title: Imaging and identification of brown adipose tissue on CT scan.
abstract: Two types of adipose tissue (AT) have been described in the field of physiology: white (W) and brown (B) AT. Although WAT is well identified on human imaging, BAT imaging aspect remains to be further explored. The aim of this study was to investigate imaging aspect of BAT and its identification on CT (computed tomography) with iodine-based contrast media injection. We retrospectively reviewed 464 positron emission tomography (PET)/CT, performed during 21 months on adults younger than 37 years. In 39 cases only, the PET revealed the presence of activated BAT. ROI was placed on both white and brown adipose tissue simultaneously on both PET and CT. Several patients' characteristics (blood sugar level, gender, age, body mass index) as well as BAT and WAT parameters were assessed. Mean CT densities for WAT and BAT were -99·5 HU versus -32·6, mean SUV were 1·38 versus 13·2 and SUVmax were 1·79 versus 16·57, respectively. We found a statistically significant inverse relation between BMI and BAT density. BAT has a higher density than WAT. In this manner, BAT can be misinterpreted as an infiltration of adipose tissue in neoplasic and inflammatory context. Contrast-enhanced CT scan allows visualization and identification of BAT.
authors.affiliation: Department of Medical Imaging, University Hospital of Brest, Brest, France.
authors.forename: Hugo
authors.initials: H
authors.lastname: Prodhomme
authors.affiliation: Department of Medical Imaging, University Hospital of Brest, Brest, France.
authors.forename: Julien
authors.initials: J
authors.lastname: Ognard
authors.affiliation: Department of Nuclear Medicine, University Hospital of Brest, Brest, France.
authors.forename: Philippe
authors.initials: P
authors.lastname: Robin
authors.affiliation: INSERM, CIC 1412, University Hospital of Brest, Brest, France.
authors.forename: Zarrin
authors.initials: Z
authors.lastname: Alavi
authors.affiliation: Department of Nuclear Medicine, University Hospital of Brest, Brest, France.|EA3878 GETBO, IFR 148, European University of Brittany, Brest, France.
authors.forename: Pierre-Yves
authors.initials: PY
authors.lastname: Salaun
authors.affiliation: Department of Medical Imaging, University Hospital of Brest, Brest, France.|LaTIM - INSERM UMR 1101, European University of Brittany, Brest, France.
authors.forename: Douraied
authors.initials: D
authors.lastname: Ben Salem
mesh_terms: D002001:Adipose Tissue, Brown / Q000000981:diagnostic imaging* / Q000502:physiology; D052436:Adipose Tissue, White / Q000000981:diagnostic imaging / Q000502:physiology; D050154:Adiposity; D000293:Adolescent; D000328:Adult; D005260:Female; D006801:Humans; D008297:Male; D000072078:Positron Emission Tomography Computed Tomography; D011237:Predictive Value of Tests; D012189:Retrospective Studies; D055815:Young Adult
keywords: 
  FDG
  ; PET/CT; brown fat; hounsfield units; supraclavicular area