A tailored PCCT coronary CTA protocol achieved 90% fully diagnostic examinations, significantly outperforming the previous EID-CT protocol (78%), despite imaging an older population with substantially higher coronary calcium burden.
Diagnostic image quality remained high even in heavily calcified patients, with 77% of examinations remaining fully diagnostic at Agatston scores ≥400 versus only 26% using EID-CT.
Selective use of UHR mode (96 × 0.2 mm) for patients with Agatston ≥100 or coronary stents reduced calcium blooming and improved stenosis assessment, while maintaining comparable Agatston scoring across scanner generations.
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Fig. 3. Curved multiplanar reformats of LAD in a male study participant examined at age 52 in the SCAPIS baseline examination (a) and in the SCAPIS reexamination at age 63 (b, c). Images are reconstructed using standard reconstruction at baseline, I26f/6 (a), and ultra-high resolution mode in the reexamination, Bv48 (b), and Bv64 (c). There is a marked progression of atherosclerosis with a severe stenosis in a partially calcified plaque (arrow). The Agatston score increased from 95 to 1362 between the two studies.
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Source: Lidén et al., European Journal of Radiology, 2026.
Protocol
Detail | Value |
|---|
Scanner | NAEOTOM Alpha |
Software | VB10 |
Scan area | Coronary CTA |
Scan mode | Adaptive protocol (High-pitch / Sequential / UHR Sequential) |
Scan direction | Helical or sequential depending on protocol |
Tube voltage [kV] | 140 (standard CCTA), 120 (UHR mode) |
Effective mAs [mAs] | Automatic modulation |
IQ level | 64 (standard), 56 (UHR) |
Dose modulation | Automatic |
CTDIvol [mGy] | 10.6 (median) |
DLP [mGy*cm] | 134 (median) |
Effective dose [mSv] | 2.7 (median) |
Rotation time [s] | 0.25s |
Pitch | High-pitch mode when applicable |
Matrix | 1024 × 1024 |
Slice collimation [mm] | 144 × 0.4 (standard), 96 × 0.2 (UHR) |
Slice width [mm] | n.a. |
Reconstruction increment [mm] | n.a. |
Reconstruction kernel | Bv44, Bv56, Bv48, Bv64 |
Iterative reconstruction | n.a. |
Spectral reconstruction | SPP (Qr44/Qr48) |
Contrast agent | Omnipaque 350 mg I/mL |
Contrast volume | Injection duration 12–16 s |
Flow rate | Weight-based (see protocol) |
Bolus triggering | Automated |
Patient preparation | Beta-blocker + sublingual glyceryl nitrate |
ECG gating | Prospective ECG-triggered |
Calcium scoring | Non-contrast CAC scan before CTA |
Adaptive Coronary CTA Protocol
Detail | Setting |
|---|
Agatston = 0, HR <60 bpm | High-pitch helical |
Agatston 1–99 | Sequential standard mode |
Agatston ≥100 | Sequential UHR mode |
Coronary stents present | Sequential UHR mode |
HR >70 bpm / arrhythmia | Dual-phase acquisition (30–80%) |
UHR Mode Settings
Detail | Value |
|---|
Detector mode | Ultra-high resolution |
Tube voltage [kV] | 120 |
IQ level | 56 |
Slice collimation [mm] | 96 × 0.2 |
Reconstruction kernels | Bv48, Bv64 |
Primary indication | Agatston ≥100 or coronary stents |
Intended benefit | Reduced calcium blooming and improved stenosis grading |
Key Results
Metric | PCCT | EID-CT |
|---|
Fully diagnostic examinations | 90% | 78% |
Diagnostic quality at Agatston ≥400 | 77% | 26% |
Diagnostic quality at Agatston 100–399 | 87% | 50% |
Diagnostic quality at Agatston 0 | 93% | 88% |
Agatston score comparability | Equivalent | Reference |
Reference
Lidén M, Nyberg G, Aurumskjöld ML, et al. Improved coronary CT angiography image quality using photon-counting detector CT in SCAPIS reexamination: scan protocol and comparative analysis. Eur J Radiol. 2026;201:112920.
