Photon-counting CT for hepato-bilio-pancreatic imaging: a qualitative head-to-head comparison with third-generation...

To compare qualitative reader-based image quality and anatomical detail of hepato-bilio-pancreatic structures between photon-counting detector CT (PCCT) and third-generation dual-source energy-integrating detector CT (EID-CT) in the same patient cohort.

This retrospective, single-center qualitative study included 25 patients who underwent contrast-enhanced abdominal CT with both PCCT (Siemens NAEOTOM Alpha pro) and EID-CT (Siemens SOMATOM Force) within a 3-month interval using comparable acquisition protocols, with the exception of reconstructed section thickness (0.4-0.6 mm for PCCT vs 1.0 mm for EID-CT). Four independent radiologists (two with > 10 years and two with < 5 years of experience) evaluated six parameters using a five-point Likert scale: overall image quality, arterial vascular visualization, venous vascular visualization, pancreatic ductal tree, biliary ductal tree, and peripancreatic lymph nodes. All readers were blinded to scanner type. Paired t-tests and non-parametric Wilcoxon signed-rank tests compared mean scores between PCCT and EID-CT. Inter-reader agreement was assessed using intraclass correlation coefficients. Statistical significance was set at p < 0.05. No quantitative image metrics or diagnostic performance outcomes were assessed; analyses were limited to reader-based Likert scale image quality scores.

PCCT demonstrated statistically significant superiority across all six parameters compared with EID-CT (overall image quality 4.82 vs 3.80, arterial vascular visualization 4.87 vs 3.98, venous vascular visualization 4.84 vs 3.91, pancreatic ductal tree 4.83 vs 3.51, biliary ductal tree 4.87 vs 3.63, peripancreatic lymph nodes 4.86 vs 3.81; all p < 0.0001). Mean score improvements with PCCT ranged from 0.89 to 1.32 points across all parameters. Inter-reader agreement was good to excellent for PCCT (ICC 0.70-0.92) and poor to moderate for EID-CT (ICC 0.43-0.70). Reader experience level did not significantly influence assessments (p = 0.94). These findings derive from a qualitative head-to-head comparison of image quality scores and were consistent across all four readers.

In this preliminary intra-patient comparison, photon-counting CT provided significantly superior image quality and anatomical detail in the hepato-bilio-pancreatic region compared to third-generation dual-source EID-CT. Enhanced visualization of ductal structures, distal vessels, and lymph nodes may support improved diagnostic confidence and more precise staging, although diagnostic performance was not assessed in this study. Because reconstructed section thickness differed between systems, these qualitative advantages cannot be attributed to detector technology alone and require confirmation in larger studies with matched protocols and diagnostic-accuracy endpoints.