Simultaneous Multi-VENC and Simultaneous Multi-Slice Phase Contrast Magnetic Resonance Imaging.

Area of Science:

• Magnetic Resonance Imaging
• Biomedical Engineering
• Cardiovascular Imaging

Background:

• Phase contrast (PC) MRI is crucial for quantifying blood flow.
• Simultaneous multi-slice (SMS) imaging accelerates MRI acquisition.
• Acquiring multiple velocity encodings (VENCs) is essential for comprehensive flow assessment.

Purpose of the Study:

• To develop a novel simultaneous multi-VENC and multi-slice (SMV+SMS) imaging technique for phase contrast MRI.
• To enable robust quantification of a wide range of blood flow velocities in a single scan.
• To improve spatial coverage and reduce artifacts in PC MRI.

Main Methods:

• A novel pulse sequence was designed for concurrent acquisition of multiple VENCs and slices.
• Effective echo times for multiple VENCs were controlled by adjusting gradient area.
• Multiband radiofrequency (RF) pulses were used for simultaneous slice excitation.
• RF phase cycling and gradient blips facilitated VENC and slice separation.
• Acquired k-space data was reformulated into a 3D undersampled k-space for artifact reduction.

Main Results:

• In vivo studies demonstrated comparable performance to conventional PC MRI for low and high flow velocities.
• The proposed method achieved high spatial coverage without apparent artifacts.
• It clearly depicted flow signals above the VENC value, outperforming the conventional method.
• Improved velocity dynamic range and velocity-to-noise ratio (VNR) were observed.

Conclusions:

• The developed SMV+SMS technique offers a robust and efficient approach for PC MRI.
• It provides high-quality imaging of diverse flow velocities across cardiac phases.
• This method enhances diagnostic capabilities in cardiovascular imaging by improving velocity dynamic range and spatial coverage.