A cardiac magnetic resonance imaging (MRI) stress test is used to view heart tissue and anatomy in two dimensions to determine whether the coronary arteries are stenotic under medication-induced stress. The MRI technique captures the signals emitted by hydrogen protons, which become aligned when the body is placed under a powerful magnetic field and when they are excited by radio frequencies.
60 to 90 minutes
Patients lie down on their backs throughout the exam. Electrodes are connected to a small device. An automatic injector is connected to the IV. An antenna that looks like a plate is placed on the chest.
The MRI machine looks somewhat like a tunnel open at both ends, and the body part that is being scanned has to be at the centre of the tunnel. A technologist gives patients instructions on when to hold their breath and communicates with them during the exam. Some patients may feel heat, which is a known effect of radio waves, but this is harmless.
In the middle of the exam, a medication will be injected to dilate the coronary vessels and activate heart function.
Again, the technologist will explain the effects and give instructions.
Generally, this period lasts 6 to 15 minutes depending on the type of medication used (chosen by the cardiologist on the day of the exam). If a contrast agent will be injected during the exam, the technologist will give instructions.