MO-D-213CD-01: Cartesian Methods for Rapid Time-Resolved MR Angiography.

Area of Science:

• Medical Imaging Physics
• Magnetic Resonance Imaging (MRI)
• Angiography

Background:

• The fundamental trade-off in MR imaging is between spatial and temporal resolution.
• Historically, methods like short repetition times and view sharing addressed this trade-off.
• Parallel acquisition techniques (SENSE, SMASH, GRAPPA) emerged over a decade ago to reduce acquisition time.

Purpose of the Study:

• To review physics techniques that have achieved a 20x speed improvement in MR angiography (MRA) data acquisition.
• To explain how Cartesian k-space sampling facilitates these techniques.
• To demonstrate the significant MRA image quality improvements over the last decade.

Main Methods:

• Integration of parallel acquisition methods (image and k-space based) into contrast-enhanced MRA (CE-MRA).
• Utilizing 2D parallel acquisition, which is more robust than 1D implementations.
• Employing Cartesian k-space sampling with centric view ordering for time-resolved imaging.

Main Results:

• CE-MRA applications have seen radical performance improvements due to parallel acquisition integration.
• Parallel acquisition's SNR loss is mitigated in CE-MRA by high arterial-phase signal.
• Optimized Cartesian sampling and advanced receiver coil arrays allow up to 20x reduction in sampled k-space points.

Conclusions:

• Contemporary physics techniques have significantly enhanced MRA image quality over the past decade.
• Real-time 3D image generation (within hundreds of milliseconds) is now possible.
• These advancements enable interactive guidance of medical processes through real-time imaging.