METHOD FOR INCREASING SIGNAL-TO-NOISE RATIO IN MAGNETIC RESONANCE IMAGING USING PER-VOXEL NOISE COVARIANCE REGULARIZATION

摘要

A method for maximizing the signal-to-noise ratio (“SNR”) in a combined image produced using a parallel magnetic resonance imaging (“MRI”) technique is provided. The image combination used in such techniques require an accurate estimate of the noise covariance. Typically, the thermal noise covariance matrix is used as this estimate; however, in several applications, including accelerated parallel imaging and functional MRI, the noise covariance across the coil channels differs substantially from the thermal noise covariance. By combining the individual channels with more accurate estimates of the channel noise covariance, SNR in the combined data is significantly increased. This improved combination employs a regularization of noise covariance on a per-voxel basis.

主权项

1. A method for producing an image of a subject using a magnetic resonance imaging (MRI) system, the steps of the method comprising:
a) acquiring k-space data from the subject using an MRI system that includes an array of radio frequency (RF) receiver coils; b) reconstructing an Image for each receiver coil from the k-space data acquired in step a) from that receiver coil; c) estimating a noise covariance matrix for each voxel in each image reconstructed in step b); d) producing an image of the subject by weighting and combining the images reconstructed in step b) while regularizing the noise covariance matrices on a per-voxel basis.