Multiple region MRI

Area of Science:

• Medical Imaging
• Magnetic Resonance Imaging
• Signal Processing

Background:

• Traditional Fourier MR imaging (FT MRI) relies on the Whittaker-Kotel'nikov-Shannon (WKS) sampling theorem.
• The WKS theorem dictates spatial frequency sampling for full field-of-view (FOV) image reconstruction.
• Conventional FT MRI requires extensive k-space data acquisition.

Purpose of the Study:

• To generalize the WKS theorem for optimal k-space sampling in specific image regions.
• To introduce and validate the multiple region MRI (mrMRI) technique.
• To enable efficient MR imaging of localized signals or edges within the FOV.

Main Methods:

• Developed a generalized sampling strategy for images vanishing in multiple, non-adjacent regions.
• Implemented mrMRI for acquiring images using a fraction of WKS-required k-space samples.
• Demonstrated mrMRI using 3D MR angiography (MRA) of carotid arteries.

Main Results:

• mrMRI reconstructs images efficiently without noise amplification, comparable to conventional FT MRI.
• The method allows for increased temporal or spatial resolution when signals are confined to small regions.
• Successfully acquired Gd-enhanced first-pass 3D MRA images without bolus-timing.

Conclusions:

• mrMRI provides a more efficient sampling strategy than conventional FT MRI for specific imaging scenarios.
• This technique enhances resolution and speed, particularly for localized signals or edges.
• mrMRI has broad applications in MR angiography, interventional MRI, and functional MRI.