How much calcium is too much calcium for coronary computerized tomographic angiography?

The coronary artery calcium (CAC) score above which it is recommended that coronary computerized tomographic angiography (CTA) not be performed has been steadily increasing. Currently, calcium scores > 1000 are thought to prohibit CTA accurate interpretation. However, a reasoned approach suggests that there is no absolute upper limit that applies to all patients and imaging centers. To anticipate the problems posed by calcium, a CAC scan must be obtained before CTA. Understanding the clinical goals of the CTA and the source and recognition of CAC-based imaging artifacts can enable accurate clinical CTA examinations even in the setting of high calcium scores.