title: Is It Possible to Detect Activated Brown Adipose Tissue in Humans Using Single-Time-Point Infrared Thermography under Thermoneutral Conditions? Impact of BMI and Subcutaneous Adipose Tissue Thickness.
abstract: OBJECTIVE
  To evaluate the feasibility to detect activated brown adipose tissue (BAT) using single-time-point infrared thermography of the supraclavicular skin region under thermoneutral conditions. To this end, infrared thermography was compared with 18-F-FDG PET, the current reference standard for the detection of activated BAT.
  
  
  METHODS
  120 patients were enrolled in this study. After exclusion of 18 patients, 102 patients (44 female, 58 male, mean age 58±17 years) were included for final analysis. All patients underwent a clinically indicated 18F-FDG-PET/CT examination. Immediately prior to tracer injection skin temperatures of the supraclavicular, presternal and jugular regions were measured using spatially resolved infrared thermography at room temperature. The presence of activated BAT was determined in PET by typical FDG uptake within the supraclavicular adipose tissue compartments. Local thickness of supraclavicular subcutaneous adipose tissue (SCAT) was measured on CT. Measured skin temperatures were statistically correlated with the presence of activated BAT and anthropometric data.
  
  
  RESULTS
  Activated BAT was detected in 9 of 102 patients (8.8%). Local skin temperature of the supraclavicular region was significantly higher in individuals with active BAT compared to individuals without active BAT. However, after statistical correction for the influence of BMI, no predictive value of activated BAT on skin temperature of the supraclavicular region could be observed. Supraclavicular skin temperature was significantly negatively correlated with supraclavicular SCAT thickness.
  
  
  CONCLUSIONS
  We conclude that supraclavicular SCAT thickness influences supraclavicular skin temperature and thus makes a specific detection of activated BAT using single-time-point thermography difficult. Further studies are necessary to evaluate the possibility of BAT detection using alternative thermographic methods, e.g. dynamic thermography or MR-based thermometry taking into account BMI as a confounding factor.
authors.affiliation: University of Tübingen, Department of Radiology, Diagnostic and Interventional Radiology, Tübingen, Germany.
authors.forename: Sergios
authors.initials: S
authors.lastname: Gatidis
authors.affiliation: University of Tübingen, Department of Radiology, Diagnostic and Interventional Radiology, Tübingen, Germany.
authors.forename: Holger
authors.initials: H
authors.lastname: Schmidt
authors.affiliation: University of Tübingen, Department of Radiology, Diagnostic and Interventional Radiology, Tübingen, Germany.
authors.forename: Christina A
authors.initials: CA
authors.lastname: Pfannenberg
authors.affiliation: University of Tübingen, Department of Radiology, Diagnostic and Interventional Radiology, Tübingen, Germany.
authors.forename: Konstantin
authors.initials: K
authors.lastname: Nikolaou
authors.affiliation: University of Tübingen, Department of Radiology, Section for Experimental Radiology, Tübingen, Germany.
authors.forename: Fritz
authors.initials: F
authors.lastname: Schick
authors.affiliation: University of Tübingen, Department of Radiology, Diagnostic and Interventional Radiology, Tübingen, Germany.
authors.forename: Nina F
authors.initials: NF
authors.lastname: Schwenzer
mesh_terms: D002001:Adipose Tissue, Brown / Q000000981:diagnostic imaging*; D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015992:Body Mass Index; D005240:Feasibility Studies; D005260:Female; D019788:Fluorodeoxyglucose F18 / Q000737:chemistry; D006801:Humans; D007259:Infrared Rays; D008297:Male; D008875:Middle Aged; D049268:Positron-Emission Tomography; D019275:Radiopharmaceuticals / Q000737:chemistry; D012881:Skin Temperature; D050151:Subcutaneous Fat / Q000502:physiology*; D013817:Thermography; D014057:Tomography, X-Ray Computed; D055815:Young Adult
chemical_list: D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18