Magnetic resonance imaging, commonly known as MRI, is a technique that is used to create images of the underlying structure and functioning of the body. By using magnetic fields and radiofrequency fields, the technique causes the body to produce a rotating magnetic field that is detected by a scanning machine to produce an image. MRI scanning naturally offers better images with better contrast than most other scanning techniques, but if heightened contrast is needed for any reason, contrast agents are injected intravenously into the patient, to make it easier to view certain tissues, such as blood vessels and tumors. The mention of magnetic fields, radiofrequency fields, and contrast agents often gives people the impression that MRI is dangerous and has side effects, but in reality, MRI is quite harmless. MRI is in fact safer than other imaging techniques such as CT scanning, which uses ionizing radiation, which can be harmful. There are of course some safety precautions that need to be taken by doctors when performing an MRI, as with any other complex equipment that uses high energy and chemicals. However, as far as the patient is concerned, these mostly relate to the effect that the magnetic fields may have on pacemakers and metal implants in the body, or to specific disorders such as kidney failure or thermoregulation disorders that may react badly to the radio frequencies or the chemicals used as contrast agents.
It is quite unlikely that your headaches and twitching are directly caused by the MRI scan. They could be related to your other symptoms, due to which your doctor has recommended an MRI in the first place, or they could even be entirely unrelated and temporary. You should however consult the doctor who is treating you and/or the doctor who conducted the scan. Some high powered MRI techniques are capable of producing what is known as peripheral nerve stimulation (PNS), which involves a twitching sensation at one's extremities. This is unlikely to last very long, and also does not explain the headaches. In addition, most MRI systems do not use enough power as to cause peripheral nerve stimulation. However, it is of course advisable to check with your doctor or doctors.
If the headaches and twitching have nothing to do with the MRI, then they are most probably simply due to stress and lack of sleep. Lack of sufficient sleep sometimes causes twitching around the eyes, and headaches are also a common side effect of losing sleep over a long period of time. Make sure that you sleep enough for at least a week, and if the symptoms still persist, return to your doctor.
answered by G R