Photon-counting detector CT reduces the rate of referrals to invasive coronary angiography as compared to CT with whole heart coverage energy-integrating detector

We sought to compare the degree of maximal stenosis and the rate of invasive coronary angiography (ICA) recommendations in patients who underwent coronary CT angiography (CCTA) with photon-counting detector CT (PCD-CT) versus those who underwent CCTA with whole heart coverage energy-integrating detector CT (EID-CT).In our retrospective single-center study, we included consecutive patients with suspected CAD who underwent CCTA performed with either PCD-CT or a 280-slice EID-CT. The degree of coronary stenosis was classified as no CAD, minimal (1-24 ​%), mild (25-49 ​%), moderate (50-69 ​%), severe stenosis (70-99 ​%), or occlusion.A total of 812 consecutive patients were included in the analysis, 401 patients scanned with EID-CT and 411 patients with PCD-CT (mean age: 58.4 ​± ​12.4 years, 45.4 ​% female). Despite the higher total coronary artery calcium score (CACS) in the PCD-CT group (10 [interquartile range (IQR) ​= ​0-152.8] vs 1 [IQR ​= ​0-94], p ​< ​0.001), obstructive CAD was more frequently reported in the EID-CT vs PCD-CT group (no CAD: 28.7 ​% vs 26.0 ​%, minimal: 23.2 ​% vs 30.9 ​%, mild: 19.7 ​% vs 23.4 ​%, moderate: 14.5 ​% vs 9.7 ​%, severe: 11.5 ​% vs 8.5 ​% and occlusion: 2.5 ​% vs 1.5 ​%, respectively, p ​= ​0.025). EID-CT was independently associated with downstream ICA (OR ​= ​2.76 [95%CI ​= ​1.58-4.97] p ​< ​0.001) in the overall patient population, in patients with CACS<400 (OR ​= ​2.18 [95%CI ​= ​1.13-4.39] p ​= ​0.024) and in patients with CACS≥400 (OR ​= ​3.83 [95%CI ​= ​1.42-11.05] p ​= ​0.010).In patients who underwent CCTA with PCD-CT the number of subsequent ICAs was lower as compared to patients who were scanned with EID-CT. This difference was greater in patients with extensive coronary calcification.