Anatomy
There are five segments in the stomach: the cardia, fundus, body, antrum, and pylorus.
- Cardia: Surrounds esophageal orifice into stomach. It is characterized on barium studies by three or four stellate folds that radiate to a central point at the gastroesophageal junction, also known as the cardiac “rosette”1.
- Fundus: Most cephalic part of stomach, located superiorly and to left relative to cardia, touching left hemidiaphragm.
- Body: Defined as the portion of the stomach extending from the gastric cardia to the smooth bend in the mid lesser curvature known as the incisura angularis.
- Antrum: Defined as the portion of the stomach extending from the incisura angularis to the pylorus.
- Pylorus: Sphincter opening into duodenum, formed by thickened middle layer of smooth muscle and thin, fibrous septum.
Fig. 1: Normal anatomy of stomach on double-contrast barium study.
Fig. 2: Double-contrast barium study in right anterior oblique position shows normal gastric cardia with smooth folds radiating to central point (white arrow), also known as cardiac rosette.
Principles of Image Analysis
- Appearance of the Stomach: Examines the overall position, shape, and size of the stomach.
- Luminal Contour:
- In the barium pool, the contour is demarcated by a smooth edge of barium.
- With air contrast, the luminal contour appears as a smooth, continuous barium-coated white line.
- On the dependent wall, protruded lesions usually appear as radiolucent2.
- On the nondependent wall, protruded lesions appear as barium coated “ring shadows” due to barium coating the edge of these lesions2.
- When filled with barium, depressed lesions appear as barium collections on the dependent wall2.
- When barium spills out of depressed lesions on the dependent wall, they may appear as ring shadows2.
Pattern Approach for Double-Contrast Diagnosis
Protruded lesions
- Polyps: Polyps are small protrusions from the mucosal surface, either sessile or pedunculated3. Based on pathology, polyps can be classified as Fig. 3:
Fig. 3: Calcification of gastric polyps
Fig. 4: Double-contrast barium study in supine position shows multiple hyperplastic polyps. Polyps on dependent wall of gastric antrum as small, round or ovoid, finely lobulated radiolucent filling defects in barium pool (arrowheads). In contrast, polyps on nondependent wall are coated by barium and appear as white lines (arrows).
- Masses: For gastric masses larger than 2 cm in size, barium studies are extremely helpful for determining whether the lesions arise from the mucosa or non-mucosa.
Fig. 5: Mucosal and non-mucosal masses on double-contrast barium study
Fig. 6: A. Double contrast barium study in right lateral position showing a well-defined sharply marginated submucosal lesion in the gastric cardia(white arrowhead).
B. Coronal reformat CT of the same patient shows the submucosal mass in gastric cardia(white arrow). Final pathology confirmed the diagnosis of GIST.
Fig. 7: Double-contrast barium study in left posterior oblique position shows “bull's eye sign” or “target sign” of the lesion (white arrow) at gastric antrum which is seen as linear collections of barium surrounded by radiolucent mounds of edema. The differential diagnosis of this image feature on double-contrast barium study could be aphthoid ulcers, mucosal or submucosal tumor with central ulceration, haematogenous gastric metastases.
- Conglomerate mass of gastric varices: A smooth, undulating submucosal lesion on the medial aspect of the fundus near the gastric cardia4.
- Hypertrophied antral-pyloric fold: Submucosal defect extending from the lesser curvature of the distal antrum to the pylorus5.
Depressed lesions
- Erosions: An erosion is a focal area of mucosal necrosis confined to the epithelium or lamina propria without extending through the muscularis mucosae into the submucosa. Image features of erosions on double contrast studies:
- 1–2 mm in depth collections of barium, usually in the gastric antrum1.
- May be punctate, round, linear, or stellate in configuration and are often surrounded by radiolucent halos of edematous mucosa1.
Fig. 9: Double-contrast barium study in supine position shows erosions at gastric lower body because of previous caustic ingestion corrosive. Erosions are seen as punctate (white arrow) collections of barium surrounded by radiolucent mounds of edema (black arrows).
- Ulcers: An ulcer is a focal area of mucosal disruption that penetrates through the muscularis mucosae into the deeper layers of the gastric wall. There are some image features on double-contrast examination for differentiating benign and malignant ulcers.
Fig. 8: Benign and malignant ulcers on double-contrast barium study
Fig. 10: Double-contrast barium study in supine position shows benign gastric ulcer at lesser curve(arrow) with uniform fold convergence on the ulcer.
Fig. 11: Double-contrast barium study in left posteior oblique position shows malignant gastric ulcer due to advanced carcinoma in gastric cardia. There is a central pooling of barium in the gastric ulcer(white arrow) surrounded by fused and clubbed mucosal folds.
- Diverticula: Diverticula are uncommon in the stomach. The majority arise from the posterior wall of the gastric fundus. Diverticula can be distinguished from ulcers by their smooth contour, broad or shallow necks, and lack of folds radiating to their margins8.
Fig. 12: A. Double-contrast barium study in left posterior oblique position shows a diverticulum filled with barium at gastric fundus(black arrow).
B. (The same patient) Residual barium in the gastric diverticulum after barium spilled out(white arrow).
Gastric narrowing
Narrowing of the luminal contour of the stomach may be caused by scarring, infiltrating tumor, or extrinsic diseases secondarily affecting the stomach1.
- Scarring from peptic ulcer disease: Asymmetric retraction of one wall of the stomach with smooth, straight folds that radiate to the site of the healed ulcer, tapered narrowing of the gastric antrum or weblike antral narrowing9.
- Scarring from ingestion of NSAIDs: Flattening of the greater curvature of the distal antrum9.
- Severe scarring from previous caustic ingestion: Diffuse antral narrowing indistinguishable from antral carcinoma on barium studies10.
- Infiltrating or advanced gastric carcinoma or metastatic breast cancer: Long-segment narrowing of the stomach or diffuse narrowing of the stomach1.
- Linitis plastica appearance: The narrowed lumen is rigid and non-distensible at fluoroscopy, and gastric peristalsis is obliterated11.
Fig. 13: A. Double contrast barium study in left posterior oblique position shows irregular contour and segmental narrowing of the gastric antrum and pylorus(black arrows).
B. The contrast-enhanced CT of the same patient shows irregular gastric wall thickening at antrum and pylorus with increased enhancement(white arrows). The pathology proved the final diagnosis as gastric carcinoma.
Fig. 14: Double contrast barium study in supine position of the patient with diffusely infiltrate adenocarcinoma shows “Linitis plastica appearance” of stomach. Linitis plastica appearance is usually due to gastric carcinoma, metastases to stomach(especially breast cancer) and caustic gastric injury.
- Crohn disease, granulomatous diseases such as sarcoidosis, syphilis, and tuberculosis: Tapered narrowing of the gastric antrum12.
- Long-standing gastrojejunal anastomosis without an antrectomy: Antral narrowing results from gastric atrophy1.