Related Experiment Video
Updated: Sep 9, 2025
High-Resolution Cardiac Positron Emission Tomography/Computed Tomography for Small Animals
Published on: December 16, 2022
Optimal post-contrast timing for photon-counting CT-based myocardial extracellular volume quantification in a swine
Shouyu Bao1, Min Yang1, Peng Liu1
1Department of Radiology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China. No.197 Ruijin Er Road Shanghai, Shanghai CN200025, China.
Rationale And Objectives:
Advances in computed tomography (CT) have enabled myocardial extracellular volume (ECV) quantification, but the optimal post-contrast timing for CT-derived ECV remains undefined. In this preclinical study using a swine model, we aimed to determine the optimal post-contrast acquisition time for photon-counting CT (PCCT)-derived ECV using cardiac magnetic resonance (CMR) as the reference standard.
Materials And Methods:
Twenty-three CMR and PCCT scans were performed on infarcted swine, and nine scans on healthy controls. PCCT scans were acquired at 3-, 5-, 7-, 9-, 12-, and 15-minutes after contrast administration. Pearson correlation coefficients (r) and intraclass correlation coefficients (ICCs) were calculated between PCCT- and CMR-derived ECV across all myocardial segments, infarcted and normal myocardium. Receiver operating characteristic (ROC) curve analysis was performed to evaluate the diagnostic performance of PCCT-ECV in differentiating LGE-positive from LGE-negative myocardial segments. Subgroup analyses were conducted based on heart rate (HR).
Results:
Across all segments, r ranged from 0.79 to 0.91 and ICCs from 0.88 to 0.95 and the area under the ROC curve (AUC) values ranged from 0.799 to 0.847 (all p < 0.001). Peak correlation and agreement occurred at 5 min (r = 0.91; ICC = 0.95, 95 % CI: 0.92-0.96), with similarly high values at 3 and 7 min (r = 0.90; ICC = 0.93 and 0.94, respectively), followed by a gradual decline. At elevated HRs (>84 bpm), PCCT still maintained robust agreement with CMR (ICC = 0.78-0.92) and satisfactory diagnostic performance (AUC values ranged from 0.677 to 0.777).
Conclusion:
PCCT enables accurate and consistent ECV quantification with strong concordance to CMR from 3 to 7 min post-contrast in swine models, providing a wide temporal window for clinical scanning. This was further confirmed by ROC analysis, and the method demonstrated robustness across varying heart rates.
