Blunt traumatic diaphragmatic hernia: Pictorial review of CT signs

Abstract

Blunt diaphragmatic rupture rarely accounts for immediate mortality and may go clinically silent until complications occur which can be life threatening. Although many imaging techniques have proven useful for the diagnosis of blunt diaphragmatic rupture, multidetector CT (MDCT) is considered to be the reference standard for the diagnosis of diaphragmatic injury. Numerous CT signs indicating blunt diaphragmatic rupture have been described in literature with variable significance. Accurate diagnosis depends upon the analysis of all the signs rather than a single sign; however, the presence of blunt diaphragmatic rupture should be considered in the presence of any of the described signs. We present a pictorial review of various CT signs used to diagnose blunt diaphragmatic injury. Multiplanar reconstruction is very useful; however, predominantly axial sections have been described in this pictorial review as the images shown are from dual-slice CT.

Keywords: Computed tomography; diaphragm; hernia; injury; trauma.

Figure 1(A and B)

(A) Normal diaphragmatic crura: (A) The crura (arrowhead) are noted on either side of the vertebra and are well delineated when in contact with fat. The medial arcuate ligament (arrow) is seen as a thin isodense band superior to the celiac axis (B) The lateral arcuate ligament (arrow) may be visible on CT scans as it courses toward the 12^th rib

Figure 2

Right diaphragmatic hernia. A 77-year-old male patient with history of a road side accident 3 years ago presented with breathlessness. Contrast-enhanced axial CT image shows herniation of the liver (White arrow) and the colon (Black Arrow) through a right-side diaphragmatic rupture

Figure 3

Diaphragm discontinuity sign and dangling diaphragm sign: A 45-year-old male patient with history of motor bike accident 4 months ago presented with pain chest and cough. Axial contrast-enhanced CT image of upper abdomen reveals diaphragm discontinuity sign (white arrows) and dangling diaphragm sign (double white arrows)

Figure 4

Segmental non-visualization of diaphragm. A 35-year-old female patient with history of fall from height 1 year ago presented with pain and vomiting. Axial contrast-enhanced CT image of upper abdomen reveals segmental non-visualization of diaphragm - only a part of the left crus is noted (arrow) and the rest of the diaphragm is not visualized

Figure 5

Dependent viscera sign. A 62-year-old male patient with history of motor bike accident 6 months ago presented with dyspnea. Axial contrast-enhanced CT image of chest reveals the stomach and bowel loops herniating into the thorax. The contrast-filled stomach is in direct contact with the posterior thoracic wall (Black arrow) (dependent viscera sign)

Figure 6

Intrathoracic herniation of the abdominal viscera. A 40-year-old male patient with history of motor vehicle accident 6 months ago presented with breathlessness. Axial CT image of chest reveals intrathoracic herniation of bowel loops (Black arrow) and stomach (White arrow) into the left hemithorax secondary to post-traumatic diaphragmatic rupture

Figure 7

A 35-year-old man with history of blunt trauma 12 years ago presented with breathlessness. Coronal CT image reveals herniation of stomach and small bowel loops (black arrow) in the left hemithorax through the large defect in the left diaphragm due to its rupture

Figure 8

Collar sign: Same patient as in Figure 3. Axial CECT image of upper abdomen shows luminal narrowing of the herniated stomach at the site of the diaphragmatic tear (arrows)

Figure 9

Elevated abdominal organs: Same patient as in Figure 2. CT topogram reveals elevation of liver and large bowel loops (Black arrows) on the right side

Figure 10

Thoracic fluid abutting abdominal viscera. A 37-year-old male patient with history of trauma few days ago presented in the emergency with features of intestinal obstruction. Axial contrast-enhanced CT image of upper abdomen reveals left pleural effusion that is abutting the herniated bowel (arrow)

Figure 11

Hypoattenuated hemidiaphragm: Same patient as in Figure 6. Axial plain CT image of abdomen reveals hypodense and thickened left crus (white arrow) as compared to the right crus

Figure 12

A 37-year-old male patient with history of trauma few days ago presented in the emergency with features of intestinal obstruction. CT topogram reveals a dilated air-filled large bowel herniating into the left hemithorax. The site of obstruction (arrow) is seen as an abrupt cut-off of the air column at the level of the diaphragm

Figure 13

Tension gastrothorax. A 30-year-old male patient with history of trauma a month ago presented with vomiting and breathlessness. CT topogram and coronal image show evidence of air within the left hemithorax (air in dilated stomach) (white arrow) with absence of lung markings within, collapse of underlying lung, and mediastinal shift, similar to pneumothorax. However, in this case, the collapsed lung is pushed superiorly (black arrow) suggesting a diaphragmatic hernia, as opposed to a pneumothorax in which the lung is pushed inferiomedially