Patients must be able to meet the weight requirements of the scanner, have the ability to lay supine and motionless with arms raised above their shoulders, and follow simple breathing instructions.

Chronic Kidney disease (GFR <60) is a relative contraindication given the potential for contrast-induced nephropathy (CIN); the risk of CIN must be weighed against the potential benefits of the study. However, severe kidney disease (GFR <30, not on dialysis) is an absolute contraindication and an alternative testing strategy should be pursued. Previous anaphylaxis to iodinated contrast or an allergic reaction to iodinated contrast after premedication is an absolute contraindication.

Atrial fibrillation and frequent ectopy are relative contraindications to CCTA and mandate retrospective gating (acquisition of the entire cardiac cycle) if performed at all. Additionally, heart rates in excess of 70 BPM are usually associated with excessive cardiac motion and efforts to modulate pulse rate must be undertaken. In this regard, an inability to tolerate beta-blockers may be a relative contraindication.

In younger individuals, the risk of potential long-term radiation exposure must be weighed against the potential benefits of the study. Additionally, dense coronary calcification may limit the interpretation and utility of the study, however a specific coronary calcium (Agaston) score that excludes the use of CCTA has not been recommended in the Society of Cardiovascular Computed Tomography (SCCT) guidelines.

Cardiac CT imaging equipment must meet the minimal technical capabilities required for the scan indication and the patient’s underlying characteristics. According to the ACCF/SCCT/ACR/AHA/ASE/ASNC/NASCI/SCAI/SCMR Appropriate Use Criteria, cardiac CT generally requires a minimum of 64 multi-detector rows, gantry rotation time no greater than 420 ms, sub millimeter spatial resolution and cardiac imaging software capable of three-dimensional post processing with reconstructed axial data, multi-planar reconstructions, and maximum intensity projections. Additionally, tube potential adjustment must be available for radiation reduction techniques, such as reducing the voltage to 100 mV for non-obese patients. Ideally, prospectively triggered ECG scanning and iterative reconstruction should also be available for further radiation reduction.

Heart rate control is crucial for obtaining optimal images without significant artifact and therefore the patient should be given oral beta-blockers the night prior and the morning of the procedure. If the patient’s heart rate is still elevated (>65 BPM), the patient should be given an additional dose of IV beta-blocker or calcium channel blocker as needed. Patients should abstain from caffeine or nicotine for at least 12 hours prior to procedure for purposes of heart rate control.

Nephrotoxic drugs should be discontinued and the patient should be screened for contrast induced nephropathy risk factors (diabetes mellitus, chronic kidney disease, congestive heart failure, age >75…) with an accurate history and a serum creatinine obtained prior to the procedure. Pre-procedural oral and possibly IV hydration may be necessary based on the patient’s baseline serum creatinine. Patients with a history of an Iodine allergy or an allergic contrast reaction require premedication with corticosteroids and histamine antagonists.

Breath holds are performed during image acquisition and theoretically reduce cardiac motion as well as decrease intrathoracic pressure leading to maximum superior vena cava flow and contrast enhancement.

A coronary scan (CCTA) should begin at the level of the carina or mid-pulmonary artery and end 2 cm below the diaphragm unless the patient has bypass grafts, which would require starting above the arch. A calcium score is often obtained prior to coronary CT for prognosis and estimate of plaque burden, as well as to optimize CCTA image acquisition.

Nitroglycerin 0.4–0.8 mg sublingual should be administered prior to image acquisition to improve image quality by arterial vasodilatation. However, this should be avoided in patients with systolic blood pressures less than 100 mmHg, significant aortic stenosis or hypertrophic cardiomyopathy and patients who are using phosphodiesterase inhibitors.