Systems and methods for magnetic resonance imaging
Methods and apparatus for operating an MRI system is provided. The disclosure provides a diffusion-prepared driven-equilibrium preparation for an imaging volume and acquiring 3-dimensional k-space data from said prepared volume by a plurality of echoplanar readouts of stimulated echoes. An excitation radio-frequency signal and first and second inversion RF signals are provided to define a field-of-view (FOV).
1. A method for interleaved MR imaging, comprising:
performing a preparation sequence comprising:
providing an excitation radio-frequency (RF) signal;
immediately after said excitation RF signal, providing first and second inversion RF signals to define a field-of-view (FOV);
following the preparation sequence, performing an interleaved multi-slice acquisition of the FOV over a sequence of acquisition segments to acquire k-space data, wherein (i) each segment applies an imaging RF pulse to the FOV with a flip angle and (ii) the flip angle is increased over the sequence of the acquisition segments; and
reconstructing one or more images based on the k-space data.
2. The method of claim 1 , wherein said first and second inversion RF signals comprise first and second inversion RF pulses.
3. The method of claim 2 , wherein said first inversion RF pulse is applied immediately after said excitation RF signal.
4. The method of claim 2 , wherein said first and second inversion RF pulses are separated by a time approximately 5 ms or larger.
5. The method of claim 2 , wherein said first and second inversion RF pulses are separated by a time less than 5 ms.
6. The method of claim 2 , wherein said first and second inversion RF pulses are separated by a time more than 5 ms.
7. The method of claim 2 , further comprising providing slice-selective gradients that are selected such that magnetization within said FOV is preserved while magnetization external to said FOV is suppressed, thereby allowing magnetization in each of a plurality of slices to be maintained in its equilibrium state while exciting and imaging one or more others of said plurality of slices.
8. A system for interleaved magnetic resonance imaging (MRI), comprising:
an MRI scanner;
one or more computers configured to generate one or more instructions for:
performing a preparation sequence via the MRI scanner comprising:
providing an excitation radio-frequency (RF) signal;
immediately after said excitation RF signal, providing first and second inversion RF signals to define a field-of-view (FOV); and
following the preparation sequence, performing an interleaved multi-slice acquisition of the FOV via the MRI scanner over a sequence of acquisition segments to acquire k-space data, wherein (i) each segment applies an imaging RF pulse to the FOV with a flip angle and (ii) the flip angle is increased over the sequence of the acquisition segments; and
reconstructing one or more images based on the k-space data.
9. The system of claim 8 , wherein said first and second inversion RF signals comprise first and second inversion RF pulses.
10. The system of claim 9 , wherein said first inversion RF pulse is applied immediately after said excitation RF signal.
11. The system of claim 9 , wherein said first and second inversion RF pulses are separated by a time approximately 5 ms or larger.
12. The system of claim 9 , wherein said first and second inversion RF pulses are separated by a time less than 5 ms.
13. The system of claim 9 , wherein said first and second inversion RF pulses are separated by a time more than 5 ms.
14. The system of claim 9 , wherein said one or more instructions further includes an instruction for providing slice-selective gradients that are selected such that magnetization within said FOV is preserved while magnetization external to said FOV is suppressed, thereby allowing magnetization in each of a plurality of slices to be maintained in its equilibrium state while exciting and imaging one or more others of said plurality of slices.