PET/MRI of glucose metabolic rate, lipid content and perfusion in human brown adipose tissue

Figures

• 

  Figure 1. Schematic overview of the study protocols. (A) Cooling-reheating protocol and (B) Control protocol. Timings of procedures are indicated. Other procedures denote measures not included in the present work. H2O denotes [15O]water and FDG denotes [18F]FDG.

• 

  Figure 2. Example of an axial FF map (greyscale) overlaid with the corresponding MRglu map (heat colour scale) and segmentations representing sBATHI (blue contour) and sBATLO (green contour).

• 

  Figure 3. Correlation between MRglu and FF in sBAT and sBATHI at (A) baseline and (B) the end of ~ 3 h of cold exposure (cold scan 1). ρ, Spearman rank-order correlation coefficient.

• 

  Figure 4. Changes in FF, perfusion and VA, within sBAT and SAT, with respect to baseline. (A) Changes in FF during the Cooling-reheating and Control protocols, with significance bars indicating changes during the Cooling-reheating protocol (at the bottom) and differences between the two protocols (at the top). (B) Changes in perfusion and VA during the Cooling-reheating protocol indicated with significance bars. Measurements represent group mean values based on complete data available for estimating the changes between individual time points, i.e. different group mean values can be based on a different number of subjects. Solid line, Cooling-reheating protocol. Dotted line, Control protocol. Time, approximate mean session time for all subjects. pp, percentage points. Changes evaluated using Wilcoxon signed-rank test. Change between time points at **P < 0.01, *P < 0.05. Trend of change between time points at †0.05 ≤ P < 0.10. ns, non-significant.

• 

  Figure 5. Changes in (A) FF, (B) perfusion and (C) VA within sBAT of individual subjects over time during the Cooling-reheating protocol. Solid lines, sBAT. Dashed lines, sBATHI. Yellow, red and brown correspond to the four subjects with the highest, intermediate and lowest sBAT-MRglu, respectively. In the sBAT-FF measurement, cold scan 1 was missing for one subject and cold scan 2 for two other subjects. A fourth subject did not show any sBATHI. In the sBAT-VA measurement, the baseline scan was missing for one subject and the reheated scan for another subject. Time, approximate mean session time for all subjects.

• 

  Figure 6. Correlation between cold-induced MRglu and changes in FF. sBAT-MRglu vs. the change in sBAT-FF between baseline and (A) ~ 3 h of cold exposure (cold scan 1) and (B) ~ 4.5 h of cold exposure (cold scan 2). ρ, Spearman rank-order correlation coefficient.