FDG Uptake in Brown Adipose Tissue Mimicking an Adrenal Metastasis: Source of False-Positive Interpretation

Reddy, Madhusudhan P.; Ramaswamy, Mohan

doi:10.1097/01.rlu.0000156798.59230.2e

Cited by 13 publications

(8 citation statements)

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“…There are some indications that brown adipose tissue activity is blocked by diazepam or other tranquilizers (6,60), and such treatment is recommended for "nervous" patients (35) [but not all find such effects (21), at least not experimental animals]. The nuclear medicine literature refers to previously observed diazepam-binding sites in brown adipose tissue as an explanation for this effect, but because brown adipose tissue is stimulated by the sympathetic nervous system and because anxiety may activate this system, it is possible that the inhibition of brown fat FDG uptake by diazepam is due to reduced sympathetic activity.…”

Section: Human Brown Adipose Tissue Activity Is Sympathetically Stimumentioning

confidence: 99%

Unexpected evidence for active brown adipose tissue in adult humans

Nedergaard

Bengtsson²,

Cannon³

2007

American Journal of Physiology-Endocrinology and Metabolism

1,557

1,179

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The contention that brown adipose tissue is absent in adult man has meant that processes attributed to active brown adipose tissue in experimental animals (mainly rodents), i.e., classical nonshivering thermogenesis, adaptive adrenergic thermogenesis, diet-induced thermogenesis, and antiobesity, should be either absent or attributed to alternative (unknown) mechanisms in man. However, serendipidously, as a consequence of the use of fluorodeoxyglucose positron emission tomography (FDG PET) to trace tumor metastasis, observations that may change that notion have recently been made. These tomography scans have visualized symmetrical areas of increased tracer uptake in the upper parts of the human body; these areas of uptake correspond to brown adipose tissue. We examine here the published observations from a viewpoint of human physiology. The human depots are somewhat differently located from those in rodents, the main depots being found in the supraclavicular and the neck regions with some additional paravertebral, mediastinal, para-aortic, and suprarenal localizations (but no interscapular). Brown adipose tissue activity in man is acutely cold induced and is stimulated via the sympathetic nervous system. The prevalence of active brown adipose tissue in normal adult man can be only indirectly estimated, but it would seem that the prevalence of active brown adipose tissue in the population may be at least in the range of some tens of percent. We conclude that a substantial fraction of adult humans possess active brown adipose tissue that thus has the potential to be of metabolic significance for normal human physiology as well as to become pharmaceutically activated in efforts to combat obesity.

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Section: Human Brown Adipose Tissue Activity Is Sympathetically Stimumentioning

confidence: 99%

Unexpected evidence for active brown adipose tissue in adult humans

Nedergaard

Bengtsson²,

Cannon³

2007

American Journal of Physiology-Endocrinology and Metabolism

1,557

1,179

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“…A high glucose uptake of active BAT allows its detection in human patients undergoing 18 F-FDG PET/CT imaging and may at the same time interfere with diagnostic tumor detection (6,9,10,12).…”

Section: Discussionmentioning

confidence: 99%

“…In 2009, 3 independent studies finally reported the unequivocal interpretation of said signals as metabolically active BAT (3)(4)(5). In clinical practice, activated BAT disturbs diagnosis (6). Particularly in the context of tumor diagnosis, this is a not-tobe-underestimated problem (7)(8)(9)(10).…”

mentioning

confidence: 99%

Active Brown Fat During ¹⁸F-FDG PET/CT Imaging Defines a Patient Group with Characteristic Traits and an Increased Probability of Brown Fat Redetection

