Intrafissural fat: CT correlation with chest radiography.

Area of Science:

• Radiology
• Thoracic Imaging
• Anatomical Variants

Background:

• A small collection of supradiaphragmatic fat can invaginate into the inferior aspect of the major interlobar fissure.
• This finding, termed intrafissural fat, is occasionally observed during thoracic imaging.

Purpose of the Study:

• To investigate the prevalence and imaging characteristics of intrafissural fat.
• To describe the appearance of intrafissural fat on computed tomography (CT) scans and chest radiographs.

Main Methods:

• A review of 212 computed tomography (CT) scans of the immediate supradiaphragmatic region was performed.
• The presence and characteristics of intrafissural fat were documented.
• Correlation with lateral chest radiographs was assessed.

Main Results:

• 39 out of 212 cases (18.4%) demonstrated intrafissural fat, either unilaterally or bilaterally.
• On lateral chest radiographs, intrafissural fat appeared as a sharply marginated triangular density.
• The base of the density abutted the anterior diaphragmatic surface, tapering into the major fissure.
• This triangular density was distinguishable from the heart and cardiac fat pad due to its continuity with the oblique fissure.

Conclusions:

• Intrafissural fat is a common finding in the supradiaphragmatic region.
• Its characteristic appearance on chest radiographs allows for easy differentiation from other thoracic structures.
• Radiologists should be aware of this anatomical variant to avoid misinterpretation.