Bochdalek hernia

Imaging findings in Bochdalek hernia

Basic diagnostic imaging modalities are used to confirm the presence of a Bochdalek hernia. On a standard lateral chest radiograph, the pathology is identified as a localized bulging of the diaphragmatic contour. This bulging is located directly above the posterior costophrenic recess (posterior costophrenic recess).

Computed tomography (CT) provides a more detailed picture. A tissue defect is visualized in the posteromedial aspect of the left hemidiaphragm (hemidiaphragm). Directly adjacent to this defect is a characteristic fatty mass herniating into the thoracic cavity, which serves as a reliable diagnostic marker for this pathology.

Traumatic diaphragmatic rupture

Unlike a classic hernia, traumatic diaphragmatic rupture (Traumatic Diaphragmatic Rupture) is accompanied by an acute disruption of the integrity of the muscular barrier.

On a plain chest radiograph, this condition manifests as pronounced opacification (opacification) of the lower portion of the right hemithorax. At the same time, the normal contour of the diaphragmatic dome completely disappears. A strict and undeniable sign of rupture in a patient with acute trauma is a follow-up radiograph showing progressive opacification of one of the halves of the chest by a gas-filled structure (displaced hollow organs).

Multidetector computed tomography (MSCT / MDCT) is the gold standard. The main diagnostic criterion on MSCT is the detection of abdominal organs directly within the pleural space. Coronal and sagittal reconstructions frequently demonstrate consolidation of the lower lobe of the right lung and bulging (bulging) of the liver tissue into the thoracic cavity.

Specific CT signs of rupture

When analyzing tomograms, it is important to pay attention to two classic signs indicating rupture and liver displacement:

• 'Hump sign' ('hump sign'): visualized on the sagittal slice. The posterior part of the hepatic herniation appears compressed by the rigid edges of the ruptured diaphragm.
• 'Band sign' ('band sign'): identified on the coronal slice. It appears as a characteristic linear lucency (linear lucency) running across the liver tissue strictly along the ruptured edges of the diaphragmatic dome.

Alternative and auxiliary diagnostic methods

In addition to CT and basic radiography, other methods may be used (или historically were used) in clinical practice, each with its own limitations:

1. Nasogastric tube. Assessing its position on a radiograph helps localize the gastric fundus (gastric fundus). However, the method does not provide direct information on the position of the diaphragm itself, which is critical for definitively confirming a rupture.
2. Barium contrast studies (Barium studies). Currently used extremely rarely due to the wide availability of CT. They can reveal extrinsic narrowing (extrinsic narrowing) at the border of the stomach or bowel loops where they pass through the diaphragmatic defect. Strictly contraindicated in emergency situations.
3. Artificial pneumoperitoneum (Artificial pneumoperitoneum). A small volume of air is introduced into the abdominal cavity. If this air passes through the rupture and causes a pneumothorax, the diagnosis is confirmed. Limitation of the method: if the defect is closed by adhesions (adhesions) or incarcerated herniated organs, air will not migrate; it will merely outline the diaphragm from below.
4. Ultrasonography (US). The method is diagnostically valuable only if both the diaphragm itself and the herniated organs can be clearly visualized. Examination of the right dome is technically easier because the liver serves as an excellent acoustic window (acoustic window). The main limitations of US include minimal visibility of the diaphragm itself, marked tenderness (tenderness) in the upper abdomen upon probe pressure, and the presence of gas in displaced bowel loops that obstructs the view.

Briefly: answers to topical questions

Class and exam questions

What else to study on this topic

• Normal and pathological radioanatomy of the costophrenic recesses
• Comparison of the diagnostic yield of coronal and sagittal CT reconstructions in hernias
• Mechanism of formation of the 'hump' and 'band' signs in ruptures
• Limitations of ultrasound in visualizing thoracic and abdominal organs
• Management tactics for patients with progressive hemithorax opacification

Other topics in the «Chest Radiology» section

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