Comparison of Improved Unidirectional Dual Velocity-Encoding MRI Methods.

Area of Science:

• Medical Imaging
• Biophysics
• Cardiovascular Imaging

Background:

• Phase-contrast (PC) MRI is crucial for assessing blood flow.
• Improving velocity-to-noise ratio (VNR) is key for robust flow quantification.
• Existing dual velocity encoding (VENC) methods like SDV and ODV aim to enhance VNR.

Purpose of the Study:

• To develop and validate a correction method for the optimal dual-VENC (ODV) approach in PC-MRI.
• To compare the performance of the corrected ODV method against other dual-VENC techniques.
• To evaluate method robustness under varying noise levels.

Main Methods:

• Utilized single-VENC protocols with background phase from high-VENC (VENC _H ) to reconstruct low-VENC (VENC _L ) phase.
• Implemented and compared unwrapping methods across different noise levels.
• Developed a specific correction for the ODV method and assessed its performance.

Main Results:

• Statistically significant interaction found between noise levels and unwrapping method performance.
• The number of non-unwrapped pixels increased with noise levels.
• The corrected ODV method demonstrated superior robustness to noise, yielding the highest number of unwrapped pixels.

Conclusions:

• All tested methods performed similarly in low-noise environments.
• The corrected ODV method is more robust to noise compared to other techniques.
• Increased computational time is a trade-off for the enhanced noise robustness of the corrected ODV method.