Bariatric surgery and radiologists: besides complications, an important role in the evaluation of treatment efficacy and effects.

Purpose: Bariatric surgery is the most effective way of controlling severe obesity and its medical comorbidities. Our aim was to investigate the impact of bariatric treatment on body composition (BC) and bone metabolism over a period of 24 months following the surgical intervention and to determine the role of dual energy x-ray absorptiometry (DXA) in the management of obesity. Methods and Materials: We prospectively enrolled 22 female patients (46.5±8.0 year-old;42.7±7.1Kg/m2) directed to bariatric surgery (Roux-en-Y gastric bypass on vertical banded gastroplasty). All patients underwent whole body and lumbar spine DXA scans before treatment and after 3-6-12 and 24 months. BC parameters were assessed (fat mass-FM; non-bone lean mass-LM; bone mineral content, and density-BMD) on whole body and regional-basis. Thus, differential rates of mass and BMD changes were calculated to define the trend in the overall weight loss. Results: Body mass index decreased in the first 12 months and grew steady between 12 and 24 months (p < 0.05). A decrease of FM/LM ratio was observed in both total and android region at 12 months (FM↓↓LM↓), while slightly increased between 12 and 24 months (FM↑LM↓). Similar trend was observed for central and peripheral fat distribution ratio (Δ=-30.4%±31.0% and Δ=6.9%±13.4%, respectively; p < 0.05). A reduction of total and lumbar BMD was observed at 12 months, even stronger at 24 months compared to pre-treatment values (Δ=-3.9%±1.7% and Δ=-6.1%±3.3%, respectively; p < 0.05). Conclusion: BC and bone metabolism are significantly modified after bariatric surgery. DXA is fundamental in the investigation of patients submitted to surgical treatment for morbid obesity and in their clinical management.