Gastric volvulus

Types of gastric rotation

Depending on the axis around which the torsion occurs, there are two main types of volvulus:

• Organoaxial volvulus (organoaxial rotation). Torsion occurs around the longitudinal axis of the organ. Barium studies or CT scans show that the stomach is "vertically flipped" — its greater curvature lies above the lesser curvature.
• Mesenteroaxial volvulus (mesenteroaxial rotation). Rotation occurs around a transverse axis perpendicular to the longitudinal axis (along the attachment line of the lesser and greater omentum). Imaging shows a "flipped stomach" (horizontally): the distal part (antrum and pylorus) is displaced cranially relative to the fundus and proximal portion. This type is frequently associated with diaphragmatic injuries.

Imaging findings of volvulus

Both conventional radiography and computed tomography are used to detect this pathology.

• The supine plain radiograph shows a gas-filled, markedly dilated, spherical stomach.
• In the upright position, a fluid-gas level is detected in the projection of the stomach, which may be displaced into the mediastinum or upper abdomen.
• Computed tomography and barium fluoroscopy allow precise determination of the rotation type and visualization of the twist site as the direct cause of obstruction.

Special attention should be paid to signs of perforation: in wall gangrene, linear gas within the wall or free gas in the peritoneal cavity may appear (allowing visualization of both sides of the gastric wall).

Differential diagnosis of bowel dilation

Obstructive symptoms in volvulus sometimes require differentiation from small bowel obstruction (SBO) and large bowel obstruction.

Causes of SBO can include adhesions, hernias, intussusception, or intraluminal masses (gallstones in gallstone ileus). An important SBO sign on radiographs is the "string of pearls" sign — a line of gas bubbles trapped between circular folds in a fluid-filled bowel.

Gastric pneumatosis: differential series

When gas is detected within the gastric wall (pneumatosis), it is important to distinguish between infectious and non-infectious processes:

1. Gastric emphysema (gastric emphysema). Non-infectious gas accumulation (curvilinear lucencies along the contour of the wall). Can occur in ulcers, COPD, trauma, ischemia, or after ingestion of caustic substances.
2. Emphysematous gastritis. Acute infectious condition caused by gas-forming flora (e.g., E. coli, Clostridium welchii).
3. Phlegmonous gastritis. Panmural inflammation caused by non-gas-forming microbes (streptococci, staphylococci).

Infectious forms are rare, but always follow a fulminant course and are accompanied by severe complications.

Class and exam questions

What else to study on this topic

• Mechanical vs. paralytic ileus
• Gallstone ileus
• Intramural, intraluminal, and extraluminal causes of SBO
• Emphysematous and phlegmonous gastritis: pathogenesis

Other topics in the section "Diagnostic Radiology of the Abdominal Organs"

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