Inverted contrast medium-urine layering in the canine urinary bladder on computed tomography

Area of Science:

• Radiology
• Urogenital Imaging
• Computed Tomography (CT)

Background:

• Contrast medium-urine layering is a common finding on transverse CT scans of the urinary bladder.
• Typically, contrast-opacified urine layers dependently, with non-opacified urine above it.
• This layering occurs after intravesicular or intravenous administration of iodinated contrast medium.

Purpose of the Study:

• To describe three cases of inverted contrast medium layering in human patients.
• To review this phenomenon in humans.
• To propose an explanation for similar imaging findings in dogs.

Main Methods:

• Retrospective study of three human patients.
• Review of existing literature on contrast medium-urine layering.
• Analysis of CT imaging findings.

Main Results:

• Three cases of inverted contrast medium layering were identified in human patients following intravenous contrast administration.
• The typical layering pattern was reversed in these cases.
• A potential explanation for the inverted layering in dogs was proposed based on human findings.

Conclusions:

• Inverted contrast medium layering, though uncommon, can occur in humans.
• Understanding this phenomenon is crucial for accurate interpretation of urinary bladder CT scans.
• The findings may provide insights into comparative urogenital imaging between humans and canines.