Final answer:
MRI uses a magnetic field and sometimes an MRI contrast agent to obtain detailed images of soft tissues, while IVP uses ionizing radiation and a contrast dye to image the urinary system. Patients with pacemakers cannot undergo MRI due to potential interference with the device.
Step-by-step explanation:
The statement regarding MRI (Magnetic Resonance Imaging) and IVP (Intravenous Pyelogram) tests is that MRI uses a magnetic field to obtain detailed images of soft tissues, while IVP is typically associated with the use of ionizing radiation to look at the urinary system.
During an MRI, a patient is placed within a solenoid that generates a large magnetic field, which changes the spin of protons primarily in the hydrogen atoms of water molecules within the body. This change in spin allows the MRI machine to create detailed images of soft tissues. Furthermore, to enhance the contrast in the images, a patient may be injected with an MRI contrast agent, often containing the metal ion Gd³+, which is highly paramagnetic and provides better differentiation of tissues.
On the other hand, IVP involves the injection of a contrast dye into the veins, which is then imaged using X-ray technology to assess the structure and function of the kidneys, ureters, and bladder. This method utilizes ionizing radiation, in contrast to MRI, which does not.