Brown fat depots in adult humans remain static in their locations on PET/CT despite changes in seasonality (original) (raw)
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Characterizing Active and Inactive Brown Adipose Tissue in Adult Humans Using PET-CT and MR Imaging
American journal of physiology. Endocrinology and metabolism, 2016
Activated brown adipose tissue (BAT) plays an important role in thermogenesis and whole-body metabolism in mammals. Positron emission tomography (PET)-computed tomography (CT) imaging has identified depots of BAT in adult humans, igniting scientific interest. The purpose of this present study is to characterize both active and inactive supraclavicular BAT in adults, and compare the values to those of subcutaneous white adipose tissue (WAT). We obtained (18)F-fluorodeoxyglucose ((18)F-FDG) PET-CT and magnetic resonance imaging (MRI) scans of 25 healthy adults. Unlike (18)F-FDG PET, which can only detect active BAT, MRI is capable of detecting both active and inactive BAT. The MRI derived fat-signal fraction (FSF) of active BAT was significantly lower than inactive BAT (mean ± SD): 60.2 ± 7.6% vs. 62.4 ± 6.8%, respectively. This change in tissue morphology was also reflected as a significant increase in Hounsfield Units (HU): -69.4 ± 11.5 HU vs. -74.5 ± 9.7 HU, respectively. Additiona...
EJNMMI Research
Background Brown adipose tissue (BAT) is a thermogenic tissue which can generate heat in response to mild cold exposure. As it constitutes a promising target in the fight against obesity, we need reliable techniques to quantify its activity in response to therapeutic interventions. The current standard for the quantification of BAT activity is [18F]FDG PET/CT. Various sequences in magnetic resonance imaging (MRI), including those measuring its relative fat content (fat fraction), have been proposed and evaluated in small proof-of-principle studies, showing diverging results. Here, we systematically compare the predictive value of adipose tissue fat fraction measured by MRI to the results of [18F]FDG PET/CT. Methods We analyzed the diagnostic reliability of MRI measured fat fraction (FF) for the estimation of human BAT activity in two cohorts of healthy volunteers participating in two prospective clinical trials (NCT03189511, NCT03269747). In both cohorts, BAT activity was stimulated...
EJNMMI Research
Background Positron emission tomography (PET) is increasingly applied for in vivo brown adipose tissue (BAT) research in healthy volunteers. To limit the radiation exposure, the injected 18F-FDG tracer dose should be as low as possible. With simultaneous PET/MR imaging, the radiation exposure due to computed tomography (CT) can be avoided, but more importantly, the PET acquisition time can often be increased to match the more extensive magnetic resonance (MR) imaging protocol. The potential gain in detected coincidence counts, due to the longer acquisition time, can then be applied to decrease the injected tracer dose. The aim of this study was to investigate the minimal 18F-FDG dose for a 10-min time-of-flight (TOF) PET/MR acquisition that would still allow accurate quantification of supraclavicular BAT volume and activity. Methods Twenty datasets from 13 volunteers were retrospectively included from a prospective clinical study. PET emission datasets were modified to simulate step...
Cell Metabolism, 2016
Human brown adipose tissue (BAT) presence, metabolic activity, and estimated mass are typically measured by imaging [18F]fluorodeoxyglucose (FDG) uptake in response to cold exposure in regions of the body expected to contain BAT, using positron emission tomography combined with X-ray computed tomography (FDG-PET/CT). Efforts to describe the epidemiology and biology of human BAT are hampered by diverse experimental practices, making it difficult to directly compare results among laboratories. An expert panel was assembled by the National Institute of Diabetes and Digestive and Kidney Diseases on November 4, 2014 to discuss minimal requirements for conducting FDG-PET/CT experiments of human BAT, data analysis, and publication of results. This resulted in Brown Adipose Reporting Criteria in Imaging STudies (BARCIST 1.0). Since there are no fully validated best practices at this time, panel recommendations are meant to enhance comparability across experiments, but not to constrain experimental design or the questions that can be asked.
