Final answer:
During dynamic enhanced imaging, k-space is filled with data for visualizing contrast enhancement, with MRI contrast agents such as Gd³+ in a stable complex altering the magnetic properties of water in cells to provide detailed images.
Step-by-step explanation:
During dynamic enhanced imaging for vasculature or visceral structures, when contrast is administered, k-space is filled with data to ensure that the contrast enhancement is well visualized. MRI scans such as T1, T2, or proton density scans utilize different relaxation mechanisms of nuclei to tailor the image for specific clinical questions. Relaxation refers to the protons' return to equilibrium once the external magnetic field is turned off, a parameter that varies by tissue type and condition, like inflammation.
To enhance the contrast in images of soft tissues and structures like blood vessels, MRI contrast agents are crucial. These agents, often containing the metal ion Gd³+ within a complex such as DTPA³¯, alter the magnetic properties of water in cells, enhancing the differentiation of tissues in the resulting images. Gd³+ is highly paramagnetic due to its seven unpaired electrons, making it effective but also potentially toxic. Therefore, it is administered as a stable complex that does not dissociate within the body, allowing safe use and excretion.