Contrast fluoroscopy
Classic X-ray examination of the stomach uses contrast agents (most commonly barium suspension) to visualize the lumen and mucosal relief.
Normally, the mucosa is represented by gastric areas (areae gastricae), which are polygonal radiolucent areas surrounded by barium-filled grooves. For detailed study, the following are used:
- Double contrast: a combination of barium and air. Allows for a detailed view of the rugae against the background of gas.
- «Flow» technique: observation of a thin layer of contrast washing over the walls as the patient turns. Helps detect small irregularities and protrusions.
Patient body position strongly affects contrast distribution: for example, lying on the back (supine) makes the gastric fundus the most posterior part.
Multislice computed tomography (MSCT)
MSCT is the leading method for staging malignant tumors. It makes it possible to evaluate the stomach in different planes (multiplanar reconstruction). CT gastnography is often used for targeted diagnostics.
Preparation and procedure features:
- Wall distention is required: using negative contrast (gas-generating crystals) or neutral contrast (about 1 liter of water before the examination).
- Intravenous contrast is mandatory to evaluate mural (intramural) masses.
- Spasmolytics are used to suppress peristalsis and reduce motion artifacts.
Scanning usually includes the late arterial phase (evaluating the wall) and the portal venous phase (searching for metastases).
MRI and PET-CT
Magnetic resonance imaging (MRI) serves as an alternative to CT for locoregional staging of cancer. Preparation is similar to CT (gastric distension with water). On T1-weighted images (T1WI), the normal wall has a three-layered structure, where the middle layer (submucosa) has a low signal.
FDG PET-CT is used to detect extragastric metastases. The method has limited value for evaluating the gastric wall itself (T-staging) because the stomach physiologically accumulates fluorodeoxyglucose (FDG).
Diagnosis of pathologies: ulcers and tumors
Helicobacter pylori plays a key role in the development of gastric diseases. This bacterium produces urease, survives in an acidic environment, and leads to gastritis, ulcers, and tumors (including MALT lymphoma).
- Gastric ulcer: a defect penetrating through the mucosa into the submucosa, and often into the muscular layer. All ulcers require monitoring until healing.
- Early gastric cancer (EGC): a tumor confined to the mucosa and submucosa.
- Advanced cancer: staged using MSCT and endosonography (EUS).
Briefly: answers to topical questions
Which anatomical parts of the stomach are evaluated during radiological examination?
Radiological examination evaluates the five main anatomical parts of the stomach.
- Cardia (cardia) connects the esophagus to the stomach, located close to the heart and the left dome of the diaphragm.
- Fundus / vault (fundus) is the rounded part located superior and posterior to the cardia.
- Body (body) is located distal to the cardia and makes up the major part of the organ.
- Antrum (antrum) is separated from the body by an imaginary line drawn from the angular notch.
- Pylorus (pylorus) is a short muscular cylindrical opening connecting the stomach to the initial part of the duodenum.
What contrast techniques are used in stomach fluoroscopy?
Single and double contrast techniques are used in stomach fluoroscopy.
- Single contrast — contrast enhancement with barium sulfate suspension.
- Double contrast — a technique in which the mucosal relief is visualized; gastric areas are defined as polygonal radiolucent areas bounded by barium-filled grooves.
- «Flow» technique (flow technique) — fluoroscopic observation of a thin layer of barium suspension washing over the mucosal surface as the patient turns.
What direct and indirect radiological signs are characteristic of a gastric ulcer?
A gastric ulcer is characterized by a direct sign and a number of indirect radiological signs.
- Direct sign — the «niche» sign on the contour or on the mucosal relief.
- Indirect signs:
- Local circular spasm of muscle fibers on the opposite wall (pointing finger sign).
- Convergence of mucosal folds toward the «niche».
- Scar-ulcerative deformation of the stomach and duodenal bulb.
- Fasting hypersecretion.
- Impairment of gastroduodenal motility.
Additionally, a benign ulcer is characterized by Hampton's line (Hampton line) — a thin radiolucent line crossing the ulcer mouth.
What complications of peptic ulcer disease can be detected by radiological methods?
The following complications of peptic ulcer disease can be detected by radiological methods:
- Perforation — transmural destruction of the wall. MSCT reveals contrast agent extravasation beyond the contour (leaking contrast), local wall thickening, and stranding of the adjacent adipose tissue (fat stranding).
- Penetration — extension of a gastric or duodenal ulcer into surrounding tissues; diagnosis is confirmed radiologically and endoscopically.
- Post-ulcer deformation / stricture — a stricture may be identified at the site of a previous ulcer, leading to persistent narrowing and deformation of the organ lumen.
- Pyloric stenosis — develops after scarring of ulcers located in the pyloric channel or the initial part of the duodenum.
Class and exam questions
Why is it necessary to distend the stomach with water or gas before CT?
Adequate distention is necessary to smooth out the folds. Without this, a normal collapsed gastric wall can mimic thickening or a tumor.
What is the difference between early and advanced gastric cancer?
Early cancer is confined to the mucosa and submucosa, regardless of the presence of lymph node metastases. Advanced cancer invades deeper.
What is the role of PET-CT in gastric cancer?
PET-CT is used mainly to search for distant metastases (extragastric involvement). Evaluation of the primary tumor itself is difficult due to the physiological background uptake of the radiopharmaceutical.
What else to study on this topic
- Pathogenesis of gastroduodenal ulcer formation and the role of H. pylori
- Virtual gastroscopy (endoluminal mode) in CT
- Differential imaging diagnosis of MALT lymphoma and carcinoma
- Endosonography (EUS) in assessing tumor invasion depth
- Interpretation of normal CT anatomy of the multi-layered gastric wall
Master the entire topic in the "Diagnostic Radiology" course
This is a summary. The course covers everything tested in classes and exams.
- Complete study guide on "Radiological Imaging Methods of the Stomach" and 2,199 more pages on the subject
- Assignments and quizzes after every topic — just like in a colloquium
- AI tutor answers questions on the topic anytime
- 10 video lessons on the subject
Other topics in the section "Diagnostic Radiology of the Abdominal Organs"
Prepared by WhiteCoat Pro faculty in accordance with the medical school curriculum. For educational purposes only.