Method of improved multiple-phase dynamic contrast-enhanced magnetic resonance imaging with motion correction using water/fat signal separation
A method of operating a magnetic resonance imaging system ( 10 ) with regard to acquiring multiple-phase dynamic contrast-enhanced magnetic resonance images, the method comprising steps of acquiring ( 48 ) a first set of magnetic resonance image data (x pre ) prior to administering a contrast agent to the subject of interest ( 20 ), by employing a water/fat magnetic resonance signal separation technique, determining ( 52 ) a first image of the spatial distribution of fat (I pre ) of at least the portion of the subject of interest ( 20 ), acquiring ( 50 ) at least a second set of magnetic resonance image data (x 2 ) of at least the portion of the subject of interest ( 20 ) after administering the contrast agent to the subject of interest ( 20 ), by employing a water/fat magnetic resonance signal separation technique, determining ( 54 ) at least a second image of the spatial distribution of fat (I 2 ph ) of at least the portion of the subject of interest ( 20 ), applying ( 56 ) an image registration method to the second image of the spatial distribution of fat (I 2 ph ) with reference to the first image of the spatial distribution of fat (I pre ) for correcting a potential motion of the subject of interest ( 20 ); and a magnetic resonance imaging system ( 10 ) having a control unit ( 26 ) that is configured to carry out steps ( 56 - 64 ) of such a method; and a software module ( 44 ) for carrying out such a method, wherein the method steps ( 56 - 64 ) to be conducted are converted into a program code that is implementable in a memory unit ( 30 ) and is executable by a processor unit ( 32 ) of the magnetic resonance imaging system ( 10 ).
1. A method of operating a magnetic resonance imaging system with regard to acquiring multiple-phase dynamic contrast-enhanced magnetic resonance images, the magnetic resonance imaging system being configured for acquiring magnetic resonance images of at least a portion of a subject of interest, the method comprising:
acquiring a first set of magnetic resonance image data (xpre) of the at least a portion of the subject of interest prior to administering a contrast agent to the subject of interest;
determining a first image of a spatial distribution of fat (Ipre) of the at least a portion of the subject of interest from the first set of magnetic resonance image data (xpre) using a water/fat magnetic resonance signal separation technique;
acquiring a plurality of additional sets magnetic resonance image data (xi) of the at least a portion of the subject of interest after administering the contrast agent to the subject of interest;
determining a plurality of images of the spatial distribution of fat (Iiph) of the at least a portion of the subject of interest from the plurality of additional sets of magnetic resonance image data (xi) using the water/fat magnetic resonance signal separation technique;
applying an image registration method to each of the plurality of images of the spatial distribution of fat (Iiph) with reference to the first image of the spatial distribution of fat (Ipre) to determine transformations for minimizing differences between the plurality of images of the spatial distribution of fat (Iiph) and the first image of the spatial distribution of fat (Ipre); and
applying the determined transformations to the plurality of additional sets of magnetic resonance image data (xi) for correcting for motion of the subject of interest in magnetic resonance images reconstructed from the additional sets of magnetic resonance image data (xi), respectively, the motion having occurred in times between acquiring the first set of magnetic resonance image data (xpre) and acquiring the additional sets of magnetic resonance image data (xi).
2. The method of claim 1 wherein the water/fat magnetic resonance signal separation technique is based on a difference in Larmor frequencies of excited nuclei due to chemical shift.
3. The method of claim 1 , wherein the additional sets of magnetic resonance image data (xi) acquired after administering the contrast agent are obtained using a compressed sensing method.
4. The method of claim 1 , further comprising applying a filter to the first set of magnetic resonance image data (xpre) acquired prior to administering the contrast agent to the subject of interest, wherein the filter is equivalent to a high pass filter in k-space.
