Phase and frequency

A matrix can be square or asymmetrical. A square matrix means that both phase and frequency values are equal. An asymmetrical matrix means that the phase axis is smaller than the frequency axis. Match the size and shape of the matrix, FOV, and Square Pixel, or Phase FOV options to resolve the anatomy being imaged.

When selecting a frequency matrix value, consider the following:

• Increase the frequency value and the minimum Time of Echo (TE) (echo space) value increases, the spatial resolution increases, the Signal-to-Noise Ratio (SNR) decreases, and the number of slices may decrease.
• Typically on an Echo Planar Imaging (EPI) single shot keep the frequency matrix as low as possible to keep the Echospace (ESP) as short as possible. Finding the right balance between ESP and resolution is critical.
• When selecting a phase matrix value, consider the following:
• Increase the phase value and the scan time increases (except for EPI scans), and the spatial resolution increases (except when Square Pixel is turned on).
• The phase value is smaller than or equal to the frequency value except for EPI.