A simplified CT-volumetry method for the canine liver

Area of Science:

• Veterinary Radiology
• Medical Imaging Analysis
• Comparative Anatomy

Background:

• Computed tomographic (CT) liver volumetry using the slice addition technique is accurate but time-consuming.
• Standard DICOM software limits contouring to one area per image, complicating transverse plane analysis of separated liver lobes.

Purpose of the Study:

• To evaluate the accuracy of hepatic contouring using sagittal reformatting and a reduced number of CT images for canine liver volumetry.
• To determine if a simplified CT liver volumetry method yields comparable results to traditional techniques.

Main Methods:

• Prospective, experimental methods comparison study involving five canine cadavers.
• CT scans were reviewed using sagittal reformatting, with liver contouring performed on image stacks of varying sizes (9 to 60 images).
• Liver volume was calculated via CT volumetry and compared to ex vivo water displacement measurements.

Main Results:

• Excellent interobserver agreement was achieved (intraclass correlation coefficient = 0.957).
• No significant difference was found between CT-derived liver volumes and water displacement volumes across all image stack sizes.
• Accurate results were obtained even with as few as nine reformatted images.

Conclusions:

• Hepatic contouring using sagittally reformatted CT images and a reduced image set is an accurate and simplified method for canine liver volumetry.
• This approach offers a time-efficient alternative to traditional slice addition techniques for assessing canine liver volume.