Postoperative changes in body composition--comparison of bioelectrical impedance analysis and magnetic resonance imaging in bariatric patients.

Background Roux-en-Y gastric bypass (RYGB) result in a marked reduction of body fat and also visceral fat (VF) decrease up to 36 % in 16 weeks. This leads to positive effects on cardiometabolic risks, which are known to be correlated with the occurrence of VF. This study analyzed the validity of bioelectrical impedance analysis (BIA) for determining VF in the postoperative course. In addition, magnetic resonance imaging (MRI) was performed for prediction of whole VF in bariatric patients on the basis of a single slice.