y una búsqueda dirigida en las principales entidades que elaboran tecnologías sanitarias y guías relacionadas al tema. Con respecto a la búsqueda dirigida se encontró 02 guías de entidades reconocidas a nivel internacional, en una de ellas no se encontró información sobre el procedimiento de síntesis, pero en otra si se encontró y se especificaban las características y la importancia de contar con un filtro hidrofóbico que permita obtener una muestra estéril y fraccionada en cantidades exactas para el paciente. En la búsqueda sistemática se encontró 02 revisiones narrativas que mencionan la importancia de utilizar los filtros hidrofóbicos como parte de la calidad del procedimiento de síntesis del radiofármaco para PET. A pesar de que sean revisiones narrativas, en ambos casos se brinda información con respecto al fraccionamiento, dispensación, esterilidad y la necesidad de filtros hidrofóbicos para la protección del personal de salud que realiza el procedimiento. DISCUSIÓN: Se agregó información sobre el uso de tomografía por emisión de positrones. Este ambiente que incluye el equipo entro en funcionamiento cuando se apertura la torre nueva en INEN. Por ello, la adquisición de los equipos que participan para lograr un adecuado uso del TEM formaron parte del presupuesto del proyecto de la torre nueva y ello incluyo el equipo de celda caliente que tiene como dificultad la necesidad de usar un filtro exclusivo que permita el fraccionamiento y dispensación del radiofármaco usado para el TEM. Durante los primeros meses como se disponía del dispositivo se ha venido trabajando de manera normal; sin embargo, a la actualidad solamente se está usando el TEM cuando el paciente cuenta de manera personal con el radiofármaco (18F-FDG) ya fraccionado y en dosis exactas individualizadas. Por otro lado, si el INEN adquiriera el radiomarcador fraccionado el precio se eleva comparado a adquirirlo para fraccionar a nivel institucional y el fraccionar a nivel institucional permite un uso más racional de las dosis que vienen en un vial. CONCLUSIONES: Finalmente; a pesar de que no se cuente con evidencia de alta calidad con respecto a la utilidad de los filtros hidrofóbicos, la evidencia encontrada aboga por la necesidad de que se apruebe su adquisición debido a que es un dispositivo necesario dentro de la última etapa de dispensación y fraccionamiento del FDG18 y el correcto funcionamiento del equipo de celda caliente en INEN.

Tumor immunity is related to 18 F-FDG uptake in thymic epithelial tumor.

BACKGROUND: 2-deoxy-2-[fluorine-18] fluoro-d-glucose (18 F-FDG) positron emission tomography (18 F-FDG-PET) is a convenient modality to assess the metabolic activity within tumor cells. However, there is no consensus regarding the relationship between 18 F-FDG uptake and the immune environment in thymic epithelial tumors (TETs). We conducted a clinicopathological study to elucidate the relationship between 18 F-FDG uptake and programmed death ligands 1 and 2 (PD-L1/PD-L2) expression in patients with TETs. METHODS: A total of 108 patients with histologically confirmed TETs classified as thymomas or thymic carcinomas who underwent surgical resection or biopsy or needle biopsy and 18 F-FDG PET before any treatment between August 2007 and March 2020 were enrolled in this study. Tumor specimens underwent immunohistochemical staining for PD-L1, PD-L2, GLUT1, HIF-1α, VEGFR2, VEGF-C, and ß2 adrenergic receptor. RESULTS: High uptakes of SUVmax , SUVmean , MTV, and TLG were identified in 28 (25.9%), 61 (56.5%), 55 (50.9%), and 55 (50.9%) of 108 patients, respectively. High uptake of SUVmax significantly correlated with PS (performance status) of 1-2, thymic carcinoma, and advanced stage, and SUVmax on 18 F-FDG uptake displayed a close association with PD-L1 and PD-L2 expressions, but not with MTV and TLG. Our analysis revealed that SUVmax was identified as being significant relationship for positive PD-L1/PD-L2 expression. GLUT1, HIF-1α, and VEGFR2 were significantly associated with the expression of PD-L1/PD-L2 from the biological viewpoint. CONCLUSION: 18 F-FDG accumulation was closely associated with the expression of PD-L1/PD-L2, which, in turn, was correlated with glucose metabolism and hypoxia. PD-L1/PD-L2 could affect the glucose metabolism and hypoxia in thymic tumor cells.

Ischemic heart failure mortality is not predicted by cardiac insulin resistance but by diabetes per se and coronary flow reserve: A retrospective dynamic cardiac 18F-FDG PET study.

BACKGROUND & AIMS: The connection between peripheral insulin resistance (IR) and coronary artery disease is well-established. Both are major risk factors for the development of ischemic cardiomyopathy potentially leading to heart failure (HF). Whether cardiac IR also impacts overall survival and morbidity is still debated. We therefore aimed to test if cardiac IR predicts mortality and major cardiovascular events (MACE) in patients with HF scheduled for cardiac viability testing before revascularization. METHODS: This retrospective study included 131 patients with a clinical diagnosis of ischemic HF (114 (87%) male, 33 (25%) with diabetes) referred to a viability Rubidium-82 (perfusion) and dynamic 18F-Fluorodeoxyglucose (metabolism) positron emission tomography combined with computed tomography prior to a potential revascularization procedure. Cardiac IR was assessed by myocardial glucose uptake (MGU) in a remote (non-scarred) area of the left ventricle during a hyperinsulinemic-euglycemic clamp (1mIE/kg/min). RESULTS: MGU correlated with skeletal muscle glucose uptake (p < 0.001) and whole-body glucose uptake (M-value) (p < 0.001), whereas no association was observed for individuals with diabetes. MGU did not predict the risk of death or MACE. However, both overt diabetes and reduced coronary flow reserve predicted overall survival. CONCLUSION: Even though diabetes and related small-vessel disease is associated with increased mortality, cardiac IR per se does not predict cardiovascular morbidity and mortality.

PET/MRI of glucose metabolic rate, lipid content and perfusion in human brown adipose tissue.

This study evaluated the MRI-derived fat fraction (FF), from a Cooling-reheating protocol, for estimating the cold-induced brown adipose tissue (BAT) metabolic rate of glucose (MRglu) and changes in lipid content, perfusion and arterial blood volume (VA) within cervical-supraclavicular fat (sBAT). Twelve volunteers underwent PET/MRI at baseline, during cold exposure and reheating. For each temperature condition, perfusion and VA were quantified with dynamic [15O]water-PET, and FF, with water-fat MRI. MRglu was assessed with dynamic [18F]fluorodeoxyglucose-PET during cold exposure. sBAT was defined using anatomical criteria, and its subregion sBATHI, by MRglu > 11 µmol/100 cm3/min. For all temperature conditions, sBAT-FF correlated negatively with sBAT-MRglu (ρ ≤ - 0.87). After 3 h of cold, sBAT-FF decreased (- 2.13 percentage points) but tended to normalize during reheating although sBATHI-FF remained low. sBAT-perfusion and sBAT-VA increased during cold exposure (perfusion: + 5.2 ml/100 cm3/min, VA: + 4.0 ml/100 cm3). sBAT-perfusion remained elevated and sBAT-VA normalized during reheating. Regardless of temperature condition during the Cooling-reheating protocol, sBAT-FF could predict the cold-induced sBAT-MRglu. The FF decreases observed after reheating were mainly due to lipid consumption, but could potentially be underestimated due to intracellular lipid replenishment. The influence of perfusion and VA, on the changes in FF observed during cold exposure, could not be ruled out.