Final answer:
Changing the grid ratio from 5:1 to 12:1 in MRT without altering the technical factors will result in a decreased EI, as the higher grid ratio absorbs more scattered radiation, impacting image contrast.
Step-by-step explanation:
When the grid ratio of an MRT (Magnetic Resonance Technology) is changed from 5:1 to 12:1 without adjusting the technical factors, the resultant image will have a decreased EI (Exposure Index). This is because the higher grid ratio means more scattered radiation is absorbed, thus less reaches the image receptor. With fewer X-ray photons reaching the detector, the image's exposure index, which is a measure of the amount of radiation reaching the receptor, will decrease. This adjustment primarily affects the contrast of the resultant image rather than the spatial resolution. It is essential to adjust the exposure factors whenever changing the grid to maintain image quality.