Intraindividual comparison of photon-counting detector CT and third-generation dual-source energy-integrating detector CT in multiphasic contrast-enhanced abdominal CT

This study aimed to compare image quality between photon-counting detector computed tomography (PCD-CT) and third-generation dual-source energy-integrating detector CT (EID-CT) in multiphasic contrast-enhanced abdominal imaging using intraindividual analysis. This retrospective study included 88 patients who underwent both arterial phase (AP) and portal venous phase (PVP) abdominal CT with PCD-CT and EID-CT. Virtual monoenergetic images (VMIs) from 50 to 90 keV were reconstructed in PCD-CT, and 120 kVp images were applied in EID-CT. Quantitative image analysis evaluated CT attenuation, image noise, and contrast-to-noise ratio (CNR) in abdominal organs and vessels. Qualitative image quality, including vessel and parenchymal contrast, noise, and overall image quality, was assessed by two radiologists using a 5-point Likert scale. Compared with EID-CT, VMIs at 50–70 keV obtained from PCD-CT demonstrated significantly higher CT attenuation values (P < 0.001) across all evaluated abdominal organs and vessels. CNRs at 70 keV were significantly greater than those in EID-CT for all objects (P < 0.001), with increases of 13.3‒41.6% on AP and 40.4‒49.3% on PVP. Image noise in 70 keV VMI was lower than EID-CT (P < 0.001). Optimal image quality was achieved using VMIs at 60–70 keV, which achieved significantly higher qualitative scores (P < 0.001) than those from EID-CT. Substantial interobserver agreement was observed (κ = 0.60–0.79). The CT dose volume index was slightly lower with PCD-CT compared with EID-CT (P < 0.001), whereas dose-length product values remained similar. PCD-CT significantly improved image quality in multiphasic abdominal CT compared with third-generation dual-source EID-CT under equivalent radiation dose conditions. The superior iodine enhancement and higher CNR in VMIs at 60–70 keV highlight the advantages of PCD-CT.