1. A method for imaging a desired coronary artery or desired portion thereof utilizing a computed tomography (CT) imaging system comprising a rotating gantry, a detector array on the rotating gantry, and a radiation source on the rotating gantry configured to project a beam of radiation towards the detector array through a patient's heart; said method comprising: scanning a volume of the patient's heart with the CT imaging system to acquire projection data, the volume including at least a first desired coronary artery branch segment and a second desired coronary artery branch segment, and the acquired projection data including a first projection dataset representing the first desired coronary artery branch segment acquired during a first desired cardiac phase of a plurality of cardiac cycles of the patient and a second projection dataset representing the second desired coronary artery branch segment acquired during a second desired cardiac phase of a plurality of cardiac cycles of the patient; selecting the first cardiac phase corresponding to a low motion period of the first desired coronary artery branch segment of a patient's heart and selecting the second cardiac phase corresponding to a low motion period of the second desired coronary artery branch segment of a patient's heart; reconstructing a first 2D image of the first desired coronary artery branch segment utilizing the first projection dataset acquired during the first desired cardiac phase of a plurality of cardiac cycles to reduce motion artifacts of the first desired coronary artery branch segment; reconstructing a second 2D image of the second desired coronary artery branch segment utilizing the second projection dataset acquired during the second desired cardiac phase of a plurality of cardiac cycles to reduce motion artifacts of the second desired coronary artery branch segment; reconstructing at least one 3D image of the coronary artery utilizing the first 2D image and the second 2D image.