5. A magnetic resonance imaging system configured for acquiring magnetic resonance images of at least a portion of a subject of interest, comprising:
an examination space configured for positioning the at least a portion of the subject of interest within;
a main magnet configured for generating a static magnetic field in the examination space;
a magnetic gradient coil system configured for generating gradient magnetic fields superimposed to the static magnetic field;
at least one transmitting radio frequency antenna device configured for applying a radio frequency excitation field to nuclei of or within the at least a portion of the subject of interest for magnetic resonance excitation;
at least one receiving radio frequency antenna device configured for receiving magnetic resonance signals from the nuclei of or within the portion of the subject of interest that have been excited by applying the radio frequency excitation field;
a controller, comprising memory and at least one processor, configured for controlling functions of the magnetic resonance imaging system, wherein the memory stores instructions that, when executed by the at least one processor, cause the at least one processor to perform a process comprising:
receiving a first set of magnetic resonance image data (xpre) of the at least a portion of the subject of interest acquired prior to administering a contrast agent to the subject of interest;
determining a first image of a spatial distribution of fat (Ipre) of the at least a portion of the subject of interest from the first set of magnetic resonance image data (xpre) using a water/fat magnetic resonance signal separation technique;
receiving a plurality of additional sets of magnetic resonance image data (xi) of the at least a portion of the subject of interest acquired after administering the contrast agent to the subject of interest;
determining a plurality of images of the spatial distribution of fat (Iiph) of the at least a portion of the subject of interest from the plurality of additional sets of magnetic resonance image data (xi) using the water/fat magnetic resonance signal separation technique;
applying an image registration method to each of the plurality of images of the spatial distribution of fat (Iiph) with reference to the first image of the spatial distribution of fat (Ipre) to determine transformations for minimizing differences between the plurality of images of the spatial distribution of fat (Iiph) and the first image of the spatial distribution of fat (Ipre); and
applying the determined transformations to the received plurality of additional sets of magnetic resonance image data (xi) for correcting for motion of the subject of interest in magnetic resonance images reconstructed from the additional sets of magnetic resonance image data (xi), respectively, the motion having occurred in times between acquiring the first set of magnetic resonance image data (xpre) and acquiring the additional sets of magnetic resonance image data (xi).
6. The system of claim 5 , wherein the water/fat magnetic resonance signal separation technique is based on a difference in Larmor frequencies of excited nuclei due to chemical shift.
7. The system of claim 5 , wherein the additional sets of magnetic resonance image data (xi) acquired after administering the contrast agent are obtained using a compressed sensing method.
8. The system of claim 5 , wherein the process performed by the at least one processor further comprises:
applying a filter to the first set of magnetic resonance image data (xpre) acquired prior to administering the contrast agent to the subject of interest, wherein the filter is equivalent to a high pass filter in k-space.
9. A non-transitory computer readable medium storing instructions for controlling acquisition of multiple-phase dynamic contrast-enhanced magnetic resonance images of at least a portion of a subject of interest, the instructions, when executed by a computer processor, causing the computer processor to perform a method comprising:
receiving a first set of magnetic resonance image data (xpre) of the at least a portion of the subject of interest acquired prior to administering a contrast agent to the subject of interest;
determining a first image of a spatial distribution of fat (Ipre) of the at least a portion of the subject of interest from the first set of magnetic resonance image data (xpre) using a water/fat magnetic resonance signal separation technique;
receiving a plurality of additional sets of magnetic resonance image data (xi) of the at least a portion of the subject of interest acquired after administering the contrast agent to the subject of interest;
determining a plurality of images of the spatial distribution of fat (Iiph) of the at least a portion of the subject of interest from the plurality of additional sets of magnetic resonance image data (xi) using the water/fat magnetic resonance signal separation technique;
applying an image registration method to each of the plurality of images of the spatial distribution of fat (Iiph) with reference to the first image of the spatial distribution of fat (Ipre) to determine transformations for minimizing differences between the plurality of images of the spatial distribution of fat (Iiph) and the first image of the spatial distribution of fat (Ipre); and
applying the determined transformations to the received plurality of additional sets of magnetic resonance image data (xi) to correct for motion of the subject of interest in magnetic resonance images reconstructed from the additional sets of magnetic resonance image data (xi), respectively, the motion having occurred in times between acquiring the first set of magnetic resonance image data (xpre) and acquiring the additional sets of magnetic resonance image data (xi).