Method and magnetic resonance apparatus for echo planar imaging with data entry into k-space along a zigzag trajectory

A method for echo planar magnetic resonance (MR) imaging, comprising:

• operating an MR data acquisition unit, in which a subject is situated, to acquire MR raw data from the subject in an echo planar MR imaging sequence including, in said echo planar MR imaging sequence, radiating a radio-frequency (RF) pulse that produces a transverse magnetization of nuclear spins in the subject, said transverse magnetization of said nuclear spins exhibiting a phase;
• operating said MR data acquisition unit in said echo planar MR imaging sequence to also apply a sequence of readout gradient fields configured with alternating positive and negative values, and to apply a sequence of phase encoding gradient fields configured to have only positive values that continuously increase the phase of the transverse magnetization as a function of time, or to have only negative values that continuously decrease the phase of the transverse magnetization as a function of time, wherein applying said sequence of readout gradient fields and applying said sequence of phase encoding gradient fields produces a zigzag-type trajectory for entering MR raw data into an electronic memory organized as k-space;
• operating said MR data acquisition unit in said echo planar MR imaging sequence to acquire said MR raw data, via multiple receiver coils of said MR data acquisition unit, representing gradient echoes resulting from said transverse magnetization, while applying said sequence of readout gradient fields and said sequence of phase encoding gradient fields, and entering the acquired MR raw data into k-space along said zigzag-type trajectory, said zigzag-type trajectory in k-space exhibiting a first class of flanks that have positive values of said readout gradient fields and a second class of flanks that have negative values of the readout gradient fields;
• and
• from a processor, accessing said MR raw data in said electronic memory and applying a parallel MR image reconstruction algorithm to said MR raw data to obtain a data file representing an MR image of the subject, and making said data file available at an output of the processor in electronic form.

A magnetic resonance (MR) apparatus, comprising:

• an MR data acquisition unit comprising at least one radio-frequency (RF) transmission coil, a gradient system, and at least one RF reception coil;
• a control unit configured to operate the MR data acquisition unit, while a subject is situated therein, to acquire MR raw data from the subject in an echo planar MR imaging sequence including, in said echo planar MR imaging sequence, radiating from at least one RF pulse transmission coil that produces a transverse magnetization of nuclear spins in the subject, said transverse magnetization of said nuclear spins exhibiting a phase;
• said control unit being configured to operate said MR data acquisition unit in said echo planar MR imaging sequence to also apply, from said gradient system, a sequence of readout gradient fields configured with alternating positive and negative values, and to apply a sequence of phase encoding gradient fields configured to have only positive values that vary as a function of time to continuously increase the phase of the transverse magnetization as a function of time, or to have only negative values that vary as a function of time to continuously decrease the phase of the transverse magnetization as a function of time, wherein applying said sequence of readout gradient fields and applying said sequence of phase encoding gradient fields produces a zigzag-type trajectory for entering MR raw data into an electronic memory organized as k-space;
• said control unit being configured to operate said MR data acquisition unit in said echo planar MR imaging sequence to acquire, with said at least one RF reception coil, said MR raw data representing gradient echoes resulting from said transverse magnetization, while applying said sequence of readout gradient fields and said sequence of phase encoding gradient fields, and entering the acquired MR raw data into k-space along said zigzag-type trajectory;
• and
• a processor configured to access to said memory and make the MR raw data in k-space available in electronic form as a data file.

A magnetic resonance (MR) apparatus, comprising:

• an MR data acquisition unit comprising at least one radio-frequency (RF) transmission coil, a gradient system, and multiple RF reception coils;
• a control unit being configured to operate the MR data acquisition unit, while a subject is situated therein, to acquire MR raw data from the subject in an echo planar MR imaging sequence including, in said echo planar MR imaging sequence, radiating an RF pulse from said at least one RF transmission coil that produces a transverse magnetization of nuclear spins in the subject, said transverse magnetization of said nuclear spins exhibiting a phase;
• said control unit being configured to operate said MR data acquisition unit in said echo planar MR imaging sequence to also apply, from said gradient system, a sequence of readout gradient fields configured with alternating positive and negative values, and to apply a sequence of phase encoding gradient fields configured to have only positive values that continuously increase the phase of the transverse magnetization as a function of time, or to have only negative values that continuously decrease the phase of the transverse magnetization as a function of time, wherein applying said sequence of readout gradient fields and applying said sequence of phase encoding gradient fields produces a zigzag-type trajectory for entering MR raw data into an electronic memory organized as k-space;
• said control unit being configured to operate said MR data acquisition unit in said echo planar MR imaging sequence to acquire said MR raw data, via said multiple receiver coils of said MR data acquisition unit, representing gradient echoes resulting from said transverse magnetization, while applying said sequence of readout gradient fields and said sequence of phase encoding gradient fields, and entering the acquired MR raw data into k-space along said zigzag-type trajectory, said zigzag-type trajectory in k-space exhibiting a first class of flanks that have positive values of said readout gradient fields and a second class of flanks that have negative values of the readout gradient fields;
• and
• a processor configured to access said MR raw data in said electronic memory and apply a parallel MR image reconstruction algorithm to said MR raw data to obtain a data file representing an MR image of the subject, and to make said data file available at an output of the processor in electronic form.