{
  "abstract": "Background Metal blooming and partial-volume artifacts frequently limit conventional CT evaluation of coronary stents. Photon-counting CT (PCCT), through its ultra-high spatial resolution, has the potential to overcome these barriers and improve routine diagnostic assessment.Methods We retrospectively reviewed data from patients with prior coronary stenting who underwent routine, clinically indicated cardiac CT using conventional CT or PCCT over 12 months (March 2025–February 2026). The primary endpoint was stent-level non-interpretability. Secondary endpoints included patient-level non-interpretability and downstream testing. Statistics included Wilcoxon rank-sum, Fisher’s exact tests, and an adjusted binomial regression for stent-level non-interpretability incorporating scanner type, stent/vessel burden, distal involvement, age, and heart rate.Results Fifty-seven patients were included (20 conventional CT; 37 PCCT). Baseline characteristics including age, BMI, heart rate, and stent/vessel burden were similar between groups. Unadjusted stent-level non-interpretability was significantly lower with PCCT (10.5% [10/95] vs 25.5% [12/47]; p=0.04). Patient-level non-interpretability (10.8% [4/37] vs 25.0% [5/20]; p=0.25) and downstream testing (8.1% [3/37] vs 20.0% [4/20]; p=0.23) were numerically lower but non-significant. On adjusted analysis, lower odds of stent non-interpretability with PCCT were not statistically significant (OR 0.42, 95% CI 0.13–1.32; p=0.13). Notably, median DLP was significantly higher with PCCT (382 vs 161 mGy*cm; p<0.001) (table 1, figure 1).Conclusion PCCT was associated with lower unadjusted coronary stent non-interpretability than conventional CT, enhancing diagnostic yield. However, the associated higher radiation dose necessitates protocol optimization and larger prospective validation to establish definitive clinical utility. Which statement best summarises the findings of this retrospective study comparing conventional CT with photon-counting CT (PCCT) for coronary stent assessment?A. PCCT significantly reduced stent-level non-interpretability, patient-level non-interpretability, and downstream testing, without any increase in radiation dose.B. PCCT showed no difference from conventional CT for stent interpretability, but required fewer images and lower DLP.C. PCCT was associated with lower unadjusted stent-level non-interpretability than conventional CT, while patient-level non-interpretability and downstream testing were numerically lower but not statistically significant; DLP was higher with PCCT.D. Conventional CT outperformed PCCT for coronary stent assessment after adjustment for stent burden and distal involvement.E. PCCT reduced downstream testing only, with no difference in stent-level interpretability.Abstract 37 Table 1Baseline characteristics and clinical utility outcomes with conventional CT and photon-counting CT for coronary stent assessmentVariableConventional CTPCCTp_valuePatients, n2037Age, years63.5 (56, 73.25)65 (62, 76)0.39Male sex15/20 (75%)29/37 (78.38%)0.75BMI, kg/m227.47 (22.55, 29.42)25.14 (23.94, 28.44)0.72Heart rate, bpm67.5 (59.25, 75)63 (58, 70)0.31Beta blocker6/19 (31.58%)17/36 (47.22%)0.39GTN13/19 (68.42%)26/36 (72.22%)0.77Non-sinus rhythm0/20 (0%)2/37 (5.41%)0.54DLP160.5 (65.5, 286.5)382 (225, 582)0Number of images1890 (1316, 2754)4934 (4345, 6513)<0.001Number of stents1 (1, 3)2 (1, 3)0.26Number of vessels1 (1, 2)1 (1, 2)0.35Distal stent involvement4/20 (20%)9/37 (24.32%)1Total stents, n4795Non-interpretable stents12/47 (25.53%)10/95 (10.53%)0.04Patients with any non-interpretable stent5/20 (25%)4/37 (10.81%)0.25Downstream testing4/20 (20%)3/37 (8.11%)0.23Abstract 37 Figure 1Key clinical utility outcomes with conventional CT and photon-counting CT for coronary stent assessmentCorrect answer: C",
  "authors": [
    {
      "affiliations": [
        "Royal Brompton Hospital, Guy’s and St Thomas’ NHS Foundation Trust"
      ],
      "name": "Md Imran Hossain"
    },
    {
      "affiliations": [
        "Royal Brompton Hospital, Guy’s and St Thomas’ NHS Foundation Trust"
      ],
      "name": "Vishma Porwal"
    },
    {
      "affiliations": [
        "The Hillingdon Hospital NHS Foundation Trust"
      ],
      "name": "Nazia Ehsan"
    },
    {
      "affiliations": [
        "Royal Brompton Hospital, Guy’s and St Thomas’ NHS Foundation Trust",
        "King’s College London"
      ],
      "name": "Jonathan Weir-McCall"
    }
  ],
  "title": "37 Clinical utility of conventional CT versus photon-counting CT for coronary stent assessment: a retrospective observational study",
  "uid": "f44db344-a3b9-5b1f-ac60-54dbcc5295a6"
}