Fig 1.
Differences between the two cohorts.
a) Sex difference: Stacked bar plot depicting the top 15% percent of the overall population, showing the higher incidence (OR = 3.62) of positive BAT in females compared to males. b) Age and c) BMI difference of the BAT-positive cohort. Density plots showing the shift of age and BMI from the overall population to the BAT-positive cohort (blue), who were found to be significantly younger and lighter.
Table 1.
Cohort details.
Fig 2.
a) Schematic drawing of the different depots, some of which were summarized as indicated by the coloration into the three categories c) supraclavicular d) mediastinal and e) infradiaphragmatic. b) Showing the total number of BAT-positive subjects grouped by the most caudally active depot of either supraclavicular (including axillary and nuchal), mediastinal or infadiaphragmal BAT. c-e) Coronal MIP PET images (left) and fused PET/CT slices (right) of representative subjects in the according category. All pictures also show variable glucose uptake of the liver, intestines and myocardium as well as strong emissions from the renal pelvis, the latter being concentrated 18FDG breakdown products excreted through the urine. This can be appreciated in the fused d) image, where the true BAT activity is located in a fat depot on the patient’s left side (right side on the picture) adjacent to the first lumbar vertebra.
Fig 3.
Quantification of glycolysis in the different depots.
A clear increase of all three metabolic PET-parameters MFV, TFG and SUVmax, from the supraclavicular depots to the more caudally located infradiaphragmatic depots can be appreciated.
Fig 4.
Differences in BAT activation between individuals and categories.
The first column depicts the total fat glycolysis (TFG) in relation to BMI (a), age (b) and external temperature (c). As can be guessed by the visual impression of the scatter plots, no clear correlation between either of the factors and the TFG could be established. In the second column however, the same data is shown and instead of using the metabolic activity, it is simply ordered by the morphological type of activation, showing clearly more activated depots with lower BMI, age and temperature. The dashed lines in (a) and (b) represent the significant linear correlation (p > 0.05), the asterisk (*) in (c) marks the only statistically significant difference (p<0.0125) in absence of a linear correlation.
Table 2.
Morphological differences in BAT activity.