Regularized variable density SENSE

A magnetic resonance imaging method comprising:

• acquiring variable density sensitivity encoded data with a higher density at and adjacent a center of k-space and with a lower, undersampled density away from the center of k-space using a non-Cartesian trajectory, the higher density portion of the variable density sensitivity encoded data being defined by a geometry of the non-Cartesian trajectory;
• constructing one or more regularization images from the higher density potion of the variable density sensitivity encoded data disposed at and adjacent the center of k-space;
• and
• reconstructing the variable density sensitivity encoded data into an unfolded reconstructed image, the reconstructing including:
• reconstructing the higher and lower density variable density sensitivity encoded data into a plurality of folded images, and
• unfolding the folded images to form the unfolded image using the one or more regularization images.

A magnetic resonance imaging apparatus comprising:

• a plurality of radio frequency coils acquiring variable density sensitivity encoded data including:
• a higher density portion disposed at or near the center of k-space acquired with a uniform k-space sampling density that is not undersampled, and
• undersampled k-space data acquired away from the center of k-space using a k-space sampling density that decreases smoothly with distance away from the higher density portion;
• a reconstruction processor that for each coil reconstructs:
• a regularization image reconstructed from a higher density portion of the variable density sensitivity encoded data disposed at or near a center of k-space acquired by that coil, and
• a folded image reconstructed from the variable density sensitivity encoded data acquired by that coil;
• and
• an unfolding processor that unfolds the folded images, the unfolding being regularized by the regularization images.