Musculoskeletal system: here, MRI is used to look at the spine - to assess joint disease and soft tissue tumours. There is clear contrast between grey and white matter parts of the brain and this makes MRI the best choice for many other conditions, including multiple sclerosis, stroke, Alzheimer's disease and epilepsy. Quite often you can listen to the radio through the headphones or bring a CD to listen to.Д«rain: MRI is the first-choice investigation for brain tumours, as it produces clearer images than computerised tomography (CT) and shows hard-to-reach areas of the brain. The scanner is noisy so you will be given some headphones or earplugs to protect your ears from the noise. However, you can talk to them, usually via an intercom, and you will be observed at all times on a monitor. The radiographer sits in the control room next to the scanner and observes through the window. This helps to give clearer pictures of certain tissues or organs being examined.

In some cases, an injection of a special contrast dye is given into the bloodstream via a vein on the arm. Some parts of the country have access to 'open' scan machines. If you have a fear of confined spaces (claustrophobia) you should discuss this with your doctor before you go for the scan. Where you lie is quite enclosed and some people may find this very unsettling. Small children may need a general anaesthetic to keep them still long enough for the pictures to be taken. It may be a little uncomfortable lying still on the couch for this time. The whole procedure can take 15-40 minutes. The computer creates a picture based on the radio signals emitted from the body.Д«y Jan Ainali (own work) via Wikimedia Commons. The receiving device transmits the signals to a computer.These signals are detected by a receiving device in the scanner.So, for example, softer tissues can be distinguished from harder tissues on the basis of the signals sent. Therefore, the signal emitted from different body tissues varies. The protons in different tissues of the body realign at different speeds. When the burst of radio waves stop, the protons realign back into place.The radio waves knock the protons from their position.

Then short bursts of radio waves are sent from the scanner into your body.(Normally the millions of protons all lie in random directions.) All the protons line up in parallel to the magnetic field, like tiny magnets. A strong magnetic field aligns particles called protons which are within the hydrogen atoms.Your body contains millions of hydrogen atoms.

How long does an mri of the brain take