Distortion-free diffusion and quantitative magnetic resonance imaging with blip up-down acquisition of spin- and gradient-echoes

A method for magnetic resonance imaging, the method comprising:

• (a) acquiring, with a magnetic resonance imaging (MRI) system, multi-contrast data using a multi-shot echo planar imaging (msEPI) pulse sequence comprising multiple shots, wherein a phase-encoding polarity is changed across the multiple shots of the msEPI pulse sequence and wherein in each shot data are acquired at a first echo time associated with a gradient echo, a second echo time associated with a mixed gradient-and-spin echo, and a third echo time associated with a spin echo;
• (b) computing field inhomogeneity data from the multi-contrast data;
• and
• (c) reconstructing an image from the multi-contrast data using the field inhomogeneity data in order to reduce geometric distortions in the reconstructed image;
• wherein computing the field inhomogeneity data comprises:
• reconstructing intermediate blip-up images from the multi-contrast data acquired in shots using a positive polarity phase-encoding;
• reconstructing intermediate blip-down images from the multi-contrast data acquired in shots using a negative polarity phase-encoding;
• and
• estimating the field inhomogeneity data from the intermediate blip-up images and the intermediate blip-down images.

A method for magnetic resonance imaging, the method comprising:

• (a) acquiring, with a magnetic resonance imaging (MRI) system, multi-contrast data using a multi-shot echo planar imaging (msEPI) pulse sequence comprising multiple shots, wherein a phase-encoding polarity is changed across the multiple shots of the msEPI pulse sequence and wherein in each shot data are acquired at a first echo time associated with a gradient echo, a second echo time associated with a mixed gradient-and-spin echo, and a third echo time associated with a spin echo;
• (b) computing field inhomogeneity data from the multi-contrast data;
• (c) reconstructing an image from the multi-contrast data using the field inhomogeneity data in order to reduce geometric distortions in the reconstructed image;
• and
• further comprising acquiring diffusion-weighted data using a second msEPI pulse sequence comprising multiple shots, wherein the phase-encoding polarity is changed across the multiple shots of the second msEPI pulse sequence and wherein in each shot data are acquired following application of diffusion encoding gradients.

A method for magnetic resonance imaging, the method comprising:

• (a) acquiring, with a magnetic resonance imaging (MRI) system, multi-contrast data using a multi-shot echo planar imaging (msEPI) pulse sequence comprising multiple shots, wherein a phase-encoding polarity is changed across the multiple shots of the msEPI pulse sequence and wherein in each shot data are acquired at a first echo time associated with a gradient echo, a second echo time associated with a mixed gradient-and-spin echo, and a third echo time associated with a spin echo;
• (b) computing field inhomogeneity data from the multi-contrast data;
• (c) reconstructing an image from the multi-contrast data using the field (c) inhomogeneity data in order to reduce geometric distortions in the reconstructed image and
• (d) denoising the image reconstructed from the multi-contrast data.