MR angiography with pulsatile flow.

Area of Science:

• Medical Imaging
• Cardiovascular Imaging
• Magnetic Resonance Imaging

Background:

• Current 3D MR angiography (MRA) methods often forgo ECG-synchronization for speed, potentially impacting image quality due to pulsatile blood flow.
• Understanding the effects of time-dependent blood flow on MRA signal intensity is crucial for optimizing imaging techniques.

Purpose of the Study:

• To investigate the consequences of pulsatile arterial blood flow on the 2D inflow magnetic resonance angiography (MRA) method.
• To develop and evaluate novel MRA data acquisition strategies to enhance image quality without significantly increasing scan times.

Main Methods:

• Utilized a 2D phase-based method with retrospective cardiac synchronization to analyze arterial blood flow and signal intensity across cardiac phases.
• Simulated alternative MRA acquisition strategies, including partial cardiac cycle data collection and cardiac-ordered phase encoding, using multiphase study raw data.
• Implemented the optimized strategy on Philips Gyroscan systems for comparison with standard non-triggered 2D inflow MRA.

Main Results:

• Demonstrated a clear correlation between blood signal intensity enhancement and time-dependent pulsatile flow.
• Simulation results indicated that combining partial cardiac cycle data acquisition and cardiac-ordered phase encoding yielded the best outcomes.
• Practical MRA studies showed significantly improved MR angiograms for highly pulsatile flow using the new method compared to standard non-triggered 2D inflow.

Conclusions:

• A novel 2D inflow MRA technique combining partial data acquisition and cardiac-ordered phase encoding effectively improves MR angiogram quality in the presence of pulsatile blood flow.
• This optimized approach offers a viable solution for achieving high-quality MRA without the prolonged scan times associated with standard cardiac triggering.