Abstract: Described here are systems and methods for magnetic resonance imaging (“MRI”) using a sweeping frequency excitation applied during a time-varying magnetic field gradient. As an example, a gradient-modulated offset independent adiabaticity (“GOIA”) approach can be used to modify the pattern of the sweeping frequency excitation. Data are acquired as time domain signals and processed to generate images. As an example, the time domain signals are processed using a correlation between a Fourier transform of the gradient-modulated sweeping frequency excitation and a Fourier transform of the time domain signals.

Abstract: A method for acquiring magnetic resonance imaging data from a subject. The method includes performing a series of radio frequency pulses formed of individual RF pulses applied with a constant time interval between each of the individual RF pulses to form a consistent magnetic field about at least of a region of interest in the subject, where the RF pulse has a flip angle of less than 30 degrees. The method also includes performing phase encoding gradients to achieve spatial encoding and performing an imaging acquisition process over an acquisition window to acquire imaging data. The method further includes performing phase encoding rephasing gradients and repeating the preceding steps such that a time between a center of the acquisition window and a center of a first RF pulse in a first RF pulse in a repetition of the RF pulses is equal to the constant pulse interval.

Abstract: A method for acquiring magnetic resonance imaging data from a subject. The method includes performing a series of radio frequency pulses formed of individual RF pulses applied with a constant time interval between each of the individual RF pulses to form a consistent magnetic field about at least of a region of interest in the subject, where the RF pulse has a flip angle of less than 30 degrees. The method also includes performing phase encoding gradients to achieve spatial encoding and performing an imaging acquisition process over an acquisition window to acquire imaging data. The method further includes performing phase encoding rephasing gradients and repeating the preceding steps such that a time between a center of the acquisition window and a center of a first RF pulse in a first RF pulse in a repetition of the RF pulses is equal to the constant pulse interval.

Abstract: Systems and methods for pointwise encoding time reduction with radial acquisition (“PETRA”) magnetic resonance imaging (“MRI”) using a gradient modulation scheme to enable higher readout bandwidth while keeping the missing samples of the central region of k-space small are provided. This acquisition scheme allows independent selection of the excitation and readout bandwidths, which allows a higher readout bandwidth while keeping the required number of missing central k-space samples low. This flexibility in selecting the excitation and readout bandwidth settings can mitigate the peak radio frequency power and specific absorption rate limitations on flip angle in traditional PETRA imaging schemes.

Abstract: Systems and methods for pointwise encoding time reduction with radial acquisition (“PETRA”) magnetic resonance imaging (“MRI”) using a gradient modulation scheme to enable higher readout bandwidth while keeping the missing samples of the central region of k-space small are provided. This acquisition scheme allows independent selection of the excitation and readout bandwidths, which allows a higher readout bandwidth while keeping the required number of missing central k-space samples low. This flexibility in selecting the excitation and readout bandwidth settings can mitigate the peak radio frequency power and specific absorption rate limitations on flip angle in traditional PETRA imaging schemes.

Abstract: Described here are systems and methods for magnetic resonance imaging (“MRI”) using a sweeping frequency excitation applied during a time-varying magnetic field gradient. As an example, a gradient-modulated offset independent adiabaticity (“GOIA”) approach can be used to modify the pattern of the sweeping frequency excitation. Data are acquired as time domain signals and processed to generate images. As an example, the time domain signals are processed using a correlation between a Fourier transform of the gradient-modulated sweeping frequency excitation and a Fourier transform of the time domain signals.