Method and system for improved magnetic resonance imaging
Magnetic resonance imaging systems and methods are provided for time-efficiently producing a plurality of image contrasts, the plurality of image contrasts including a first contrast being coupled with a second contrast and acquired over a plurality of key parameters that govern the second contrast to which the first contrast is coupled. In addition, the plurality of image contrasts is used to simultaneously map the first contrast, the second contrast, and additional contrasts.
1 . A magnetic resonance image (MRI) capture method comprising the steps of:
generating a single pulse sequence to produce a plurality of image contrasts, the plurality of image contrasts comprising at least a first contrast coupled with a second contrast;
acquiring the plurality of image contrasts, wherein the plurality of image contrasts correspond to diffusion-weighted each images, diffusion-weighted image being acquired with a train of gradient echoes consistent with echo-planar imaging and at a specific effective echo time (TE eff ), wherein the TE eff is defined as the echo time (TE) when k-space center is sampled, and wherein each gradient-echo train comprises a shortened train of echoes to produce an image over a reduced field-of-view; and
capturing and producing an image.
2 . The MRI capture method of claim 1 , wherein the plurality of image contrasts is used for simultaneous parametric mapping of apparent diffusion coefficient, T1 relaxation time, T2* relaxation time, and/or T2 relaxation time.
3 . The MRI capture method of claim 1 , wherein a gradient blip pulse is applied along a phase-encoding direction between adjacent echo trains to re-position the start point of the k-space trajectory for a next echo-train acquisition.
4 . The MRI capture method of claim 1 , wherein each gradient-echo train comprises a shortened train of echoes by employing parallel imaging, sparse k-space sampling, segmented k-space acquisition or a combination thereof.
5 . The MRI capture method of claim 1 , wherein the plurality of image contrasts is used in an intra-voxel incoherent motion (IVIM) diffusion model and extensions thereof.
6 . The MRI capture method of claim 1 , wherein the plurality of image contrasts is used to study coupling between diffusion and relaxation times in materials or biological tissues, thereby inferring material or tissue microstructures.
7 . The MRI capture method of claim 1 , wherein the first contrast is a diffusion-weighted contrast and the second contrast is a contrast weighted by spin-spin relaxation time (T2).
8 . The MRI capture method of claim 7 , wherein a plurality of TE or TEeff are generated by a train of radiofrequency (RF) refocusing pulses, each RF refocusing pulse producing a spin echo from which the train of gradient echoes are acquired.
9 . The MRI capture method of claim 1 , wherein the first contrast is a diffusion-weighted contrast and the second contrast is an apparent spin-spin relaxation time-weighted contrast (T2*-weighted contrast).
10 . The MRI capture method of claim 9 , wherein a plurality of TE or TEeff are produced by a plurality of trains of gradient echoes.
11 . The MRI capture method of claim 10 , wherein the plurality of trains of gradient echoes is acquired at, about, or immediately after the formation of a stimulated echo.
12 . The MRI capture method of claim 10 , wherein the plurality of trains of gradient echoes are acquired at, about, or immediately after the formation of a spin echo.
13 . A magnetic resonance imaging (MRI) system comprising:
an MRI scanner comprising image contrast data acquisition coils configured to produce a plurality of image contrasts over a reduced field-of-view, the plurality of image contrasts comprising a first contrast coupled with a second contrast; and
an image processing component operably connected to the MRI scanner and configured to receive and process the plurality of image contrasts from the image contrast data acquisition coils to produce an image.
14 . The system of claim 13 wherein the image is produced by the method of claim 1 .