Validating Automated Kidney Stone Volumetry in CT and Mathematical Correlation with Estimated Stone Volume Based on...

Area of Science:

• Urology
• Medical Imaging
• Software Validation

Background:

• Kidney stone burden is typically assessed by maximum diameter, which can be biased due to non-spherical stone shapes.
• Automated stone volumetry offers a more accurate alternative to diameter-based measurements.

Purpose of the Study:

• To validate the AutoMated UroLithiasis Evaluation Tool (AMULET) software for kidney stone volumetry.
• To compare AMULET's performance against standard clinical practices for stone size assessment.

Main Methods:

• Ninety-six urinary stones were measured for maximum diameter and volume by urologists as a reference standard.
• CT scans of stones in a phantom were analyzed by radiologists using manual and automated measurements.
• An "expected volume" was calculated using manual diameter measurements.

Main Results:

• Automated volumetry showed a high correlation (0.99) with reference volumes, surpassing manual diameter-based calculations (0.95).
• Automated diameter measurements had a strong correlation (0.91) with reference diameters, though slightly lower than manual measurements (0.98).
• Automated stone volumetry is significantly more accurate than diameter-based volumetric calculations.

Conclusions:

• Automated stone volumetry, as performed by AMULET software, is highly accurate and recommended for clinical trials to avoid bias.
• While automated diameter measurements are accurate, automated volumetry provides superior precision for assessing kidney stone burden.