Scan Heart

What is a Scan of the Heart?
Heart scans are MRI or Computed Tomography (CT) scans that are specialized to look at the heart. Heart scans are usually performed using computed tomography because of better resolution (the ability to see small structures) and the ability to determine a calcium score.  A physician may request a cardiac MRI exam in certain situations, including the detection of scar tissue in myocardial infarct.

What are Scans of the Heart used for?
There are three main parts to a heart scan. A heart scan can be used to determine a "calcium score." A calcium score refers to the amount of calcium that has accumulated in the coronary arteries. This has been associated with coronary artery disease and an increased risk of myocardial infarction (heart attack) in the future.  Your physician may use your calcium score in conjunction with other risk factors (age, cholesterol levels, etc.) to determine if you are at a high risk for heart disease in the future.

Secondly, a heart scan can look at the overall structure of the heart, including the valves and chambers of the heart.  Enlarged chambers in the heart may signify heart disease.  A scan of the heart can also evaluate heart function.  By looking at changes in the size of the heart as it beats, your physician can determine how well your heart is pumping blood to the rest of the body.

Finally, modern heart scanners are capable of looking directly at the coronary arteries, a process also known as "CT Angiography."  In CT angiography, "contrast" material is inserted into a vein in the arm.  Contrast appears bright on a CT scan, and any areas that contain contrast will be enhanced on a CT scan.  As the contrast travels from the vein into the heart itself, the coronary arteries appear bright. 

The image above shows the evaluation of coronary arteries.  Areas of blockage will have minimal flow in the coronary vessel, and the contrast will not be visualized or appear narrowed.  If an area of blockage is seen, your physician may refer you to a cardiologist to perform a procedure to open up the blockage.  This can be completed through angioplasty, a procefure where a balloon is dilated inside the coronary artery to restore blood flow in the vessel.  Your physician may also insert a stent to ensure that this area stays open after the procedure is completed.  The stent is similar to a small metal cage that keeps the vessel open and allows blood to flow through the artery.