Table 1.

Main coronary CT angiography artefacts causes and solutions

Artefacts	Problem	Cause	Solution
Blurring	Motion	–HR > acquisition speed –Respiration during acquisition –Inappropriate cardiac cycle phase reconstruction	–HR control (β- or calcium channel blockade, ivabradine) –Breath-hold instructions –Optimal cardiac cycle phase reconstruction –Use multisegment acquisition/reconstruction –Intelligent boundary detection
Stairstep or banding	–Motion –Cardiac cycle phase misregistration	–HR variation (tachycardia/arrhythmia) –ECG signal failure –Respiration during acquisition	–HR control (β- or calcium channel blockade, ivabradine) –Optimal cardiac cycle phase reconstruction –ECG editing –Pre-scan ECG quality check –Breath-hold instructions
Streak	Dark bands through objects adjacent to high-attenuation structures (beam-hardening effect)	–Metallic implants, surgical clips and coronary stents –Vessel filled with high iodine concentration	–Avoid undiluted contrast (use saline bolus flush) –Use a high-kilovoltage monoenegetic X-ray beam (dual-energy CT)
Blooming	High-attenuation objects appear larger than they are	–Coronary calcifications –Metallic implants, clips and coronary stents	–Use high spatial resolution reconstruction algorithms + iterative reconstruction (to decrease the noise) –Use the smallest available focal spot –Use a high kilovoltage monoenegetic X-ray beam (dual-energy CT)
Windmill	Highly attenuating structures are surrounded by low-attenuating rims, and low attenuating structures appear larger and have a “fan-like” appearance	–Moving structures during acquisition –HR > temporal resolution > spiral acquisition pitch	–Prefer sequential acquisition –HR control (β- or calcium channel blockade, ivabradine) –Optimize spiral scanning pitch
Low attenuating	Air bubbles	–Air within the contrast material bolus –Surgery	Check i.v. line before contrast injection

ECG, electrocardiogram; HR, heart rate.