Magnetic resonance imaging apparatus
View Patent ↗In an MRI apparatus, an executing unit executes an image taking sequence according to a parallel imaging method so as to collect MR signals by using a plurality of RF coils; a reconstructing unit reconstructs an MR image from the MR signals; an unfolding processing unit performs an unfolding process to unfold aliasing that has occurred in the MR image, by using sensitivity distribution data indicating a spatial sensitivity distribution of the RF coils; a judging unit judges whether the unfolded image includes one or more pixels of which the pixel values are abnormal; and when the judgment result is in the affirmative, a correcting unit corrects the sensitivity distribution data so that the pixel values of the pixels become closer to a normal value. After the sensitivity distribution data has been corrected, the unfolding processing unit performs the unfolding process again by using the corrected sensitivity distribution data.
1. A magnetic resonance imaging apparatus comprising:
an executing unit that executes an image taking sequence according to a parallel imaging method so as to collect magnetic resonance signals by using a plurality of radio frequency coils;
a reconstructing unit that reconstructs a magnetic resonance image from the magnetic resonance signals;
an unfolding processing unit that performs an unfolding process so as to unfold aliasing that has occurred in the magnetic resonance image, by using sensitivity distribution data indicating a spatial sensitivity distribution of the radio frequency coils;
a judging unit that judges whether the unfolded image obtained as a result of the unfolding process includes one or more pixels of which pixel values are abnormal; and
a correcting unit that, in a case where the judging unit has judged that the unfolded image includes one or more pixels of which the pixel values are abnormal, corrects the sensitivity distribution data in such a manner that the pixel values of the pixels become closer to a normal value, wherein
after the sensitivity distribution data has been corrected, the unfolding processing unit performs the unfolding process again by using the sensitivity distribution data that has been corrected.
2. The magnetic resonance imaging apparatus according to claim 1 , wherein the correcting unit corrects the sensitivity distribution data in such a manner that a sensitivity difference between channels in a position of each of the pixels of which the pixel values have been judged to be abnormal becomes larger.
3. The magnetic resonance imaging apparatus according to claim 2 , wherein the judging unit calculates a representative value of pixel values, based on a distribution state of pixel values of pixels included in the unfolded image, and judges whether the unfolded image includes one or more pixels of which the pixel values are abnormal, based on the representative value that has been calculated.
4. The magnetic resonance imaging apparatus according to claim 3 , wherein the judging unit calculates a median as the representative value.
5. The magnetic resonance imaging apparatus according to claim 1 , wherein the judging unit calculates a representative value of pixel values, based on a distribution state of pixel values of pixels included in the unfolded image, and judges whether the unfolded image includes one or more pixels of which the pixel values are abnormal, based on the representative value that has been calculated.
6. The magnetic resonance imaging apparatus according to claim 5 , wherein the judging unit calculates a median as the representative value.
7. A magnetic resonance imaging apparatus comprising:
an executing unit that executes an image taking sequence according to a parallel imaging method so as to collect magnetic resonance signals by using a plurality of radio frequency coils;
a reconstructing unit that reconstructs a magnetic resonance image from the magnetic resonance signals;
an unfolding processing unit that performs an unfolding process so as to unfold aliasing that has occurred in the magnetic resonance image, by using sensitivity distribution data indicating a spatial sensitivity distribution of the radio frequency coils;
a judging unit that judges whether the unfolded image obtained as a result of the unfolding process includes one or more pixels of which pixel values are abnormal; and
a re-creating unit that, in a case where the judging unit has judged that the unfolded image includes one or more pixels of which the pixel values are abnormal, re-creates the sensitivity distribution data by causing the executing unit to execute a sensitivity measuring sequence so as to measure a spatial sensitivity distribution of the radio frequency coils, wherein
after the sensitivity distribution data has been re-created, the unfolding processing unit performs the unfolding process again by using the sensitivity distribution data that has been re-created.
8. The magnetic resonance imaging apparatus according to claim 7 , wherein the judging unit calculates a representative value of pixel values, based on a distribution state of pixel values of pixels included in the unfolded image, and judges whether the unfolded image includes one or more pixels of which the pixel values are abnormal, based on the representative value that has been calculated.
9. The magnetic resonance imaging apparatus according to claim 8 , wherein the judging unit calculates a median as the representative value.