What is the impact of reduced phase encodings in a rectangular FOV?

When reduced phase encodings are used in a rectangular field of view (FOV), the most direct impact is a reduction in spatial resolution. This is because spatial resolution is determined by the number of phase encodings applied during image acquisition. When the number of phase encodings is reduced, the ability to distinguish between closely spaced structures diminishes, leading to a lower resolution image.

A rectangular FOV allows for optimization of imaging parameters, but decreasing the number of phase encodings effectively decreases the resolution in the phase encoding direction. This can result in images that appear less detailed or unclear, especially in regions where fine structural details are critical for diagnosis.

While changes in scan time or SNR may also occur, these factors are secondary to the direct impact on spatial resolution from reducing phase encodings. Reducing scan time could potentially increase throughput in a clinical setting but does not directly relate to the spatial resolution decline. Similarly, while SNR can be affected by various factors, the primary consequence of reduced phase encodings is indeed a reduction in spatial resolution.