How does the scan time change with an increase in phase matrix?

When the phase matrix is increased, the amount of data collected during an MRI scan also increases, which leads to a longer scan time. The phase matrix refers to the number of phase-encoding steps in the acquisition of the image. With a higher phase matrix, the system must sample more points in the frequency-encoding space to achieve increased spatial resolution. This involves additional time to obtain the required signal samples, resulting in an increase in the overall scan time.

By contrast, a lower phase matrix results in fewer phase-encoding steps, which can reduce scan time but at the potential cost of image resolution and detail. Therefore, as the phase matrix increases, it is essential to anticipate a corresponding increase in scan time to accommodate the additional data collection needed for the higher resolution images.