b value and first-order motion moment optimized data acquisition for repeatable quantitative intravoxel incoherent...

Area of Science:

• Medical Imaging
• Biophysics
• Quantitative MRI

Background:

• Intravoxel incoherent motion (IVIM) MRI allows for non-invasive assessment of liver tissue microcirculation.
• Accurate and repeatable IVIM quantification is crucial for developing reliable biomarkers for liver diseases.
• Current IVIM acquisition methods face challenges with noise and repeatability.

Purpose of the Study:

• To design and validate a b-value and first-order motion moment (M1) optimized data acquisition strategy for repeatable IVIM quantification in the liver.
• To improve the noise performance and stability of IVIM parameter estimation.

Main Methods:

• Cramer-Rao lower bound optimization was used to determine optimal monopolar and 2D sampling schemes in the b-M1 space.
• Monte Carlo simulations evaluated bias and variability of the proposed optimal samplings against conventional monopolar sampling.
• Diffusion MRI was performed in 10 volunteers using conventional monopolar, optimized monopolar, and b-M1-optimized 2D gradient waveforms.

Main Results:

• Simulations showed improved noise performance for the optimal 2D sampling compared to monopolar methods.
• The b-M1-optimized 2D acquisition demonstrated significant decreases in standard deviations and outlier percentages for diffusion coefficient, perfusion fraction, and blood velocity SD (p < 0.05).
• Good-to-excellent repeatability (ICC ≥ 0.77) was achieved for all IVIM parameters in both liver lobes using the optimized 2D acquisition.

Conclusions:

• Two-dimensional (2D) b-M1-optimized data acquisition significantly enhances the repeatability and noise performance of liver IVIM quantification.
• This optimized 2D acquisition approach holds promise for advancing the clinical establishment of IVIM quantitative biomarkers for liver diseases.