What makes a coronary CT angiogram nondiagnostic?

Despite the high diagnostic accuracy of multidetector coronary computed tomographic angiography (CCTA) for the detection and exclusion of obstructive coronary artery stenosis, several technologic limitations of current generation CT scanners may cause artifacts that prevent interpretation of images or cause misclassification of lesions. This review discusses the identification and resolution of the most commonly encountered artifacts that may cause a CCTA to be nondiagnostic, including aspects related to (1) spatial resolution, (2) temporal resolution, (3) contrast enhancement, and (4) other patient-specific factors.