Modern CT coronary angiography (CT) technology and acquisition technique demonstrate excellent specificity and sensitivity (both 96–99%) for assessment of coronary graft stenoses (>50%) and graft occlusions when compared to invasive angiography (IA). Due to the inherently more complex nature of invasive angiography there is a shift to utilize CT coronary angiography as first line diagnostic investigation in haemodynamically stable graft (CABG) patients. It is less known how the two tests compare in regard to radiation dose, contrast use and impact on renal function in real life.