New calibration setup for quantitative DCE-US imaging protocol: Toward standardization.

Area of Science:

• Medical Imaging
• Ultrasound Technology
• Quantitative Biomarkers

Background:

• Dynamic Contrast-Enhanced Ultrasonography (DCE-US) offers quantitative biomarkers for monitoring anti-angiogenic cancer treatments, complementing morphological assessments.
• Standardization issues arise when applying DCE-US protocols across different ultrasound scanner generations, probes, and settings.
• Existing methods primarily rely on morphological changes, necessitating quantitative imaging for consistent patient follow-up.

Purpose of the Study:

• To develop a novel, reproducible, and cost-effective calibration setup for transposing DCE-US imaging protocols to newer ultrasound scanner generations.
• To validate the calibration method using both abdominal and linear probes.

Main Methods:

• A concentration splitter was employed to generate four simultaneous contrast agent concentrations (12.5% to 100%) for measuring harmonic signal intensity variations.
• The Area Under the time-intensity Curve (AUC) was calculated for each concentration to determine the slope, serving as the calibration parameter.
• Two ultrasound scanners (Aplio500 and Aplioi900) were calibrated by adjusting Mechanical Index (MI) and Color Gain (CG) settings to achieve matching slopes.

Main Results:

• The calibration setup demonstrated excellent measurement repeatability (96.8%).
• Post-calibration, excellent reproducibility was achieved, with quantitative measurement agreement between scanners ranging from 95.4% to 98.8%.
• Validated settings for the Aplioi900 were determined: Abdominal probe (MI=0.13, CG=34 dB) and Linear probe (MI=0.10, CG=38 dB).

Conclusions:

• The developed calibration setup provides reliable measurements for quantitative imaging.
• It facilitates the rapid transfer and consistent application of DCE-US protocols to new ultrasound scanners.
• This enables uninterrupted therapeutic evaluation of patients undergoing anti-angiogenic treatments.