What is the phase matrix in MRI?

What is the phase matrix in MRI?

The matrix size is the number of frequency encoding steps, in one direction; and the number of phase encoding steps, in the other direction of the image plane. Assuming everything else is constant, increasing the number of frequency encodings or the number of phase steps results in improved resolution.

What is the difference between resolution and matrix?

Basic resolution is the number of pixels in the readout direction. Basic resolution also determines the size of the image matrix. Basic resolution is inversely proposal to the size of the pixel and (the lower the resolution the higher the pixel size).

What is FOV phase in MRI?

Field-of-view (FOV) refers the distance (in cm or mm) over which an MR image is acquired or displayed. The FOV is typically divided into several hundred picture elements (pixels), each approximately 1 mm² in size.

How is spatial resolution measured in MRI?

In MRI, spatial resolution is defined by the size of the imaging voxels. Since voxels are three-dimensional rectangular solids, the resolution is frequently different in the three different directions. The size of the voxel and therefore the resolution depends on matrix size, the field-of-view, and the slice thickness.

What is phase and frequency MRI?

Spatial encoding in MRI The second step of spatial localization is called phase encoding. A magnetic gradient field is applied briefly in one direction. As the change in frequency is very brief, when the gradient is switched off, it causes a change in phase that is proportional to the distance.

What is the difference between phase encoding and frequency encoding in MRI?

The frequency-encoding direction is along the x-axis in K-space (may or may not be that axis in the image, if it is rotated); this represents the time samples of the signal. The y-axis is the phase-encoding direction: each phase-encoding step yields a separate horizontal line.

How many pixels are in a matrix?

The typical number of pixels in a matrix ranges from about 512 × 512 to 1024 × 1024 and can be as large as 2500 × 2500.

What is FOV phase?

(FOV) Defined as the size of the two or three dimensional spatial encoding area of the image. Usually defined in units of mm².

What is TE and TR?

Repetition Time (TR) is the amount of time between successive pulse sequences applied to the same slice. Time to Echo (TE) is the time between the delivery of the RF pulse and the receipt of the echo signal. Tissue can be characterized by two different relaxation times – T1 and T2.

What is the difference between spatial and contrast resolution?

Spatial resolution is the ability to image small objects that have high subject contrast. Resolution is an imaging system’s ability to distinguish object detail.

What are phase encoding steps MRI?