Two separate acquisitions (ECG-synchronized for the aortic root and non-gated for the aorta and peripheral vessels) may be preferable to an ECG-synchronized acquisition of the entire volume to reduce the amount of contrast agent.2 A total contrast dose of 45 ml is essential for ECG-synchronized CCTA that utilizes a 64-multislice CT scanner (MSCT) in order to obtain satisfactory image quality and SNR of the aortic root. Depending on the remaining amount of allowable contrast, a decision was then made to perform a non-gated CT of the aorta and peripheral vessels either with no contrast or a low-dose-contrast protocol that we have in place for selectively enhancing the ilio-femoral arterial regions.