Magnetic resonance imaging apparatus
A magnetic resonance imaging apparatus performs myocardial perfusion imaging of an object. An imaging unit acquires image data by imaging a heart of the object in synchronism with a biological signal from the object. An image generating unit generates an image concerning the heart of the object based on the image data. The imaging unit applies a probe pulse for detecting body motion of the object before imaging of the heart, and applies a spatial non-selective saturation pulse before application of the probe pulse, and a local selective pulse for flipping back a flip angle of the spatial non-selective saturation pulse with regard to a region to which the probe pulse is applied.
1. A magnetic resonance imaging (MRI) apparatus, comprising:
an MRI control system, connected to control gantry components, including at least one RF transmitter, at least one RF receiver and computer control circuits configured to effect specified MRI data acquisition sequences of RF and gradient magnetic pulses which acquire, from an object located within an imaging volume, RF nuclear magnetic resonance (NMR) spin responses emanating from different spatially located volumes of MRI nuclei respectively corresponding to different positions in k-space as a function of a magnetic field experienced by the nuclei;
said computer control circuits being configured to effect:
acquisition of MR image data from a predetermined region of an object by using a labeling pulse to generate contrast in the image data between different tissues and an RF pulse synchronized with a biological signal of the object which periodically fluctuates;
acquisition of a pattern of the biological signal of the object concurrent with execution of MRI data acquisition sequences;
dynamic real time adjustment of at least one image acquisition sequence condition parameter being used in said data acquisition sequences in response to a temporal change in the pattern of the biological signal; and
generation of an image of tissues in the predetermined region using the acquired image data which includes tissue contrast generated by the labeling pulse.
2. The magnetic resonance imaging apparatus of claim 1 , wherein a spatial nonselective pulse is used as the labeling pulse.
3. The magnetic resonance imaging apparatus of claim 1 , wherein a spatial selective pulse is used as the labeling pulse.
4. The magnetic resonance imaging apparatus of claim 1 , wherein a spatial selective pulse of each of a plurality of regions to be labeled is used as the labeling pulse.
5. The magnetic resonance imaging apparatus of claim 1 , wherein a period between an application time of the labeling pulse and a first application time of the RF pulse is dynamically adjusted.
6. The magnetic resonance imaging apparatus of claim 1 , wherein a flip angle of the labeling pulse is dynamically adjusted.
7. The magnetic resonance imaging apparatus of claim 1 , wherein a flip angle of the RF pulse is dynamically adjusted.
8. The magnetic resonance imaging apparatus of claim 1 , wherein whether to perform the image acquisition in synchronism with a next biological signal is determined in accordance with a time required for current image acquisition and timing of the next biological signal estimated based on the temporal change in the patterns of the biological signal.
9. The magnetic resonance imaging apparatus of claim 8 , wherein when it is determined that the image acquisition should be performed in synchronism with the next biological signal, the at least one image acquisition sequence condition parameter value is dynamically adjusted to be, at least one of a period between an application time of the labeling pulse and a first application time of the RF pulse, a flip angle of the labeling pulse, and a flip angle of the RF pulse.
10. The magnetic resonance imaging apparatus of claim 8 , wherein when it is determined that the image acquisition should not be performed in synchronism with the next biological signal, subsequent image acquisition is performed in synchronism with a biological signal after one cycle.
11. The magnetic resonance imaging apparatus of claim 1 , wherein whether to reject image data acquired in synchronism with a next biological signal is determined in accordance with a time required for current image data acquisition and timing of the next biological signal estimated based on the temporal change in the patterns of the biological signal.
12. The magnetic resonance imaging apparatus of claim 11 , wherein when it is determined that the image data acquired in synchronism with the next biological signal should be rejected, the image acquisition condition is controlled to perform image data acquisition using a same encode pattern as an encode pattern used for the rejected image data.
13. The magnetic resonance imaging apparatus of claim 1 , wherein the biological signal has a respiratory synchronization waveform, and when a cycle of the pattern of the biological signal is shorter than a predetermined cycle, the control unit controls at least a flip angle of the labeling pulse within a range of 90°≦α≦180°.
14. The magnetic resonance imaging apparatus of claim 1 , wherein the biological signal has a respiratory synchronization waveform.
15. The magnetic resonance imaging apparatus of claim 1 , wherein the biological signal has an ECG waveform or a pulse waveform.
16. The magnetic resonance imaging apparatus of claim 1 , wherein the temporal change in the patterns of the biological signal is temporal change in an interval of the biological signal.
17. The magnetic resonance imaging apparatus of claim 1 , wherein the temporal change in the patterns of the biological signal is temporal change in a period of the biological signal.
18. The magnetic resonance imaging apparatus of claim 1 , wherein the temporal change in the patterns of the biological signal is temporal change in wavelength of the biological signal.