Projection-based estimation and nonuniformity correction of sensitivity profiles in phased-array surface coils.

Area of Science:

• Magnetic Resonance Imaging (MRI)
• Medical Imaging Technology
• Coil Sensitivity Profiling

Background:

• Phased-array coils are crucial for parallel MRI, but their sensitivity profiles can cause image intensity nonuniformity.
• Existing methods like sum-of-squares (SOS) have limitations in correcting these nonuniformities.
• Accurate sensitivity profiles are essential for high-quality parallel MRI reconstruction.

Purpose of the Study:

• To develop a novel method for calculating accurate sensitivity profiles of phased-array coils.
• To correct nonuniform intensity in parallel MRI using the calculated sensitivity profiles.
• To improve the uniformity of images acquired with phased-array coils.

Main Methods:

• Estimating accurate sensitivity profiles by fitting nonlinear curves to projection views.
• Utilizing nonlinear curve-fitting to isolate low-frequency sensitivity information.
• Employing filtered back-projection (FBP) to compute channel-specific sensitivity profiles.
• Applying the method to phantom and human brain images.

Main Results:

• The proposed method achieved more uniform image intensity compared to the SOS approach.
• Intensity variation was reduced from 13.1% (SOS) to 6.1% with the new method.
• The approach improved reconstructed image uniformity when used for sensitivity encoding (SENSE).

Conclusions:

• The novel method is more effective than conventional SOS for correcting phased-array coil image intensity nonuniformity.
• The technique demonstrates resilience to noise.
• Successful application in parallel imaging reconstruction highlights its utility.