Swallow Magnetic Resonance Imaging Compared to 3D-Computed Tomography for Pouch Assessment and Hiatal Hernias After Roux-en-Y Gastric Bypass

Abstract

Introduction/purpose: Weight regain and weight loss failure after bariatric surgery are important issues that may require a weight regain procedure. Three-dimensional-computed tomography (3D-CT) is a well-established method allowing exact measurements of pouch volume. The aims of this study were to prove the applicability of swallow MRI as a non-ionizing procedure and compare it to 3D-CT in patients after weight regain procedures following RYGB.

Materials and methods: Twelve post-RYGB patients who had a follow-up operation for weight regain before 12/2017 were included in this prospective study. Swallow MRI and 3D-CT were performed in each patient to evaluate the size of the anastomosis, pouch volume, and intrathoracic pouch migration (ITM).

Results: Mean pouch volume in swallow MRI and 3D-CT were 40.4 ± 21.0 ml and 43.5 ± 30.2 ml, respectively (p = 0.83), and pouch diameter at the maximal distention was 35.3 ± 5.9 ml (MRI) and 31.0 ± 10.0 ml (CT) (p = 0.16). The rate of ITM was 75% in both examinations (p = 1.0).

Conclusion: Swallow MRI is a valid method for the assessment of pouch volume in different phases of the swallowing process and is comparable to 3D-CT. The diagnosis of ITM using swallow MRI was equal to 3D-CT.

Keywords: 3D-volumetry; Roux-en-Y gastric bypass; Swallow MRI; Weight regain.

Fig. 1

A 30-year-old female who underwent RYGB, pouch resizing, and banding; parasagittal dynamic bFFE MRI (a) and reconstructed 3D-CT (b) demonstrate the distended pouch. There is mild ITM

Fig. 2

A 50-year-old female who underwent RYGB, pouch resizing, and banding (a short, bold arrow); dynamic MRI shows filling of the pouch during fluid intake (a long arrows). Moderate ITM was suspected and confirmed by CT (b short arrow indicates staple lines above the diaphragm)