Abstract: A method for correcting image inhomogeneity includes acquiring a non-normalized image and a reference image using receiver coils. A high-signal mask and a low-signal mask are created. Each pixel in the high-signal mask is set to a predetermined integer value if the reference image pixel at the same specific location has a value above a threshold value. Each pixel in the low-signal mask is set to the predetermined integer value if the reference image pixel at the same specific location has a value below or equal to the threshold value. A coil normalization map is created by smoothing the reference image with filters. Then, an iterative procedure is performed to update the coil normalization map using the high-signal mask and the low-signal mask. Following the iterative procedure, the non-normalized image is divided by the current coil normalization map to yield a normalized image.

Abstract: A method for correcting image inhomogeneity includes acquiring a non-normalized image and a reference image using receiver coils. A high-signal mask and a low-signal mask are created. Each pixel in the high-signal mask is set to a predetermined integer value if the reference image pixel at the same specific location has a value above a threshold value. Each pixel in the low-signal mask is set to the predetermined integer value if the reference image pixel at the same specific location has a value below or equal to the threshold value. A coil normalization map is created by smoothing the reference image with filters. Then, an iterative procedure is performed to update the coil normalization map using the high-signal mask and the low-signal mask. Following the iterative procedure, the non-normalized image is divided by the current coil normalization map to yield a normalized image.

Abstract: A magnetic resonance imaging system and method are provided for improved phase-sensitive magnetic resonance imaging of tissues affected by cardiovascular pulsatile motion. A magnetically-prepared image dataset and corresponding reference image dataset (for phase sensitivity) are obtained within the duration of a single cardiac cycle. The paired datasets can be single-shot or segmented datasets and a navigator sequence can optionally be provided with each paired dataset. The system and method take advantage of the shape symmetry of the cardiac cycle to acquire the paired dataset in a shorter time interval, thereby reducing misregistration artifacts. The magnetic preparation can include inversion recovery pulses, FIDDLE sequences, other magnetic preparation sequences, or combinations thereof. The reference dataset can be acquired at a lower resolution than the corresponding magnetically-prepared dataset without compromising image quality.

Abstract: Magnetic resonance imaging (MRI) acquisition and reconstruction techniques that invert MR signals of selected frequencies without the application of inversion RF pulses are disclosed. An example method comprises acquisition of at least one MR image representative dataset and an associated phase reference dataset, and classifies anatomical material into a first component representing anatomical material having a first range of resonance frequencies associated with a first range of phase differences between the MR image representative dataset and the reference image dataset and a second component representing anatomical material having a second range of resonance frequencies associated with a second range of phase differences between the MR image representative dataset and the reference image dataset. The method assigns different visual attributes to first and second components derived using phase differences between the MR image representative dataset and the reference image dataset and displays an image.

Abstract: A magnetic resonance imaging system and method are provided for improved phase-sensitive magnetic resonance imaging of tissues affected by cardiovascular pulsatile motion. A magnetically-prepared image dataset and corresponding reference image dataset (for phase sensitivity) are obtained within the duration of a single cardiac cycle. The paired datasets can be single-shot or segmented datasets and a navigator sequence can optionally be provided with each paired dataset. The system and method take advantage of the shape symmetry of the cardiac cycle to acquire the paired dataset in a shorter time interval, thereby reducing misregistration artifacts. The magnetic preparation can include inversion recovery pulses, FIDDLE sequences, other magnetic preparation sequences, or combinations thereof. The reference dataset can be acquired at a lower resolution than the corresponding magnetically-prepared dataset without compromising image quality.

Abstract: A virtual frequency selective inversion (VFSI) method receives at least one MR image representative dataset and an associated phase reference dataset, and classifies anatomical material into a first component representing anatomical material having a first range of resonance frequencies associated with a first range of phase differences between the MR image representative dataset and the associated phase reference image dataset, and a second component representing anatomical material having a second range of resonance frequencies associated with a second range of phase differences between the MR image representative dataset and the associated phase reference image dataset. The method assigns different visual attributes to first and second components derived using phase differences between the MR image representative dataset and the reference image dataset and displays an image.

