Select ~110 keV VMI for optimal artifact reduction. The authors identified 110 keV as the best balance, achieving strongest reduction of hypo- and hyperdense artifacts without overcorrection.
Use 110 keV specifically to improve peri-prosthetic bone assessment. Qualitative ratings showed significantly improved evaluation of acetabular bone at this energy level.
Avoid high-keV VMI for soft tissue and vessel assessment. The authors report reduced image contrast at higher keV, making pelvic organs and iliac vessels better assessed at lower energies or conventional images.
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Figure 4. Image example of a patient with THR and predominantly hypodense artifacts. Optimal reduction of artifacts and assessment of circumjacent bone is provided in VMI at 110 keV, whereas VMI of higher energy levels show relevant overcorrection of the artifact
Source: Schreck et al., European Radiology, 2023.
Protocol
Detail | Value |
|---|
Scanner | NAEOTOM Alpha |
Software | VA40 |
Scan area | Abdomen / pelvis |
Scan mode | QuantumPlus Portal-venous abdominopelvic PCCT |
Tube voltage [kV] | 120 |
IQ level | IQ170 |
Dose modulation | CARE Dose4D |
CTDIvol [mGy] | n.a. |
DLP [mGy*cm] | n.a. |
Effective dose [mSv] | n.a. |
Rotation time [s] | 0.5 |
Pitch | 0.8 |
Slice collimation [mm] | 144 × 0.4 |
Slice width [mm] | 2.0 (normalized; VMI source 0.6) |
Reconstruction increment [mm] | 1.0 |
Reconstruction kernel | Br36 (CI) | Qr36 (VMI/SPP) |
Iterative reconstruction | QIR 4/4 |
keV level [keV] | 70, 110, 150, 190 |
Schreck J, Laukamp KR, Niehoff JH, et al. Metal artifact reduction in patients with total hip replacements: evaluation of clinical photon counting CT using virtual monoenergetic images. Eur Radiol. 2023;33(12):9286–9295. doi:10.1007/s00330-023-09879-4
