Cardiac MRI Recent advances in equipment design and software has allowed for effective non-invasive, Magnetic Resonance Imaging of the heart and coronary arteries. The Cardiac MRI is not intended as a substitute for the Cardiac Angiography or Cardiac Catheterization but rather a screening tool for people who have a strong family history of heart disease and heart attacks. Cardiac MRI, CMRI, can be used to evaluate heart function by measuring the total output capacity. Clear pictures of the heart muscle, or myocardium, are created as the function data is collected. These pictures will show the thickness of the myocardium. Using the "cine" imaging technique, real time, or movie pictures show how the heart actually pumps blood. As the physician watches the cine movie they can access how the valves of the heart are functioning. |
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The Wall Motion imaging technique creates a visual grid overlay that "attaches" itself to the heart muscle helping the physician to see parts of the myocardium that may not be contracting. This information will enable the physician to make assumptions regarding the condition of the coronary artery that should carry blood to the part of the myocardium that is not pumping. If this assessment is made, another technique will allow for the visualization of the coronary arteries. The heart muscle receives its blood supply from two main arteries that stem from the portion of the aorta just beyond the valve that regulates the flow of fresh, oxygenated blood being pumped from the left ventricle of the heart. These arteries, the Right Coronary Artery, or RCA, and the Left Coronary Artery, or LCA, branch out to cover the surface of the heart. Cardiac MRI allows the imaging of these coronary arteries when there is ample blood flow within them. A healthy artery will be easily identified from its origin at the aorta through most of its course. When blood flow is hindered by some narrowing, the artery will be seen in segments. If the artery is significantly blocked, blood flow will not be detected and the artery will not be seen. This technique yields relatively reliable and accurate information provided that the patient is cooperative by maintaining rhythmic breathing and heart rate. |  |
Another technique, perfusion, requires an injection of a contrast called Gadolinium. After the injection of Gadolinium, rapid imaging of the myocardium yields images that show how blood is feeding, or perfusing the heart muscle. As the Gadolinium washes through the muscle, it will show areas that do not perfuse indicating an area of scar or injury. This scar or injury is generally caused by previous heart attacks, silent or otherwise. More importantly, with this technique, the physician can assess the viability of the muscle tissue as to the likelihood of revascularization from bypass surgery. Cardiac MRI will prove to be a valuable tool in the assessment of heart disease and coronary artery disease in patients who are at risk but currently asymptomatic. It is non-invasive in that it does not require the insertion of long probes and catheters. The patient will be comfortable throughout the procedure experiencing only the noise associated with MRI imaging that can be counteracted by the patient's choice of music or audio book. |  |
Unfortunately, not all patients are candidates for Cardiac MRI. Those with Pacemakers, Implanted infusion pumps, cerebral aneurysm clips, and some other implants may not have any type of MRI. All patients will be thoroughly screened for their protection prior to the Cardiac MRI. |
