Cardiovascular MRI is a relatively new technique that provides a physician a unique way to look at the heart and blood vessels. The images are made with the use of a strong magnet and do not use radiation or iodine based contrast. MRI of the heart requires a special scanner and software. This scanner cannot be an “open magnet” because it must have the highest possible gradients. Fortunately, the inside size of the cardiac MRI machine is larger than the usual MRI machine.

1) Heart size and function

MRI gives the best images of the heart muscle of all non-invasive cardiac techniques. It is not limited by a person’s shape. Because of the excellent images, MRI is the most accurate way to measure the heart chamber size, wall thickness, and function. This accurate test makes follow-up tests highly reproducible. As a result, patients with severely leaking heart valves can be followed with serial tests to best determine when the valve may need replacement.

2) Assessment of the cause of heart muscle dysfunction (cardiomyopathy)

Heart muscle dysfunction can come from many different causes. MRI is uniquely able to measure the degree of heart function, the presence and extent of permanent heart damage from a heart attack, and the ability of the heart to recover its function if the arteries of the heart were to be opened (eg. Viability). MRI can determine if there is swelling of the heart muscle. This allows the physician to determine if a virus or heart attack has recently caused a problem in the heart. Thickened heart muscle may lead to serious heart rhythm problems. MRI can evaluate the degree of heart muscle scarring in patients with thickened hearts (eg. Hypertrophic cardiomyopathy) and presumably help predict the likelihood of the occurrence of these heart rhythms. Diseases that harm other organs can also effect the heart. Abnormalities seen with MRI can distinguish the effect of heart artery problems from those of systemic diseases.

3) Predict outcome after a heart attack

Following a heart attack, heart muscle often does not initially work in the area fed by the artery that caused the attack. A cardiac MRI can determine whether the non-working heart muscle is just stunned and can recover. It also can determine if microscopic small blood vessels in the heart attack area are blocked. This finding suggests that the damaged heart muscle is at high risk for causing further heart problems and requires aggressive medical treatment.

4) Coronary artery anomalies

Occasionally, people are born with their heart arteries coming from an unusual location. Some of these “anomalies” can cause chest pain in otherwise healthy people and may rarely lead to sudden death. Cardiac MRI can determine the presence and risk of these abnormalities with no risk to the patient from the test. It should be noted that the quality of the images of the heart arteries is not reliable enough to look at the arteries to evaluate blockages.

5) Aortic valve regurgitation

Cardiac MRI allows for the most accurate measurement of the degree of leakage of the aortic valve. There is a common association of enlargement of the aorta as well as leakage of the aortic valve. MRI also clearly views the aortic valve, its function, and the size of the aorta.

6) Aortic valve disease

Aortic enlargement, blockages, dissection, or fatty accumulation in the aortic wall can be viewed. Serial measurements are reproducible over time.

7) Pericardial disease

MRI clearly visualizes the thickness of the lining (pericardium) of the heart and helps physicians determine if surgery may be helpful. MRI also shows whether the lining is inflamed and a potential source of chest pain.

8) Perfusion

Although it has not been completely evaluated, the results of stress tests looking at blood flow appear similar to tests using nuclear medicine but offers other more accurate complimentary information.

9) Dangerous heart rhythms

Cardiac MRI can look very clearly at the right side of the heart. Certain hereditary problems involving the right side of the heart can lead to serious heart rhythms and can be diagnosed with MRI. Scarring in the left side of the heart can be the cause of heart rhythm problems and be diagnosed by MRI.

10) High blood pressure

MRI of the kidney arteries can identify a correctable cause of high blood pressure that occurs occasionally. Cardiac MRI also accurately measures whether there is thickening of the heart muscle from high blood pressure.

11) Congenital heart disease

MRI can accurately measure the shunting of blood flow from one side of the heart to the other side. It can clearly look at the result from prior heart surgery and evaluate the connections of the heart and arteries quite clearly.

12) Heart tumors and blood clots

The very clear view of the heart and the multiple MRI techniques available allow a physician to determine the presence, size, and extent of blood clots and tumors.

Patients cannot have a MRI if a pacemaker, implantable defibrillator, or brain aneurysm clip is present. Heart valves and artery stents are not problem for MRI.

Choose a link below for more information about MRI and other cardiac imaging trials in progress at the Minneapolis Heart Institute and Minneapolis Heart Institute Foundation.

Cardiac Imaging Research

Other tests for this sub-specialty

• Coronary CT Angiogram Scan
• Echocardiogram
• Exercise Stress Testing
• HeartScan (Electron Beam Coronary Calcium Scoring)
• MUGA Scan (Radionuclide Angiogram)
• Mycardial Perfusion Scan 
• Stress Echocardiogram
• Transesophageal Echocardiogram