Comparison of Photon-Counting and Energy-Integrating Detector CT for Evaluation of Myocardial Late Iodine Enhancement

Purpose To compare photon-counting detector (PCD) CT and energy-integrating detector (EID) CT for the evaluation of myocardial late iodine enhancement (LIE), a CT marker of myocardial fibrosis. Materials and Methods This retrospective cohort study included patients undergoing preprocedural evaluation for ventricular ablation from April 2022 to March 2024. Quantitative region of interest measurements and qualitative Likert scale ratings were compared between modalities. Primary outcome metrics included signal intensity ratio, signal-to-noise ratio, and contrast-to-noise ratio (CNR). A secondary analysis in a subset of 51 patients with MRI as the reference evaluated sensitivity and balanced accuracy relative to late gadolinium enhancement. Results A total of 150 patients (74 PCD CT, 76 EID CT) were included. PCD CT demonstrated higher CNR for both LIE to myocardium (4.2 [IQR, 1.7] vs 2.6 [IQR, 1.5]; <i>P</i> < .001) and blood pool to myocardium (4.0 [IQR, 1.7] vs 2.6 [IQR, 1.5]; <i>P</i> = .001) compared with EID CT. Mean qualitative image quality scores were higher for PCD CT than for EID CT (3.1 [IQR, 0.8] vs 2.5 [IQR, 0.8]; <i>P</i> < .001). PCD CT also showed lower rates of qualitatively degrading streak artifact (37.3% vs 55.3%; <i>P</i> = .04) and photon starvation (13.3% vs 32.9%; <i>P</i> = .008). In the subset of patients with MRI as a reference, per-segment sensitivity (80.1% vs 49.4%) and balanced accuracy (86.3% vs 72.9%; <i>P</i> < .001) were higher for PCD CT than for EID CT. Conclusion PCD CT improved image quality metrics, reduced suboptimal examination rate, and provided higher per-segment sensitivity for LIE compared with EID CT. <b>Keywords:</b> CT-Photon Counting, CT-Angiography, Cardiac <i>Supplemental material is available online for this article.</i> © RSNA, 2026.