Coronary CT angiography: Dose reduction strategies

Table 1 Dose reduction strategies and corresponding effectiveness in dose reduction in coronary computer tomography angiography

Techniques	Advantages	Pitfalls	Dose reduction
Tube current modulation: anatomy-based	Suitable for unsymmetrical body habitus	No apparent reduction in CCTA procedure due to homogeneity of the body thickness in the cardiac region	20%-60%1
Tube current modulation: ECG- controlled	Dedicated for cardiac imaging Modulates tube current output during systolic phase	Heart rate must be regular	30%-50%
Low tube voltage (kVp)	Image structure with high-atomic number becomes more prominent than that with low-atomic number	Beam hardening artifacts may occur May increase image noise which leads to suboptimal image quality	Up to 30%
High pitch value	Fast image acquisition Reduce motion artifacts	Patient heart rate must at < 65 bpm and regular Can only be performed on second generation of dual-source CT scanner	Up to 80%
Iterative reconstruction algorithms	Improve contrast-to-noise ratio and spatial resolution Reduce image noise	High computational cost	Up to 40%
Prospectively ECG- triggered CCTA	High sensitivity in the detection of CAD Tube current is only ‘on’ in a short period during diastolic phase	Limited number for cardiac reconstruction phases No cardiac functional analysis	Up to 83%

¹Applied to the abdominal-pelvic region. CT: Computed tomography; CCTA: Coronary CT angiography; CAD: Coronary artery disease; ECG: Electrocardiogram.