Computed tomographic detection of retrocrural air

Area of Science:

• Radiology
• Thoracic Imaging
• Anatomy

Background:

• The prevertebral space at the diaphragmatic crura normally contains vascular and lymphatic structures.
• Gas in this retrocrural space can be mistaken for pathology.

Purpose of the Study:

• To identify and characterize the presence of normal lung tissue within the retrocrural space on computed tomography (CT) scans.
• To differentiate normal retrocrural air from pathological findings.

Main Methods:

• Retrospective review of three computed tomography (CT) cases with retrocrural gas.
• Prospective evaluation of 100 consecutive CT examinations to determine the incidence of retrocrural air.

Main Results:

• Three patients demonstrated gas in the retrocrural space, identified as normal lung parenchyma.
• Prospective analysis revealed retrocrural air in 3% of the 100 evaluated CT scans.
• Distinguishing normal retrocrural air from free retroperitoneal air or abscess-related gas is crucial.

Conclusions:

• Insinuation of normal lung into the retrocrural space is a potential finding on CT.
• The presence of retrocrural air in 3% of cases highlights its significance.
• Radiologists must be aware of this normal variant to avoid misdiagnosis of retroperitoneal pathology.