Abstract
OBJECTIVE: To evaluate the patient-, vessel- and segment-based diagnostic performance of photon-counting detector CT (PCD-CT) compared to energy-integrating detector CT (EID-CT) for detecting ≥ 50% or ≥ 70% stenosis using invasive coronary angiography (ICA) as a reference standard. MATERIALS AND METHODS: Patients with stable chest pain and ≥ 50% stenosis detected on dual source PCD-CT who subsequently underwent ICA were prospectively enroled. Diagnostic accuracy was calculated for PCD-CT vs ICA and additionally for a patient cohort scanned with EID-CT with similar risk profiles and disease prevalence. A Monte Carlo simulation based on diagnostic accuracy parameters was performed to estimate the potential reduction in ICA referrals. RESULTS: A total of 143 patients (66 ± 9 years, 27.3% female) with 572 vessels and 2431 segments were evaluated with PCD-CT and ICA. Regarding EID-CT, 109 patients (65 ± 9 years, 31.0% female), 436 vessels and 1853 segments were assessed, with every patient undergoing ICA. PCD-CT demonstrated significantly higher accuracy than EID-CT in detecting ≥ 50% stenosis: 88.1% vs 77.9% (patient level), 91.6% vs 77.8% (vessel level), and 97.7% vs 92.4% (segment level) (p < 0.01 for all). For detecting ≥ 70% stenosis, PCD-CT also showed higher accuracy than EID-CT: 90.9% vs 70.6% (patient level), 94.6% vs 80.9% (vessel level), and 98.6% vs 94.1% (segment level) (p < 0.01 for all). We demonstrated a potential mean reduction of 14.8% in ICA referrals when utilising PCD-CT compared to EID-CT. CONCLUSIONS: PCD-CT provides improved per-patient, per-vessel and per-segment diagnostic performance in detecting obstructive CAD in symptomatic patients when compared to patients scanned on EID-CT. PCD-CT may lead to a significant decrease in ICA utilisation. KEY POINTS: Question Accurate coronary CT angiography guides treatment, but its diagnostic accuracy is limited by various factors. Findings Photon counting detector (PCD)-CT improved diagnostic performance in detecting ≥ 50% or ≥ 70% stenosis, potentially reducing unnecessary ICA referrals by 14.8%. Clinical relevance PCD-CT improves diagnostic accuracy over EID-CT and may reduce unnecessary ICA.