Final answer:
In MRI technology, the x-gradient pulse creates positive and negative variations in the magnetic field along a sagittal plane to differentiate spatial locations of the MRI signal.
Step-by-step explanation:
When applying an x-gradient pulse, there are positive and negative variations in the magnetic field along a sagittal plane. In the context of magnetic resonance imaging (MRI), a gradient refers to a spatial variation in the magnetic field which is used to encode the position of spins within the body. Using a gradient along the x-axis, the magnetic field strength changes linearly in space, with one end of the gradient being higher (positive) and the other end lower (negative) than the central magnetic field strength. This gradient enables the spatial localization of the MRI signal and is essential for creating an image with two or three-dimensional information.