Susceptibility phase imaging of deep gray matter: Presenting the effects of slice orientation.

Susceptibility-weighted image (SWI) is a T* gradient echo sequence, which is highly sensitive to substances that have magnetic properties. The phase and magnitude of SWI can play an important role in the diagnosis of several diseases. The phase data is highly affected by spatial variations in the main magnetic field of the magnetic resonance imaging (MRI) scanner.

Multiple sclerosis: validation of MR imaging for quantification and detection of iron.

Purpose: To investigate the relationship between iron staining and magnetic resonance (MR) imaging measurements in postmortem subjects with multiple sclerosis (MS).

Materials And Methods: Institutional ethical approval was obtained, and informed consent was obtained from the subjects and/or their families. Four MR imaging methods based on transverse relaxation (T2 weighting, R2 mapping, and R2* mapping) and phase imaging were performed by using a 4.

Susceptibility phase imaging with improved image contrast using moving window phase gradient fitting and minimal filtering.

Purpose: To enhance image contrast in susceptibility phase imaging using a new method of background phase removal.

Materials And Methods: A background phase removal method is proposed that uses the spatial gradient of the raw phase image to perform a moving window third-order local polynomial estimation and correction of the raw phase image followed by minimal high pass filtering. The method is demonstrated in simulation, 10 healthy volunteers, and 5 multiple sclerosis patients in comparison to a standard phase filtering approach.

Quantitative high-field imaging of sub-cortical gray matter in multiple sclerosis.

Background: In addition to neuronal injury, inflammatory, and demyelinating processes, evidence suggests multiple sclerosis (MS) is also associated with increased iron deposition in the basal ganglia. Magnetic resonance imaging (MRI), particularly at very high field strengths, is sensitive to iron accumulation and may enable visualization and quantification of iron associated with MS.

Objectives: To investigate the sub-cortical gray matter in patients with early-stage relapsing-remitting MS using multiple, and novel, quantitative MRI measures at very high field.

Three-dimensional MRI with independent slab excitation and encoding.

Three-dimensional MRI is typically performed with the same orientation for radiofrequency slab excitation and slab select phase encoding. We introduce independent slab excitation and encoding to create a new degree of freedom in three-dimensional MRI, which is the angular relationship between the prescribed excitation volume and the voxel encoding grid. By separating the directions of slab excitation and slab phase encoding, the independent slab excitation and encoding method allows choice of optimal voxel orientation, while maintaining volume excitation based on anatomic landmarks.

Detecting lesions in multiple sclerosis at 4.7 tesla using phase susceptibility-weighting and T2-weighting.

Purpose: To demonstrate 4.7 Tesla (T) imaging methods for visualizing lesions in multiple sclerosis in the human brain using phase susceptibility-weighting and T2 weighting.

Materials And Methods: Seven patients with relapsing-remitting multiple sclerosis were imaged at 4.

Effects of RF inhomogeneity at 3.0T on ramped RF excitation: application to 3D time-of-flight MR angiography of the intracranial arteries.

Purpose: To demonstrate the effects of inherent RF inhomogeneity on ramped RF excitation at 3.0T, and to introduce a simple correction for improving visualization of distal intracranial arteries in three-dimensional time-of-flight MR angiography (3D-TOF-MRA).

Materials And Methods: At 3.