title: Benzodiazepine-resistant "brown fat" pattern in positron emission tomography: two case reports of resolution with temperature control.
abstract: OBJECTIVE
  Supraclavicular uptake of 2-deoxy-2-[18F]fluoro-D-glucose (FDG) on positron emission tomography (PET) scan is attributed to lymph node, muscle, or brown fat activity. Differentiation between physiological or pathological etiologies is necessary. Benzodiazepine premedication to reduce physiological uptake has been attempted with variable success. A relationship between brown-fat FDG uptake and cold temperature has also been established. To our knowledge, no case reports or studies have been published to demonstrate whether controlling the temperature can alter the physiological uptake in these regions.
  
  
  METHODS
  Two teenage female patients with these patterns on PET scans performed with oral benzodiazepine administration underwent repeat imaging with temperature-controlled environment settings.
  
  
  RESULTS
  Resolution of supraclavicular FDG uptake with temperature control in two patients in whom benzodiazepine had no prior effect.
  
  
  CONCLUSIONS
  Although the exact mechanism remains unknown, we propose that the control of temperature reduces the metabolism of glucose by brown fat. Further studies are warranted to confirm the above observations, and, if confirmed, to determine the most efficient and effective use of temperature control to minimize supraclavicular and axillary FDG uptake.
authors.affiliation: Division of Nuclear Medicine, Washington Hospital Center, Washington, DC 20010, USA. carlos.garcia@medstar.net
authors.forename: Carlos A
authors.initials: CA
authors.lastname: Garcia
authors.forename: Douglas
authors.initials: D
authors.lastname: Van Nostrand
authors.forename: Massoud
authors.initials: M
authors.lastname: Majd
authors.forename: Francis
authors.initials: F
authors.lastname: Atkins
authors.forename: Elmo
authors.initials: E
authors.lastname: Acio
authors.forename: Anwer
authors.initials: A
authors.lastname: Sheikh
authors.forename: Calvin
authors.initials: C
authors.lastname: Butler
mesh_terms: D002001:Adipose Tissue, Brown / Q000000981:diagnostic imaging* / Q000187:drug effects* / Q000378:metabolism; D000293:Adolescent; D001569:Benzodiazepines / Q000008:administration & dosage / Q000494:pharmacology*; D001692:Biological Transport / Q000187:drug effects; D004351:Drug Resistance; D005260:Female; D019788:Fluorodeoxyglucose F18 / Q000378:metabolism; D005947:Glucose / Q000378:metabolism; D006689:Hodgkin Disease / Q000000981:diagnostic imaging* / Q000378:metabolism*; D006801:Humans; D049268:Positron-Emission Tomography; D013696:Temperature
chemical_list: D019788:Fluorodeoxyglucose F18; D001569:Benzodiazepines; D005947:Glucose