Virtual Three-dimensional Computed Tomography Assessment of the Gastric Pouch Following Laparoscopic Roux-Y Gastric Bypass

Background The construction of the gastric pouch during surgery is largely based on the prevailing dogma of Roux-Y gastric bypass (RYGB) surgery. The scarce data that exist suggest that the smaller the gastric pouch, the greater the weight loss after surgery. Current estimations of pouch volume have inherent limitations. We describe the use of virtual three-dimensional computed tomography (3D CT) to assess pouch volume in the immediate postoperative period. Methods We performed 3D CT on three patients 1 day after laparoscopic RYGB using a 16-channel multidetector CT scan. Effervescent granules were administered, along with 1 oz of water, orally to achieve gastric pouch distension. Transaxial images were transferred to the 3D workstation (Vitrea, Vital Images, Inc.) and endoluminal views of the gastric pouch were generated with perspective volume rendering. Pouch area was also measured from the standard postoperative upper gastrointestinal (UGI) contrast study. Results All three patients were female, with a mean preoperative body mass index (BMI) of 43.7 kg/m² and a mean age of 44.3 years. Mean pouch height was 4.07 cm, mean pouch width was 3.79 cm, and mean pouch depth was 2.1 cm. The mean calculated pouch volume was 31.6 cm³. The calculated pouch area using 3D CT was statistically indistinct from the pouch area calculated using the UGI study (15.2 cm² vs 16.9 cm²; p = 0.549.) Conclusion For the first time, we describe the use of 3D CT to accurately measure postoperative pouch volume. In addition, we were able to confirm the utility of area (postoperative UGI) as an accurate surrogate for pouch volume.