What does Cardiac CT show?

In most cases cardiac CT is done to look for coronary artery disease or to make detailed measurements of other heart structures.

Coronary artery disease (Coronary CT Angiogram)

Coronary CT angiogram shows the inside of the coronary arteries and detects whether plaque (a buildup of cells, debris, calcium, and cholesterol within the artery) is present, where plaques are found, and how much blockage is caused by each plaque. 

Severe blockage in the right coronary artery on cardiac CT



3-dimensional view of normal coronary arteries

Coronary artery disease (Coronary Calcium CT)

Coronary calcium CT calculates a numerical score that summarizes the total amount of detected coronary artery calcium.  This score can be combined with the patient’s medical history to estimate risk of heart attack in the future.  In general:

  • Score of 0 indicates low risk
  • Score of 400 or higher indicates elevated risk


Other heart structures

When cardiac CT is done to evaluate other heart structures such as the aortic valve, left atrium, and heart pumping function, the reading physician will make specific measurements pertaining to these structures.

For example, for a cardiac CT done in preparation for ablation procedure to eliminate atrial fibrillation, the reading physician will calculate left atrial size and measure the connections between the pulmonary veins and the left atrium.  These measurements help the electrophysiologist (heart rhythm specialist) estimate the chance of ablation procedure success and design an individualized approach to performing the ablation procedure.