Determining the "best" scan for the heart depends entirely on what the doctor is trying to diagnose. The reference provided only mentions one type of scan.
A Cardiac CT scan (also known as a CAT scan) is a valuable, non-invasive imaging test that uses X-rays to create detailed pictures of your heart and blood vessels. These images are compiled to form a 3D model of your heart, as stated in the reference provided.
Therefore, if the physician needs a detailed 3D model of the heart and its blood vessels, a Cardiac CT scan might be deemed "best". However, other heart scans exist that are not mentioned in the provided reference.