Estimating the cold-induced brown adipose tissue glucose uptake rate measured by 18F-FDG PET using infrared thermography and water-fat separated MRI

Figure 1. Schematic overview of the study protocol. Abbreviations used: MRI: magnetic resonance imaging, IRT: infrared thermography, PET: positron emission tomography.

Figure 2. Coronal slice showing multiple BAT depots. MRI-derived fat signal image from the dual-echo scan in grayscale with the PET-derived GUR superimposed using the heat colourmap. The green lines delineate the areas over which the total BAT GUR was summed.

Figure 3. IRT image of a subject with hands and feet in cold water. Red lines delineate the SCF, black boxes delineate the PNR.

Figure 4. Axial slice showing the supraclavicular BAT depot. MRI-derived FF map from the multi-echo scan using the grayscale colourmap with the PET-derived GUR superimposed using the heat colourmap. The green delineation is the initial rough delineation and the blue delineation the area remaining after thresholding and erosion that was used to calculate BAT FF15e and R2*. Note that data collected during the cooling is shown to illustrate the overlap between areas with a high GUR and the areas segmented to calculate BAT FF15e and R2*.

Figure 5. Simple linear regression plots with total BAT GUR as the dependent variable and (a) the SCFcold temperature as the independent variable, or (b) the BAT FF15e as the independent variable. Blue crosses represent observations, the solid red lines the fitted regressions, and the dotted red lines the 95% confidence bounds.

Figure 6. Axial slice showing the bilaterally symmetric FDG uptake in the posterior subcutaneous adipose tissue. MRI-derived fat signal image from the dual-echo scan in grayscale with the PET-derived GUR superimposed using the heat colourmap. The blue lines delineate the posterior subcutaneous adipose tissue areas with a GUR > 10 μmol/100 ml/min. The green lines delineate the remaining BAT areas with a GUR > 10 μmol/100 ml/min.