In 18 patients with 44 coronary stents, ultra-high-resolution (UHR) PCCT angiography achieved high diagnostic accuracy for detecting ≥50% in-stent stenosis compared with invasive coronary angiography (ICA). Both readers identified all 5 stenotic stents, yielding 100% sensitivity.
Specificity and overall accuracy were 92.3% and 93.2% for reader 1 and 87.2% and 88.6% for reader 2. Most importantly, the negative predictive value was 100% for both readers, supporting UHR PCCT as a strong noninvasive technique for ruling out clinically relevant in-stent restenosis.
Stent-lumen image quality was generally good to excellent, with only 3/44 stents considered nondiagnostic by both readers. Despite residual stent blooming of approximately 38–40%, the 0.2-mm reconstruction with a sharp Bv60 kernel provided sufficient lumen visualization for reliable clinical assessment in more than 90% of stents.
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Figure 4. Ultra-high-resolution photon-counting detector CT angiography (PCD-CTA) of the heart of a 69-year-old male patient with severe aortic valve stenosis and a history of coronary stent implantation in the distal left main and proximal left anterior descending artery (LAD) (arrowhead in A, B, and C). A Three-dimensional cinematic rendering of the heart, showing the stent in the LAD. B Curved multiplanar reformation showing the absence of in-stent stenosis. The stent was rated as “excellent”—Likert 1 by one reader—and as “good”—Likert 2 by the other reader. C Invasive coronary angiography at caudal 30° view, verifying stent patency
Protocol
Detail | Value |
|---|
Scanner | NAEOTOM Alpha |
Software | syngo CT VA50; syngo.via VB60 |
Scan area | Coronary arteries as part of TAVI-CT |
Scan mode | Ultra-high resolution |
Acquisition mode | ECG-synchronized UHR PCCT angiography |
Detector slice collimation | 120 × 0.2 mm |
Matrix | 1024 × 1024 |
Field of view [mm] | 180 × 180 |
Slice thickness [mm] | 0.2 |
Reconstruction increment [mm] | 0.1 |
Reconstruction kernel | Bv60 |
Iterative reconstruction | QIR 3 |
ECG reconstruction | Automatically selected best-systolic and best-diastolic phases plus multiphase data |
Contrast agent | Iopromide, Ultravist 370 |
Contrast protocol | 70 mL contrast followed by 40 mL isotonic saline + 30 mL contrast mixture |
Injection rate | 5.0 mL/s |
Bolus triggering | Aortic root, 130-HU threshold |
Trigger delay | 10 s |
Patient preparation | No nitroglycerin or beta-blockers administered |
Key Results
Parameter | Main finding |
|---|
Study population | 18 patients / 44 coronary stents |
In-stent stenosis prevalence | 5/44 (11.4%) |
Sensitivity | 100% for both readers |
Specificity | 92.3% reader 1; 87.2% reader 2 |
Diagnostic accuracy | 93.2% reader 1; 88.6% reader 2 |
Negative predictive value | 100% for both readers |
Inter-reader agreement | 90.1%; κ = 0.72 |
Stent blooming | 37.9 ± 9.6% and 40.1 ± 8.9% |
Source:
Hagar MT, Soschynski M, Saffar R, Molina-Fuentes MF, Weiss J, Rau A, Schuppert C, Ruile P, Faby S, Schibilsky D, von zur Muehlen C, Schlett CL, Bamberg F, Krauss T. Ultra-high-resolution photon-counting detector CT in evaluating coronary stent patency: a comparison to invasive coronary angiography. European Radiology. 2024;34:4273–4283. doi:10.1007/s00330-023-10516-3.
