Topics

Topic

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Stomach

The stomach is a muscular, hollow organ of the gastrointestinal tract that lies between the esophagus and duodenum. Located in the epigastric and left hypochondriac regions, it plays a central role in digestion, secretion, and mechanical churning of food.

It has four anatomical regions: the cardia (surrounding the gastroesophageal junction), the fundus (dome-shaped superior part), the body (largest central portion), and the pyloric region (antrum and pyloric canal leading to the pylorus). The stomach wall is composed of mucosa, submucosa, muscularis externa (three layers of smooth muscle), and serosa.

The stomach secretes gastric acid, digestive enzymes, and intrinsic factor, and initiates protein digestion with pepsin. Its muscular contractions produce churning and mixing of food to form chyme, which is then delivered in a regulated manner to the duodenum through the pyloric sphincter.

Clinically, the stomach is involved in conditions like gastritis, peptic ulcer disease, gastrointestinal bleeding, gastric carcinoma, and hiatal hernia.

Synonyms

  • Ventriculus

  • Gaster

Function

  • Receives and stores ingested food

  • Mechanically churns food and mixes it with gastric secretions

  • Initiates protein digestion and regulates emptying into the duodenum

  • Secretes intrinsic factor for vitamin B12 absorption

  • Acts as a reservoir and regulator of digestion

Nerve Supply

  • Parasympathetic: Vagus nerve (anterior and posterior gastric trunks)

  • Sympathetic: Greater splanchnic nerves via the celiac plexus

  • Enteric nervous system coordinates peristalsis and secretion

Arterial Supply

  • Left gastric artery (from celiac trunk)

  • Right gastric artery (from common hepatic artery)

  • Left gastro-omental artery (from splenic artery)

  • Right gastro-omental artery (from gastroduodenal artery)

  • Short gastric arteries (from splenic artery)

Venous Drainage

  • Left and right gastric veins → portal vein

  • Left gastro-omental vein → splenic vein

  • Right gastro-omental vein → superior mesenteric vein

  • Short gastric veins → splenic vein

  • Clinically relevant for porto-systemic anastomoses and varices

MRI Appearance

T1-weighted images:

  • Gastric wall appears intermediate signal; lumen variable depending on content (air = signal void, fluid = low/intermediate signal)

T2-weighted images:

  • Gastric fluid appears bright hyperintense; wall is intermediate to low signal

  • Gastritis or edema shows wall thickening with higher signal intensity

STIR:

  • Suppresses fat, highlighting wall edema, inflammation, or tumor infiltration

  • Useful in differentiating normal folds from pathologic thickening

T1 Fat-Saturated (Pre-contrast):

  • Wall shows intermediate signal against suppressed fat, aiding delineation

T1 Fat-Saturated Post-Contrast (Gadolinium):

  • Normal wall enhances homogeneously and thinly

  • Abnormalities (gastritis, tumors) show thickened, irregular, or heterogeneous enhancement

  • Essential in staging gastric carcinoma

MRI Non-Contrast 3D Imaging:

  • Provides 3D reconstruction of stomach shape, wall thickness, and relations

  • Useful for pre-surgical planning and congenital anomalies

CT Appearance

CT Pre-Contrast:

  • Stomach appears as a hollow viscus with variable contents

  • Wall normally thin (<5 mm distended)

  • Detects calcifications, masses, or hematomas

CT Post-Contrast:

  • Gastric wall enhances uniformly and thinly when normal

  • Pathologic findings:

    • Thickened, irregular wall in gastritis or malignancy

    • Hyperenhancement with edema in inflammation

    • Non-enhancing areas in necrosis or ulceration

  • Essential for gastric cancer staging, perforation detection, and bleeding evaluation

MRI images

Stomach MRI AXIAL anatomy image -img-00000-00000

MRI images

Stomach MRI coronal anatomy image -img-00000-00000

CT image

Stomach CT coronal image