Relaxation - Video Lesson

Welcome everyone to another lesson on MRI imaging principles. This video discusses the concept of relaxation in MRI image production and how technologists use relaxation techniques to affect image contrast. It is important to understand the concept of relaxation because of its relationship to image contrast. Contrast refers to the ability to differentiate between structures in an image. The inherent properties of different tissues in the body determine their brightness on the MRI image based on how quickly their hydrogen nuclei relax after an RF pulse. So let's look at relaxation. As you remember, when a patient is placed inside an MRI scanner, the useful hydrogen nuclei inside the patient align with the pole of the surrounding magnet. Then the technologist sends a radio frequency or RF pulse at the Larmor frequency.