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

Background: 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). Methods: 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. Results: 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). Conclusion: 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.