Final answer:
MRI contrast is primarily influenced by the strength of the magnetic field and the use of contrast agents. Patient's age, room temperature, and time of day are not direct factors affecting MRI contrast. The physical condition and actions of the patient can impact MRI safety and image quality.
Step-by-step explanation:
The factors that influence contrast in magnetic resonance imaging (MRI) include variables such as the magnetic field strength and the use of contrast agents. High magnetic field strength requires higher frequency radio waves to resonate with the protons in the body, which affects the efficiency of the antenna used for broadcasting these waves. Additionally, variations in the magnetic field can be used to obtain position information and build up a map of tissue, with techniques like T1, T2, or proton density scans enhancing the contrast depending on different tissue relaxation times.
Factors such as the patient's age, room temperature, and time of day generally do not directly influence MRI contrast. However, the physical state of the patient, including movement or the presence of a pacemaker, can affect MRI safety and the quality of the imagery.