MRI Under General Anaesthetic (GA)

An MRI under general anaesthetic is an MRI performed while you are fully asleep under the care of an anaesthetist. It is reserved for situations where neither being awake nor light sedation will allow a usable scan — for example very young children, people with severe learning disability or certain movement disorders, or anyone who genuinely cannot keep still enough for the images. It is used only when the information from the scan is important and no gentler option will work.

The scan uses the same magnet-and-radio-wave imaging as any MRI. What changes is that an anaesthetist gives medicines, usually through a vein, that send you into a controlled deep sleep so you are completely unaware and perfectly still. Your breathing is supported and your heart rate, oxygen and other vital signs are continuously monitored by the anaesthetic team throughout, using MRI-compatible equipment. Because the scanner's magnet is always on, all the anaesthetic equipment in the room is specially designed to be safe near it.

A general anaesthetic needs proper preparation. You will have a pre-assessment, be asked not to eat or drink for a set period beforehand, and meet the anaesthetist to discuss your health and any medicines. After the scan you wake up in a recovery area and are watched until you are alert and stable. You will need someone to take you home and stay with you, and you should not drive or make important decisions for the rest of the day. Full recovery of normal alertness usually takes the rest of that day.

For some patients, a general anaesthetic is the only way to obtain the detailed spinal images needed to diagnose and plan treatment. It guarantees complete stillness and therefore clear pictures. Because any anaesthetic carries its own small risks, it is used selectively, only when the diagnostic benefit clearly justifies it and lighter approaches are unsuitable — a judgement made together by the referring specialist and the anaesthetic team.

• —Royal College of Anaesthetists — Guidelines and Standards
• —Royal College of Radiologists — iRefer: Making the Best Use of Clinical Radiology
• —MHRA — Safety Guidelines for Magnetic Resonance Imaging Equipment in Clinical Use

This information is for general patient education and is not a substitute for an individual consultation. Always seek personalised advice from a qualified spinal specialist.