Diffusion sensitizing imaging method, dynamic imaging method, and MRI apparatus

A diffusion sensitizing imaging method comprising the steps of:

• applying a slicing gradient which limits the exciting region in the slicing axis direction together with an exciting pulse;
• applying a diffusion sensitizing gradient;
• applying an FOV limiting gradient which limits the data collecting region in the phase encoding axis direction together with a reversing pulse;
• applying another diffusion sensitizing gradient;
• applying alternate positive and negative gradient magnetic field pulses continuously to image multiple echoes and collecting MR data from the resulting echoes;
• and
• producing a diffusion sensitized image of the data collecting region from the collected MR data, wherein
• the timing of the alternative posite and negative gradient magnetic field pulses are adjusted such that the resulting point in k-space corresponding to a spin echo center precedes the actual k-space center so that the resulting time interval from the time of application of the negative gradient magnetic field pulse to the time of commencement of application of the positive gradient magnetic field pulse is longer than the case of a resulting coincident point in k-space corresponding to the spin echo center and the actual k-space center, thereby extending the duration of the diffusion sensitizing gradients accordingly.

A method of dynamic imaging comprising the steps of:

• applying a slicing gradient which limits the exciting region in the slicing axis direction together with an exciting pulse;
• applying an FOV limiting gradient which limits the data collecting region in the phase encoding axis direction together with a reversing pulse;
• and
• applying and reversing a gradient magnetic field continuously to image multiple echoes and collecting MR data from the resulting echoes, wherein
• said foregoing steps are repeated at different times thereby to produce images of the same data collecting region from the MR data collected at the different times.

An MRI apparatus comprising:

• data collecting means which applies a slicing gradient which limits the exciting region in the slicing axis direction together with an exciting pulse, applies a diffusion sensitizing gradient, applies an FOV limiting gradient which limits the data collecting region in the phase encoding axis direction together with a reversing pulse, applies a diffusion sensitizing gradient, and reverses the gradient magnetic field continuously to image multiple echoes and collects MR data from the resulting echoes;
• image forming means which produces a diffusion sensitized image from the collected MR data;
• and
• image display means which displays the produced diffusion sensitized image.

An MRI apparatus comprising:

• data collecting means which applies a slicing gradient which limits the exciting region in the slicing axis direction together with an exciting pulse, applies a first diffusion sensitizing gradient, applies an FOV limiting gradient which limits the data collecting region in the phase encoding axis direction together with a reversing pulse, applies a second diffusion sensitizing gradient, and applies and reverses gradient magnetic fields continuously to image multiple echoes and collects MR data from the resulting echoes, with the timing of application of the reverse gradient magnetic field and the gradient magnetic field being adjusted such that the resulting point in k-space corresponding to a spin echo center precedes the actual k-space center so that the resulting time interval from the application of the reverse gradient magnetic field to the commencement of application of the gradent magnetic field is longer than the case of a resulting coincident point in k-space corresponding to the spin echo center and the actual k-space center, thereby extending the duration of the diffusion sensitizing gradients accordingly;
• image forming means which produces a diffusion sensitized image from the collected MR data;
• and
• image display means which displays the produced diffusion sensitized image.

An MRI apparatus comprising:

• data collecting means which applies a slicing gradient which limits the exciting region in the slicing axis direction together with an exciting pulse, applies an FOV limiting gradient which limits the data collecting region in the phase encoding axis direction together with a reversing pulse, and reverses the gradient magnetic field continuously to image multiple echoes and collects MR data from the resulting echoes, with the foregoing operations being repeated for different time periods;
• image forming means which produces images for the same data collecting region from MR data collected at different times;
• and
• image display means which displays the images obtained at the different time periods.