Cardiac Image Analysis

Cardiac image analysis is the study and diagnosis of disease based on cardiac imaging of the heart, which includes cardiac single photon emission computed tomography (SPECT), magnetic resonance imaging (MRI) and positron emission tomography (PET) scans. Thanks to the use of software, cardiac imaging analysis offers quick, automated measurements of the heart, and shows various medical conditions to the trained radiologist viewing the images. Cardiac imaging software allows radiologists the chance to isolate other features of the scan, to be sure of identification of features of the heart and anatomy of the chest. It can be used to help guide doctors inserting stents and repairing aneurysms.

Imaging the Heart

• There are various ways to image the function and structural aspects of the heart. Cardiac SPECT (single photon emission computed tomography) scans, also called myocardial perfusion imaging, are non-invasive tests that are used to assess the heart's structure and function.

  SPECT scans use small amounts of radioactive substances called isotopes. They are injected into a vein and can be traced through the blood stream. Special cameras are aimed at the heart, and as the isotopes pass through the heart, they allow the special cameras to produce detailed images of the heart and its arteries, valves and blood vessels. Doctors us the images obtained from the SPECT scan to assess blood flow to the heart muscle, and the way blood moves around the chambers of the heart. The images can help detect areas of decreased flow due to blockages in the arteries of the heart, usually caused by arterial calcification and plaque (from cholesterol, among other reasons). SPECT scans can also determine if someone has had a heart attack, since it can detect damage to the heart muscle. The degree of calcification and plaque detected can also help predict heart attack risk in patients suffering from heart disease symptoms.

  PET (positron emission tomography) is a type of nuclear imaging that evaluates heart function by examining how the blood is able to flow through the heart. It can see blockages and evaluate damage to heart tissue after a heart attack.

  MRI (magnetic resonance imaging) evaluates the structures and function of the heart, valves, major vessels and surrounding structures and can help diagnose and manage a variety of cardiovascular problems, such as coronary heart disease, valve disease and heart failure.

Visualizing Centerline References

• Cardiac imaging software creates a "centerline" view of any blood vessel, a 3-D image of the inside of the blood vessel, to show the cardiologist if there is any narrowing or blockage in that vessel. Not only can the software help identify blockage or stenosis (narrowing of the blood vessel), it can also calculate the lesion length and vessel diameter. Doctors use this information to plan whether or not a stent to re-open the blood vessel would be a good option for the patient.

Calcium Scoring

• Cardiac imaging can now show just how blocked arteries are by calcium and plaque. It can show if a blood vessel is an abnormal shape and help doctors determine whether or not to treat the blockage.

Evaluating Ejection Fraction

• Cardiac imaging shows the heart valves and their ejection fraction. The ejection fraction is the fraction of blood pumped out of ventricles with each heart beat. It is a measure of the efficiency of the heart muscle.

Identifying Other Structural Issues

• Cardiac imaging can also identify structural issues of the heart, such as atrial septal defect (ASD), a defect in the septum between the heart's two upper chambers (the atria), and aneurysms, an abnormal widening or ballooning of a portion of an artery due to weakness in the wall of the blood vessel. It can also help identify an abdominal aortic aneurysm (a potentially life-threatening widening of the major blood vessel in the abdomen), and the images can be used to repair it precisely.