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Am J Nucl Med Mol Imaging 2011;1(1):29-35.
Original article
Intravenous administration of diazepam significantly reduces brown fat activity on
18F-FDG PET/CT
Rajan Rakheja, Anthony Ciarallo, Yazan Z Alabed, Marc Hickeson
Department of Nuclear Medicine, Royal Victoria Hospital, Montreal, Quebec, Canada
Received May 12, 2011; accepted June 10, 2011; Epub June 18, 2011; Published August 1, 2011
Abstract: Brown adipose tissue (BAT) activity on 18F-fluorodeoxyglucose (FDG) PET/CT can introduce an undesirable element of
complexity when attempting to discern physiologic activity from more ominous entities. Recent studies have demonstrated several
methods to reduce BAT FDG uptake. Benzodiazepines, however, have yet to been proven effective against BAT. Methods: Twenty-five
patients with increased BAT FDG uptake were selected retrospectively from our PET/CT database between November 2004 and
January 2011. These patients had been asked to return on a different day for repeat scanning with 5mg of intravenous diazepam,
administered ten minutes prior to FDG. Two patients underwent this procedure on a second occasion (for a follow-up scan at a later
date), thus resulting in a total of twenty-seven scans from twenty five patients. FDG uptake in BAT was recorded using the maximum
standardized uptake value (SUVmax). Results: The mean basal BAT SUVmax was 10.1 ± 4.6 compared to a mean SUVmax of 2.8 ±
3.3 post IV diazepam (p < 0.0001). Approximately 89% (24 of 27) of scans had no significant residual BAT activity. The three
remaining scans had a reduction in SUVmax ranging from 23-64% following diazepam administration. No adverse effects were
noted. Conclusion: We observed a significant reduction in brown fat activity in para-spinal, cervical, mediastinal, para-adrenal, and
supra- and infra-clavicular regions on PET/CT following premedication with intravenous diazepam. We feel that IV benzodiazepines
should be considered a pharmacologic option for reducing BAT FDG uptake, which in turn, will aid in distinguishing physiologic
metabolic activity from pathology. (ajnmmi1105002).
Keywords: Brown adipose tissue, diazepam, 18F-FDG PET
Full text PDF
Address all correspondence to:
Dr. Rajan Rakheja Royal
Victoria Hospital
687 Pine Avenue
Montreal, Quebec, Canada, H3A 1A1.
Tel: 514-295-6104
E-mail: rajan.rakheja@gmail.com
Original article
Intravenous administration of diazepam significantly reduces brown fat activity on
18F-FDG PET/CT
Rajan Rakheja, Anthony Ciarallo, Yazan Z Alabed, Marc Hickeson
Department of Nuclear Medicine, Royal Victoria Hospital, Montreal, Quebec, Canada
Received May 12, 2011; accepted June 10, 2011; Epub June 18, 2011; Published August 1, 2011
Abstract: Brown adipose tissue (BAT) activity on 18F-fluorodeoxyglucose (FDG) PET/CT can introduce an undesirable element of
complexity when attempting to discern physiologic activity from more ominous entities. Recent studies have demonstrated several
methods to reduce BAT FDG uptake. Benzodiazepines, however, have yet to been proven effective against BAT. Methods: Twenty-five
patients with increased BAT FDG uptake were selected retrospectively from our PET/CT database between November 2004 and
January 2011. These patients had been asked to return on a different day for repeat scanning with 5mg of intravenous diazepam,
administered ten minutes prior to FDG. Two patients underwent this procedure on a second occasion (for a follow-up scan at a later
date), thus resulting in a total of twenty-seven scans from twenty five patients. FDG uptake in BAT was recorded using the maximum
standardized uptake value (SUVmax). Results: The mean basal BAT SUVmax was 10.1 ± 4.6 compared to a mean SUVmax of 2.8 ±
3.3 post IV diazepam (p < 0.0001). Approximately 89% (24 of 27) of scans had no significant residual BAT activity. The three
remaining scans had a reduction in SUVmax ranging from 23-64% following diazepam administration. No adverse effects were
noted. Conclusion: We observed a significant reduction in brown fat activity in para-spinal, cervical, mediastinal, para-adrenal, and
supra- and infra-clavicular regions on PET/CT following premedication with intravenous diazepam. We feel that IV benzodiazepines
should be considered a pharmacologic option for reducing BAT FDG uptake, which in turn, will aid in distinguishing physiologic
metabolic activity from pathology. (ajnmmi1105002).
Keywords: Brown adipose tissue, diazepam, 18F-FDG PET
Full text PDF
Address all correspondence to:
Dr. Rajan Rakheja Royal
Victoria Hospital
687 Pine Avenue
Montreal, Quebec, Canada, H3A 1A1.
Tel: 514-295-6104
E-mail: rajan.rakheja@gmail.com
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