Ultra-high-resolution (UHR) photon-counting CT pulmonary angiography significantly improved visualization of peripheral pulmonary arteries and increased radiologists' diagnostic confidence compared with state-of-the-art dual-energy EID-CT.
UHR-PCD-CT achieved substantially higher pulmonary arterial enhancement (568–623 HU vs. 397 HU) while maintaining similar SNR and CNR, enabling superior subjective image quality and iodine map quality.
A low-dose UHR protocol (IQ25) reduced radiation dose by approximately 36% compared with EID-CT while maintaining the same image quality and diagnostic confidence as the higher-dose UHR protocol (IQ50).
Access publication
Figure 4. Increased peripheral pulmonary artery visibility with ultra-high-resolution photon-counting CT. UHR-PCD-CTPA at IQ50 (A) and IQ25 (B) vs. EID-CTPA (C). Representative measurements of the minimal distance of the last discernible pulmonary artery branch to the pleura are shown (orange line, in mm). CTPA, CT pulmonary angiography; EID, energy-integrating detector; IQ, image quality index; PCD, photon-counting detector; UHR, ultra-high resolution
Source: Pannenbecker P, Rüth C, Grunz JP, et al. Increasing pulmonary artery visibility and diagnostic confidence with ultra-high resolution photon-counting detector CT pulmonary angiography. European Radiology. 2026.
Protocol
Detail | Value |
|---|
Scanner | NAEOTOM Alpha.Peak |
Software | VB10 PCCT VB80D sybgo.via |
Scan area | CT Pulmonary Angiography (CTPA) |
Scan mode | Quantum HD |
Acquisition mode | Photon-counting CT |
Scan direction | Craniocaudal |
Tube voltage [kV] | 140 |
Effective mAs [mAs] | IQ25 or IQ50 (vendor-specific IQ level) |
IQ level | 25 or 50 |
Dose modulation | IQ-based automatic exposure control |
CTDIvol [mGy] | IQ25: 3.0 ± 1.0; IQ50: 6.7 ± 2.4 |
DLP [mGy·cm] | Not reported |
Pitch | 3.2 (Flash mode) |
Matrix | n.r. |
Slice collimation [mm] | 120 × 0.2 |
Slice width [mm] | 0.4 |
Reconstruction kernel | Bv48 |
Reconstruction | 55 keV virtual monoenergetic images (VMI) |
Iodine maps | Yes |
Contrast agent | Imeron 350 |
Contrast volume | 40 mL |
Flow rate | 4 mL/s |
Bolus triggering | 100 HU in pulmonary trunk; 5 s delay |
Patient preparation | Standard pulmonary embolism protocol |
Comparison protocol (reference EID-CT)
Detail | Value |
|---|
Scanner | SOMATOM Force |
Acquisition | Dual-energy EID-CT |
Tube voltage | 90/Sn150 kV |
Pitch | 0.55 |
Slice collimation | 2 × 96 × 0.6 mm |
Slice width | 0.6 mm |
Reconstruction kernel | Bv36 |
Contrast volume | 50 mL |
CTDIvol | 4.7 ± 2.7 mGy |