et al. 2017

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Brown adipose tissue (BAT) provides a means of nonshivering thermogenesis. In humans, active BAT can be visualized by 18 F-FDG uptake as detected by PET combined with CT. The retrospective analysis of clinical scans is a valuable source to identify anthropometric parameters that influence BAT mass and activity and thus the potential efficacy of envisioned drugs targeting this tissue to treat metabolic disease. Methods: We analyzed 2,854 18 F-FDG PET/CT scans from 1,644 patients and identified 98 scans from 81 patients with active BAT. We quantified the volume of active BAT depots (mean values in mL 6 SD: total BAT, 162 6 183 [n 5 98]; cervical, 40 6 37 [n 5 53]; supraclavicular, 66 6 68 [n 5 71]; paravertebral, 51 6 53 [n 5 69]; mediastinal, 43 6 40 [n 5 51]; subphrenic, 21 6 21 [n 5 29]). Because only active BAT is detectable by 18 F-FDG uptake, these numbers underestimate the total amount of BAT. Considering only 32 scans of the highest activity as categorized by a visual scoring strategy, we determined a mean total BAT volume of 308 6 208 mL. In 30 BAT-positive patients with 3 or more repeated scans, we calculated a much higher mean probability to redetect active BAT (52% 6 25%) as compared with the overall prevalence of 4.9%. We calculated a BAT activity index (BFI) based on volume and intensity of individual BAT depots. Results: We detected higher total BFI in younger patients (P 5 0.009), whereas sex, body mass index, height, mass, outdoor temperature, and blood parameters did not affect total or depotspecific BAT activity. Surprisingly, renal creatinine clearance as estimated from mass, age, and plasma creatinine was a significant predictor of BFI on the total (P 5 0.005) as well as on the level of several individual depots. In summary, we detected a high amount of more than 300 mL of BAT tissue. Conclusion: BAT-positive patients represent a group with a higher than usual probability to activate BAT during a scan. Estimated renal creatinine clearance correlated with the extent of activated BAT in a given scan. These data imply an efficacy of drugs targeting BAT to treat metabolic disease that is at the same time higher and subject to a larger individual variation than previously assumed.

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“…Secondly, brown fat FDG uptake in the adrenal region can mimic adrenal uptake and was previously described (14,15). However, review of the FDG PET/CT scans was not hampered by brown fat.…”

Section: Discussionmentioning

confidence: 99%

Fluorodesoxyglucose uptake in the remaining adrenal glands during the follow-up of patients with adrenocortical carcinoma: do not consider it as malignancy

Leboulleux¹,

Deandreis²,

Escourrou³

et al. 2011

European Journal of Endocrinology

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Objective: To make the specificity of fluorodesoxyglucose ( 18 FDG) positron emission tomography (PET) precise, in the follow-up of patients with adrenal cancer. Design: This single centre retrospective study assessed the frequency and outcome of 18 FDG uptake in the remaining adrenal glands after adrenalectomy for adrenocortical carcinoma (ACC) or malignant phaeochromocytoma (PH). Results: Two hundred and ten 18 FDG PET scans in 62 ACC patients, all under 1,ortho-1,para 18 FDG PET scans, in 10 (16%) ACC patients and in none of the PH patients.18 FDG uptake was found in 4% of the patients before the onset of o,p 0 -DDD, in 29% of the patients 0-6 months after the onset of o,p 0 -DDD (PZ0.05), in 26% of the patients 6-12 months (PZ0.072) after the onset of o,p 0 -DDD and in 14% of the patients 12-24 months after the onset of o,p 0 -DDD. It was never found later than 24 months after the onset of o,p 0 -DDD. Adrenal glands with 18 FDG uptake were normal on computed tomography scans with i.v. contrast agent in all cases.18 FDG uptake in the remaining adrenal glands decreased and disappeared on subsequent FDG PET imaging in eight of the patients with follow-up available. Conclusions:18 FDG uptake in the remaining adrenal glands occurred in 14-29% of the patients followed for ACC within 24 months after adrenalectomy and onset of o,p 0 -DDD. This uptake is transient and should not be considered as suspicious for malignancy.European Journal of Endocrinology 164 89-94

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FDG Uptake in Brown Adipose Tissue Mimicking an Adrenal Metastasis: Source of False-Positive Interpretation

Cited by 13 publications

References 1 publication

Unexpected evidence for active brown adipose tissue in adult humans

Unexpected evidence for active brown adipose tissue in adult humans

Active Brown Fat During ¹⁸F-FDG PET/CT Imaging Defines a Patient Group with Characteristic Traits and an Increased Probability of Brown Fat Redetection

Fluorodesoxyglucose uptake in the remaining adrenal glands during the follow-up of patients with adrenocortical carcinoma: do not consider it as malignancy

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FDG Uptake in Brown Adipose Tissue Mimicking an Adrenal Metastasis: Source of False-Positive Interpretation

Cited by 13 publications

References 1 publication

Unexpected evidence for active brown adipose tissue in adult humans

Unexpected evidence for active brown adipose tissue in adult humans

Active Brown Fat During 18F-FDG PET/CT Imaging Defines a Patient Group with Characteristic Traits and an Increased Probability of Brown Fat Redetection

Fluorodesoxyglucose uptake in the remaining adrenal glands during the follow-up of patients with adrenocortical carcinoma: do not consider it as malignancy

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Active Brown Fat During ¹⁸F-FDG PET/CT Imaging Defines a Patient Group with Characteristic Traits and an Increased Probability of Brown Fat Redetection