Identification of Brown Adipose Tissue Using MR Imaging in a Human Adult With Histological and Immunohistochemical Confirmation

Abstract

Manipulation of human brown adipose tissue (BAT) represents a novel therapeutic option for diabesity. The aim of our study was to develop and test a novel magnetic resonance (MR) imaging-based method to identify human BAT, delineate it from white adipose tissue, and validate it through immunohistochemistry. A 25-year old Caucasian female with hyperparathyroidism-jaw tumor syndrome underwent parathyroidectomy. An (18)fluoro-2-deoxyglucose positron emission tomography (PET)-computed tomography (CT) scan performed after surgery ruled out malignancy but showed avid uptake within the mediastinum, neck, supraclavicular fossae, and axillae, consistent with BAT. Immunohistochemical staining using uncoupling protein-1 antibody was performed on one fat sample obtained from the suprasternal area during parathyroidectomy. Subsequently, serial MR scans were performed. Retrospectively, regions of interest (ROIs) were identified on MR corresponding to areas of high uptake on PET-CT. Prospectively, ROIs were identified on MR based on signal intensity and appearance and compared with PET-CT. Of 111 retrospectively identified ROIs from PET-CT, 93 (83.8%) showed corresponding low MR signal: 25 of 25 mediastinum (100%), 29 of 31 neck (93.5%), 31 of 41 supraclavicular (75.6%), and 8 of 14 axillae (57%). Prospectively, 47 of 54 ROIs identified on MR (87%) showed a corresponding increased uptake on PET-CT. Serendipitously, the sample obtained at surgery corresponded with high uptake and low signal on subsequent PET and MR, respectively, and immunohistochemistry confirmed BAT. We provide the first report for the reliable use of MR to identify BAT in a living human adult, with histological/immunohistochemical confirmation. Our data demonstrate proof of concept to support the development of MR as a safe, reproducible imaging modality for human BAT.