Retrospective, multicenter, observational study of GV cases in seven hospitals. Inclusion and exclusion criteria were defined as follows; Inclusion criteria: adults over 18 years of age, GV diagnosis confirmed by CT scan by two radiologists and/or surgery, and the presence of HH prior to GV. Exclusion criteria: repeated scans performed on the same patient, non-diagnostic quality studies (artifacts or incomplete studies), discrepancies in the radiological diagnosis between two evaluators and patients without radiological evidence of HH prior to acute GV.

CT studies were performed with an axial slice thickness ranging 1 to 5 millimeters and multiplanar reconstructions. When contrast-enhanced CT scans were used, they were acquired 60 seconds after the administration of the contrast bolus, with a flow rate of 3-4 ml/s.

Sociodemographic, clinical, analytical and radiological variables related to the type of HH and GV, as well as the presence of radiological complications, were collected. It was assessed whether the GV corresponded to the typical ‘back-and-forth stomach’ image, with its pathophysiological mechanism illustrated in figure 1.

Fig 1: Pathophysiological mechanism of the ‘back-and-forth stomach’. (A) The stomach is in its normal position within the abdominal cavity. (B, C) A sliding HH occurs, progressively enlarging to include a large part or the entire stomach within the mediastinum. (D) The stomach rotates horizontally in the thoracic cavity. (E)The fundus (f) reherniates into the abdomen, leaving the antrum (a) in the thoracic cavity and triggering a GV due to the inability of gastric contents to drain. (F) The ‘Long-beak duck’ sign, in which the gastroduodenal junction is positioned above the esophagogastric junction.

Based on this theory, 4 radiological signs were defined and evaluated as independent variables. Figure 2. 

Fig 2: Radiological signs evaluated in the study cases. A) The ‘Long-beak duck’ sign, assessed in the coronal plane or in an oblique reconstruction parallel to it. B) The ‘Windswept trousers’ sign, assessed in the sagittal plane or in an oblique reconstruction parallel to it. C) The ‘Gastroesophageal uterus’ sign, assessed in the sagittal plane or in an oblique reconstruction parallel to it. D) The ‘Three circles within the hiatus’ sign, assessed in the axial plane or in an oblique reconstruction parallel to it.

Univariate descriptive analyses were performed for both quantitative and qualitative variables, as well as bivariate analyses for the dependent variable ‘presence of radiological complications’.