Abstract: An MR system acquires, over multiple heart cycles, image datasets representing multiple image slices of an anatomical region of interest of a patient. In the device, an RF signal generator and a magnetic field gradient generator provides an RF pulse and magnetic field gradient sequence for RF signal excitation of the region of interest and for acquiring RF data following the signal excitation. The sequence comprises, a first sequence occurring substantially immediately after the acquisition of image data using a readout magnetic field gradient. The first sequence includes an RF pulse with a predetermined flip angle followed by a magnetic field gradient pulse for reducing field magnetization to substantially zero. The first sequence is preceded by a dummy acquisition sequence comprising the elements of the first sequence except substantially without acquisition of data.

Abstract: An MR imaging system independently manipulates a fat and a water component of MR signals used for generating image data. An RF signal generator and a magnetic field gradient generator provide an RF pulse and magnetic field gradient sequence for acquisition of an MR signal discriminating between anatomical objects based on longitudinal relaxation time (T1). The sequence comprises, a first pulse sequence for selectively inverting a water component of the MR signal substantially exclusively of fat, a first time delay adjustable to discriminate between different anatomical elements, a second pulse sequence having a resonant frequency selected to invert a fat component of the MR signal substantially exclusively of water and a data acquisition magnetic field gradient for acquisition of the MR signal. An image shows enhanced visualization of discriminated anatomical elements.

Abstract: Magnetic resonance imaging (MRI) acquisition and reconstruction techniques that invert MR signals of selected frequencies without the application of inversion RF pulses are disclosed. An example method comprises acquisition of at least one MR image representative dataset and an associated phase reference dataset, and classifies anatomical material into a first component representing anatomical material having a first range of resonance frequencies associated with a first range of phase differences between the MR image representative dataset and the reference image dataset and a second component representing anatomical material having a second range of resonance frequencies associated with a second range of phase differences between the MR image representative dataset and the reference image dataset. The method assigns different visual attributes to first and second components derived using phase differences between the MR image representative dataset and the reference image dataset and displays an image.

Abstract: A virtual frequency selective inversion (VFSI) method receives at least one MR image representative dataset and an associated phase reference dataset, and classifies anatomical material into a first component representing anatomical material having a first range of resonance frequencies associated with a first range of phase differences between the MR image representative dataset and the associated phase reference image dataset, and a second component representing anatomical material having a second range of resonance frequencies associated with a second range of phase differences between the MR image representative dataset and the associated phase reference image dataset. The method assigns different visual attributes to first and second components derived using phase differences between the MR image representative dataset and the reference image dataset and displays an image.

Abstract: An MR system acquires, over multiple heart cycles, image datasets representing multiple image slices of an anatomical region of interest of a patient. In the device, an RF signal generator and a magnetic field gradient generator provides an RF pulse and magnetic field gradient sequence for RF signal excitation of the region of interest and for acquiring RF data following the signal excitation. The sequence comprises, a first sequence occurring substantially immediately after the acquisition of image data using a readout magnetic field gradient. The first sequence includes an RF pulse with a predetermined flip angle followed by a magnetic field gradient pulse for reducing field magnetization to substantially zero. The first sequence is preceded by a dummy acquisition sequence comprising the elements of the first sequence except substantially without acquisition of data.

Abstract: An MR imaging system independently manipulates a fat and a water component of MR signals used for generating image data. An RF signal generator and a magnetic field gradient generator provide an RF pulse and magnetic field gradient sequence for acquisition of an MR signal discriminating between anatomical objects based on longitudinal relaxation time (T1). The sequence comprises, a first pulse sequence for selectively inverting a water component of the MR signal substantially exclusively of fat, a first time delay adjustable to discriminate between different anatomical elements, a second pulse sequence having a resonant frequency selected to invert a fat component of the MR signal substantially exclusively of water and a data acquisition magnetic field gradient for acquisition of the MR signal. An image shows enhanced visualization of discriminated anatomical elements.