Oral Presentation Annual Meetings of the Endocrine Society of Australia and Society for Reproductive Biology and Australia and New Zealand Bone and Mineral Society 2016

The value of infrared thermography in the detection of brown adipose tissue activity in humans (#81)

Veronique Chachay 1 2 , Moe Thuzar 1 3 , Phillip Law 1 4 , Ken Ho 1 3
  1. School of Medicine , The University of Queensland, Brisbane, Queensland
  2. School of Human Movement and Nutrition Sciences, The University of Queensland, St Lucia, QLD, Australia
  3. Department of Endocrinology, The Princess Alexandra Hospital, Brisbane, Queensland, Australia
  4. Department of Medical Imaging, The Princess Alexandra Hospital, Brisbane, Queensland

Background
PET-CT is the standard method for detecting brown adipose tissue (BAT) in humans. Alternatives are required because of the radiation and cost of PET-CT imaging. We reported in a pilot study of 29 scans that infrared thermography (IRT) showed promise as a tool for detecting BAT1.

Aim
To evaluate the value of IRT in detecting BAT status and changes in BAT activity.

Method
Eighty-four PET-CT scans were evaluated after 3hr of cooling at 19°C, in parallel with skin temperature measurements overlying the supraclavicular (SCL) fossa and the lateral mediastinum (control). BAT-positivity was defined by SUV≥2 on PET-CT. A subgroup of 12 subjects participated in a placebo-controlled study of the effect of glucocorticoids on BAT.

Results
Forty out of the 84 scans were BAT positive. Compared to the BAT-negative group, left SCL temperature was higher in the BAT-positive group before (32.8 vs 33.3°C; p=0.03) and throughout cooling (p<0.001). The control temperature or temperature difference (Δtemp) between left SCL and control area did not differ significantly between the groups. Left SCL and control temperatures fell significantly (p<0.001) with left SCL temperature being higher (p=0.003) than control temperature throughout cooling. On ROC analysis, the left SCL temperature or ∆temp conferred a sensitivity of 20% at a specificity of 90% for BAT detection. The findings were similar on the right. Glucocorticoids reduced BAT activity significantly (SUVmax 6.1±2.2 to 3.7±1.2,
p<0.05). Left SCL temperature fell by a significantly greater degree (p<0.05) during glucocorticoid treatment after cooling (-0.3±0.1 vs -0.7±0.10C).

Summary
SCL temperatures are higher in BAT-positive than BAT-negative subjects but poorly discriminate between BAT-positive and -negative subjects. Within subjects, a fall in BAT activity is accompanied by a fall in SCL temperatures.

Conclusion: IRT is an unreliable tool for detecting BAT. It may have a role for monitoring changes in BAT activity within individuals.

  1. 1 Jang et al. Physiol Rep, 2(11), e12167, 2014