Hybrid PET/MRI as a tool to detect brown adipose tissue: Proof of principle
Obesity Research & Clinical Practice, 2015
Objective: The purpose of this study was to assess the performance of 18 F-FDG hybrid PET/MRI to detect and localise the presence of metabolically active brown adipose tissue (BAT). Methods: We retrospectively analyzed 197 consecutive 18 F-flurodeoxyglucose ( 18 F-FDG) positron-emission tomographic (PET) and magnetic resonance imaging (MRI) images performed with a hybrid whole-body PET-MRI tomography in 192 patients. These patients were originally investigated mainly for oncological staging, in the absence of a cooling protocol. The presence of BAT was defined as a soft tissue structure that was larger than 4 mm in diameter, had the characteristics of fat tissue on MRI and had a maximal standardised uptake value (SUV) of 18 F-FDG of at least 2.0. No specific MRI sequences for BAT detection were acquired. Results: PET/MRI identified the presence of metabolically active BAT in 5 out of 192 patients (2.6%). BAT positive subjects were all female, significantly younger and with significantly lower body weight than BAT negative subjects. Conclusions: Whole body hybrid PET/MRI allowed for the identification of BAT, with a low prevalence, comparable to previous retrospective PET/CT studies realised in the absence of a cooling protocol. The main advantages of the PET/MRI hybrid
Whole Body and Regional Quantification of Active Human Brown Adipose Tissue Using 18F-FDG PET/CT
Journal of Visualized Experiments, 2019
In endothermic animals, brown adipose tissue (BAT) is activated to produce heat for defending body temperature in response to cold. BAT's ability to expend energy has made it a potential target for novel therapies to ameliorate obesity and associated metabolic disorders in humans. Though this tissue has been well studied in small animals, BAT's thermogenic capacity in humans remains largely unknown due to the difficulties of measuring its volume, activity, and distribution. Identifying and quantifying active human BAT is commonly performed using 18 F-Fluorodeoxyglucose (18 F-FDG) positron emission tomography and computed tomography (PET/CT) scans following cold-exposure or pharmacological activation. Here we describe a detailed image-analysis approach to quantify total-body human BAT from 18 F-FDG PET/ CT scans using an open-source software. We demonstrate the drawing of user-specified regions of interest to identify metabolically active adipose tissue while avoiding common non-BAT tissues, to measure BAT volume and activity, and to further characterize its anatomical distribution. Although this rigorous approach is time-consuming, we believe it will ultimately provide a foundation to develop future automated BAT quantification algorithms.
Revista española de medicina nuclear
Brown adipose tissue (BAT) is a potential source of false-positive findings on [(18)F] FDG PET. In this report, we have discussed the (18)F-FDG uptake mechanisms in BAT and have aimed to determine if dual time point PET imaging helps to differentiate BAT from malignant lesions. Patients with dual-time-point PET/CT scans were reviewed retrospectively and 31 cases (11 males, 20 females, age: 28.6±9.7) having hypermetabolic BAT were included for this study. (18)F-FDG uptake in BAT was quantitatively analyzed by maximum standardized uptake values (SUVmax), and average percent change in SUVmax of BAT between early and delayed images was calculated. Compared to the initial scans, (18)F-FDG uptakes in BAT in delayed images were higher in 26 of the patients, and lower in one patient. In terms of body regions, (18)F-FDG uptake increased in 80.6%, remained unchanged in 5.5% and decreased in 13.9% of the body regions. Mean percent change in SUVmax, including all BAT regions, was 19.8±19.1% whi...
International Journal of Molecular Sciences
Obesity is a leading cause of preventable death and morbidity. To elucidate the mechanisms connecting metabolically active brown adipose tissue (BAT) and metabolic health may provide insights into methods of treatment for obesity-related conditions. 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18FDG-PET/CT) is traditionally used to image human BAT activity. However, the primary energy source of BAT is derived from intracellular fatty acids and not glucose. Beta-methyl-p-iodophenylpentadecanoic acid (BMIPP) is a fatty acid analogue amenable to in vivo imaging by single photon emission computed tomography/CT (SPECT/CT) when radiolabeled with iodine isotopes. In this study, we compare the use of 18FDG-PET/CT and 125I-BMIPP-SPECT/CT for fat imaging to ascertain whether BMIPP is a more robust candidate for the non-invasive evaluation of metabolically active adipose depots. Interscapular BAT, inguinal white adipose tissue (iWAT), and gonadal white adipose tissu...
Nuclear medicine and molecular imaging, 2013
To study the (18)F-FDG uptake pattern in brown adipose tissue (BAT) over an extended time period, by multiple-time-point fluorodeoxyglucose positron emission tomography (FDG-PET) imaging. The primary objective for this kind of research was that it could form a basis and may have further implications for obesity research, metabolic diseases and for cachexia of both malignant and benign origin. A total of 12 patients who had undergone routine FDG-PET for disease evaluation and had demonstrated prominent BAT uptake in their baseline scans were selected. The patients with the diagnosis of neuroendocrine tumors were excluded. Maximum standardized uptake values (SUVmax) were calculated in the BAT of the supraclavicular and paravertebral areas of either side, and were analyzed separately to examine their behavior individually. Time activity curves (TACs) were generated for [A] BAT SUVmax values and [B] SUVmax ratio of BAT/lung (B/L SUVmax ratio) at various time points. Ten out of the 12 pa...