It is a painless and non-invasive test that uses a strong magnetic field, radio waves and a computer to make highly detailed images of the brain, eyes, and surrounding areas. The test involves injecting a contrast media into a vein to improve the visibility of soft tissues like organs, muscles, tendons and blood vessels. The test helps detect loss of vision, abnormal bulging of the eyes, stroke, aneurysm, tumour, multiple sclerosis, hemorrhage and brain diseases like chronic headaches.