What do I need to know for a heart MRI?

A magnetic resonance tomograph generates images of tissues and structures using a strong magnetic field. For this reason, no magnetic material whatsoever may be present in the room during the examination, since the switched-on device would immediately attract everything with great force. For safety reasons, an MRI examination cannot be used for some people.

These include people with pacemakers, implanted defibrillators, drug pumps (e.g. cancer patients) or ports (permanent access for drugs). All these things contain metals that could interact with the magnetic field and harm the person concerned. But also tattoos, which were engraved with lead-containing colors, are a contraindication for a cardio-MRI.

Before the examination, all piercings, watches and other jewelry must be removed from the body. Modern screws, plates or artificial hip joints are made of titanium or another metal that does not react magnetically and are therefore harmless during an MRI examination. During an MRI examination of the heart, instructions are usually given on how to breathe in or hold your breath.

In order to increase the significance of the images, these instructions should be followed very carefully.Modern screws, plates or artificial hip joints are made of titanium or another metal that does not react magnetically and are therefore harmless during an MRI examination. During an MRI examination of the heart, instructions are usually given on how to breathe in or hold your breath. In order to increase the significance of the images, these instructions should be followed very carefully.

When is an MRI of the heart performed (indication)?

There are a variety of heart disorders for which an MRI examination can help to identify the exact location or trigger of the symptoms. For example, after a heart attack (myocardial infarction), parts of the heart muscle no longer function properly because they are not supplied with blood. To find out how much of the heart muscle tissue is already no longer functioning and how much can still be saved by therapies such as bypass surgery, a cardio-MRI can be performed after a heart attack.

Changes and diseases of the coronary arteries, i.e. the vessels that supply the heart with blood, can also be depicted well with an MRI examination. For example, the MRI image of the heart can show bulges (aneurysms), inflammations or blood clots in the vessel wall. Calcium deposits, as they occur in arteriosclerosis, can be made poorly visible by the heart in the MRI.

However, the best method of imaging coronary arteries remains the use of a cardiac catheter in coronary angiography. The vessels around the heart become thinner and thinner over the course of time and at some point cannot be visualized by the MRI. However, the blood supply to the heart muscle through the coronary arteries can be well assessed during MRI, for example by administering a drug that causes stress to the heart.

In this way, it becomes clear which areas of the heart are sufficiently supplied under stress and which are not. Even after a bypass operation, an MRI examination of the heart can be useful to check the patency of the newly created vascular connections. There are a number of other indications for which a cardiac MRI can be performed. These include congenital heart defects, heart tumors, cardiac blood clots (thrombi), heart valve defects or diseases of the large vessels of the thorax.