Repeatability of brown adipose tissue measurements on FDG PET/CT following a simple cooling procedure for BAT activation

PLoS One. 2019 Apr 17;14(4):e0214765. doi: 10.1371/journal.pone.0214765. eCollection 2019.

Abstract

Brown Adipose Tissue (BAT) is present in a significant number of adult humans and can be activated by exposure to cold. Measurement of active BAT presence, activity, and volume are desirable for determining the efficacy of potential treatments intended to activate BAT. The repeatability of 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET) measurements of BAT presence, activity, and volume under controlled conditions has not been extensively studied. Eleven female volunteers underwent double baseline FDG PET imaging performed following a simple, regional cold intervention intended to activate brown fat. The cold intervention involved the lightly-clothed participants intermittently placing their feet on a block of ice while sitting in a cooled room. A repeat study was performed under the same conditions within a target of two weeks. FDG scans were obtained and maximum standardized uptake value adjusted for lean body mass (SULmax), CT Hounsfield units (HU), BAT metabolic volume (BMV), and total BAT glycolysis (TBG) were determined according to the Brown Adipose Reporting Criteria in Imaging STudies (BARCIST) 1.0. A Lin's concordance correlation (CCC) of 0.80 was found for BMV between test and retest imaging. Intersession BAT SULmax was significantly correlated (r = 0.54; p < 0.05). The session #1 mean SULmax of 4.92 ± 4.49 g/mL was not significantly different from that of session #2 with a mean SULmax of 7.19 ± 7.34 g/mL (p = 0.16). BAT SULmax was highly correlated with BMV in test and retest studies (r ≥ 0.96, p < 0.001). Using a simplified ice-block cooling method, BAT was activated in the majority (9/11) of a group of young, lean female participants. Quantitative assessments of BAT SUL and BMV were not substantially different between test and retest imaging, but individual BMV could vary considerably. Intrasession BMV and SULmax were strongly correlated. The variability in estimates of BAT activity and volume on test-retest with FDG should inform sample size choice in studies quantifying BAT physiology and support the dynamic metabolic characteristics of this tissue. A more sophisticated cooling method potentially may reduce variations in test-retest BAT studies.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adipose Tissue, Brown / diagnostic imaging*
  • Adipose Tissue, Brown / metabolism*
  • Adolescent
  • Adult
  • Cold Temperature
  • Female
  • Fluorodeoxyglucose F18
  • Glucose / metabolism
  • Glycolysis
  • Healthy Volunteers
  • Humans
  • Positron Emission Tomography Computed Tomography
  • Prospective Studies
  • Radiopharmaceuticals
  • Reproducibility of Results
  • Young Adult

Substances

  • Radiopharmaceuticals
  • Fluorodeoxyglucose F18
  • Glucose

Grants and funding

This project was sponsored by the National Institute of Diabetes and Digestive and Kidney Diseases (IR210K090799) and was conducted at Johns Hopkins University. The NIH provided a grant to MMTC. MMTC provided a subcontract to JHU. Daniel D. Mawhinney and Fred Sterzer, are employees at MMTC Inc., which provided funding for the study. MMTC Inc. provided support in the form of salaries for authors (DDM and FS), but did not have any additional role in the study design, data collection and analysis, decision to publish, or preparation of the manuscript. The specific roles of these authors are articulated in the 'author contributions' section.