Final answer:
Gradient echo sequence used in fast, breath-hold dynamic contrast-enhanced imaging of the abdomen leverages rapid sequence imaging and is based on different relaxation mechanisms of nuclei like T1 and T2, important for capturing quick and quality images.
Step-by-step explanation:
When a gradient echo sequence is selected for fast, breath hold dynamic contrast-enhanced imaging of the abdomen, rapid sequence imaging is utilized. This method is particularly useful for capturing high-quality images quickly, which is essential when imaging dynamic processes such as the distribution of contrast material. Scans like T1, T2, or proton density rely on different relaxation mechanisms of nuclei, where relaxation is the time it takes for protons to return to equilibrium after being excited by an external magnetic field.