Los Angeles -- A novel PET imaging framework reveals
that bariatric surgery impacts not only body weight, but also the metabolic
function of multiple organs. These PET‑derived insights into organ-level responses
to surgery could support more precise treatment monitoring and personalized
metabolic care. This research was presented at the Society of Nuclear Medicine
and Molecular Imaging 2026 Annual Meeting.
For more than 70 years, bariatric
surgery has been used to induce durable weight loss and improve obesity-related
comorbidities. While the increase in GLP-1 medications has reduced the number
of individuals who seek this surgery, tens of thousands of Americans each year
still opt to undergo bariatric surgery to avoid lifelong medication dependency.
For these patients, the recovery period is critical to ensure proper healing
and prevent complications.
"Currently, clinicians do not have a clear way to see how
the body's metabolism changes after bariatric surgery," said Zeyang Wang, MSc, PhD candidate in the Division of Nuclear
Medicine, Department of Biomedical Imaging and Image-Guided Therapy at Medical
University of Vienna in Austria. "Having a comprehensive understanding about
the changes that are happening across multiple organs would provide valuable
data to clinicians as they provide follow-up care."
The retrospective study included 32 patients with obesity
undergoing laparoscopic sleeve gastrectomy or one-anastomosis gastric bypass who
underwent whole-body 18F-FDG PET/CT and comprehensive laboratory assessments both
before surgery and one year after surgery. 18F-FDG uptake was measured in subcutaneous
and visceral adipose tissue, liver, pancreas, spleen, adrenal glands, and
skeletal muscle to determine metabolic changes. Results were compared between
the pre- and post-surgery scans and with those of healthy controls, and
associations among organ-level metabolic changes were evaluated.
Surgery was found to induce coordinated metabolic changes
across multiple organs, including fat, liver, pancreas, muscle, cardiovascular
structures, bone-related tissues, and immune-endocrine organs. Changes in organ
metabolism and volume correlated with improvements in glycemic, lipid,
endocrine, and inflammatory markers. Network analysis showed stronger
connections between organs, indicating that metabolic processes across the body
became more synchronized after surgery.
"For patients, these findings suggest that metabolic
recovery after bariatric surgery is a whole-body process," said Wang. "Molecular imaging may help show how different organs respond after surgery,
beyond what can be measured by weight loss or blood tests alone. This work
supports the use of whole-body PET/CT as a tool to map organ-level metabolic
health."