This test uses a strong magnet to modify the atoms in the body for a tiny instant of time.  It does not use radiation and there are no known side-effects other than very rare kidney effects if a ‘dye’ called gadolinium is used if the kidney function is already significantly compromised.

It is used in  the following situations:

Uses of a cardiac magnetic resonance scan:

  1. To image the aorta as an alternative to CT scanning – particularly if it is advisable to avoid radiation.
  2. To look for evidence of abnormal texture in the left ventricle, e.g. scarring. This is a sign that the left ventricle is under strain.  It can also be done if your cardiologist suspects that there is heart muscle disease in addition to valve disease.  
  3. To check an increase in the volume of the heart as a sign of the need for surgery.  This is particularly used for the right ventricle if there is severe pulmonary regurgitation
  4. To assess congenital heart disease, for example looking for abnormalities in the pulmonary arteries (veins taking ‘blue’ blood from the heart to the lungs) beyond the pulmonary valve or for a narrowing in the aorta.
  5. Sometimes CMR can help with the grading of aortic valve regurgitation if there is doubt on the echocardiogram.  

A magnetic resonance scan usually takes about 40 minutes and is quite noisy.  It involves lying inside a magnetic tube which can cause a sense of claustrophobia.  The radiographer performing the scan will talk to you and have ways of making you more comfortable, for example by playing music through headphones.