Esophageal fluoroscopy
Although fluoroscopy (Fluoroscopy) is no longer the first-line method for dysphagia, it remains indispensable for evaluating complex hiatal hernias, trauma, postoperative conditions, and examining debilitated patients.
Standard examination protocol:
- Baseline images: mandatory before contrast administration if the patient has undergone gastric or esophageal surgery.
- Standing position: double contrast technique is used. The cervical and upper thoracic segments are imaged in anteroposterior and lateral projections (4 frames per second). The middle and lower segments are imaged in the right anterior oblique projection (2 frames per second).
- Prone position: single contrast technique is applied. The physician acquires single spot films (1 frame/sec) during the swallowing of individual boluses. This is critical for assessing the distensibility of the esophagogastric junction (GOJ) and detecting wrap migration after fundoplication.
- Additional tests: in case of unexplained dysphagia, the patient may be given a barium tablet or barium-coated cookie to look for occult strictures.
Key radiological signs:
- In achalasia (Achalasia), a chest X-ray shows a dilated esophagus with a fluid-gas level.
- Malignant stricture on single-contrast imaging presents with an irregular mucosal pattern and shouldered margins.
- Benign stricture appears as a smooth and symmetric narrowing.
Endoscopic methods (EGD and EndoUS)
Esophagogastroduodenoscopy (OGD) is the method of choice for most patients. It provides direct visualization and biopsy capability. Notably, preliminary fluoroscopy can identify a pharyngeal pouch (diverticulum) and thereby prevent iatrogenic perforation during endoscope insertion.
Endoscopic ultrasound (EUS) is used primarily for cancer staging. High-frequency transducers allow differentiation of five layers of the esophageal wall:
- Mucosa (mucosa).
- Muscularis mucosae (muscularis mucosae) — hypoechoic.
- Submucosa (submucosa).
- Muscularis propria (muscularis propria) — hypoechoic.
- Adventitia (adventitia).
EndoUS also allows fine-needle aspiration biopsy (EUS-FNA) of deep structures, such as lymph nodes, and the placement of fiducial markers for radiation therapy.
Computed tomography (CT)
CT of the chest, abdomen, and pelvis is the baseline modality for staging esophageal cancer.
- Preparation details: to achieve adequate wall distension, the patient drinks 1–1.5 liters of water and takes effervescent granules. Scanning is performed in the prone position.
- Contrast enhancement: standard intravenous contrast is administered (upper abdomen scanned in arterial and portal venous phases). In trauma or Boerhaave syndrome, oral positive contrast is given (strictly low-osmolar).
- When a tracheoesophageal fistula is suspected, unenhanced scanning without oral contrast, evaluating images in the lung window, is most informative.
Radionuclide diagnostics and PET-CT
- 18F-FDG PET/CT is the standard for radical treatment planning in cancer. The method outperforms all others in detecting occult metastases. The presence of FDG-avid (FDG-avid) lymph nodes is of paramount prognostic significance.
- Technetium (99mTc) scintigraphy is used for functional evaluation: diagnosis of gastro-oesophageal reflux disease (GORD) and motility disorders. The patient is asked to swallow a radiolabelled liquid (sulphur colloid) or solid food (scrambled eggs with the isotope).
- Note: magnetic resonance imaging (MRI) is not used in routine practice to evaluate the oesophagus due to pronounced artefacts from respiration, peristalsis and heartbeat.
Briefly: answers to topical questions
What are the absolute contraindications to the use of barium suspension in oesophageal fluoroscopy?
Contraindications to the use of barium suspension include:
- hypersensitivity to the drug;
- gastrointestinal perforation or suspected gastrointestinal perforation;
- disorders of the swallowing act;
- intestinal obstruction and constipation;
- oesophageal stenosis;
- gastrointestinal bleeding;
- early postoperative period following gastrointestinal surgery;
- malabsorption syndrome and food allergy;
- oesophagotracheal fistulae.
What types of esophageal diverticula are distinguished depending on their localization?
Depending on localization, the following are distinguished:
- bifurcation diverticula — localized at the Th3–Th5 level; right-sided lateral thoracotomy is used;
- supradiaphragmatic or epiphrenic diverticula — operated via thoracotomy in the seventh intercostal space on the right or left depending on localization;
- pharyngeal pouches (diverticula), which may be detected in severe dysphagia.
Which lymph node groups are affected in lymphogenous metastasis of thoracic oesophageal cancer?
In lymphogenous metastasis of oesophageal cancer, both regional and distant lymph node groups are affected. Regional nodes include:
- Perioesophageal (perioesophageal) — including cervical nodes.
- Bifurcation (subcarinal) — or subcarinal.
- Left gastric (left gastric) — nodes of the corresponding zone.
- Coeliac (coeliac) — nodes of the coeliac trunk.
Non-regional (metastatic) nodes include:
- Supraclavicular (supraclavicular) — the left node is more frequently affected.
- Retroperitoneal abdominal — abdominal cavity nodes.
What postoperative complications of fundoplication can be detected by oesophageal fluoroscopy in the supine position?
Oesophageal fluoroscopy in the prone position with single contrast can detect wrap migration. This examination is critically important when this postoperative complication of fundoplication is suspected. During the procedure, the motility and distensibility of the oesophagogastric junction are assessed during three separate swallows.
To memorize the 5 layers of the oesophageal wall on EUS, remember the "muscle layer rule": the muscularis mucosae (2nd layer) and the muscularis propria (4th layer) always appear dark (hypoechoic). The remaining layers are bright.
Class and exam questions
Why is esophageal fluoroscopy also performed in the prone position?
This is necessary to assess the motility and distensibility of the esophagogastric junction. The prone position allows for a better study of contrast transit dynamics, which is critically important when migration of the wrap is suspected following fundoplication.
What is the difficulty in assessing lymph nodes in esophageal cancer via CT?
Malignant lymph nodes in esophageal cancer are often not enlarged and may be located at a significant distance from the primary tumor. Therefore, for accurate staging, CT is mandatory supplemented by EUS and PET-CT.
Which diagnostic imaging method is applied first when a tracheoesophageal fistula is suspected?
Usually, non-contrast computed tomography viewed in a lung window is performed—this is often sufficient for initial qualitative visualization of the fistula.
What else to study on this topic
- Radiological presentation of hiatal hernias.
- Algorithm for the differential diagnosis of benign and malignant esophageal strictures.
- Endoscopic mucosal resection (EMR): technique and role in early tumor staging.
- Application of radiofrequency ablation (RFA) and botulinum toxin in esophageal pathologies.
- Histological features and epidemiology of adenocarcinoma and squamous cell carcinoma.
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Other topics in the section "Diagnostic Radiology of the Abdominal Organs"
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