X hits on this document

PDF document

T h e ne w engl a nd jour na l o f medicine - page 4 / 9

24 views

0 shares

0 downloads

0 comments

4 / 9

Cold-Activated Brown Adipose Tissue in Healthy Men

A

B

C

D

E

Cold Exposure

Thermoneutral Conditions

Figure 1. Brown-Adipose-Tissue Activity as Assessed by PET–CT with 18F-FDG.

The results of PET–CT scanning in 9 of 24 subjects show variable physiologic uptake and distribution of 18F­fluorodeoxyglucose (18F­FDG) in adipose tissue (Panel A). The images in the top row are from lean subjects with the highest levels of brown­adipose­tissue activity (>500 kBq), images in the middle row are from lean subjects with median levels of activity, and images in the bottom row are from obese or overweight subjects with the lowest levels of activity (<100 kBq). The supraclavicular region has the greatest amount of brown adipose tissue. A PET scan in the transverse plane (Panel B) shows the areas of brown adipose tissue (e.g., arrow), and a CT scan (Panel C) con­ firms the areas of brown adipose tissue (arrow) according to fat density and location. Fusion of the PET and CT scans (Panel D) shows that 18F­FDG uptake is localized in fatty tissue (arrow). Comparative PET–CT scans (Panel E) reveal the patterns of 18F­FDG uptake in the same subject from the lean group after exposure to cold and under thermoneutral conditions.

Results

Twenty-three of the 24 subjects had definite, al- beit highly variable, amounts of 18F-FDG activity in the neck, supraclavicular region, chest, and ab- domen (Fig. 1A). On the fused PET–CT images, the activity was located not in muscle tissue but in fat tissue, which was therefore considered to

be brown adipose tissue (Fig. 1B through 1D). All lean subjects and 13 of the 14 overweight or obese subjects had evidence of brown-adipose- tissue activity in response to cold exposure. Mean brown-adipose-tissue activity was significantly lower in the overweight or obese subjects (102±93 kBq) than in the lean subjects (428±394 kBq) (P=0.007) (Table 2). The volume of brown adipose

n engl j med 360;15

nejm.org

april 9, 2009

1503

The New England Journal of Medicine Downloaded from nejm.org on February 3, 2015. For personal use only. No other uses without permission. Copyright © 2009 Massachusetts Medical Society. All rights reserved.

Document info
Document views24
Page views24
Page last viewedFri Oct 28 07:06:32 UTC 2016
Pages9
Paragraphs320
Words5364

Comments