Photon-counting CT (PCCT) was used to characterize suspected HeartMate 3 (HM3) left ventricular assist device (LVAD) outflow graft stenosis and generate patient-specific computational fluid dynamics (CFD) models to determine whether visually apparent stenoses were haemodynamically significant.
Despite radiological cross-sectional area reductions of 29–61%, simulated pressure gradients remained low (1–9 mmHg), suggesting that many asymptomatic patients with moderate extrinsic graft compression may not require immediate intervention. The study demonstrates that anatomical stenosis severity alone may overestimate functional obstruction.
PCCT was selected because of its improved spatial resolution, reduced metal artefacts, and superior contrast performance around metallic LVAD components, enabling accurate segmentation for CFD modelling.
Access publication
Figure 6. TKE (mJ) for the different stenosis severities and device flow (L/min) are shown. Images are acquired at 5.5 L/min device flow. Values < 75 are transparent to better highlight the higher values. OS, original stenosis; AS1, augmented stenosis 1; AS2, augmented stenosis 2.
Source: Ohlsson L, Sandstedt M, Papageorgiou JM, et al. Haemodynamic significance of extrinsic outflow graft stenoses during HeartMate 3™ therapy. European Heart Journal – Imaging Methods and Practice. 2024.
Protocol
Detail | Value |
|---|
Scanner | NAEOTOM Alpha |
Scan area | Heart and LVAD outflow graft |
Scan mode | QuantumPlus |
Tube voltage [kV] | 120 |
Effective mAs [mAs] | Automatic (Care Dose4D) |
IQ level | 70 |
Dose modulation | Care Dose4D |
DLP [mGy·cm] | n.r. |
Pitch | 0.17 |
Matrix | 512 × 512 |
Slice collimation [mm] | 0.4 mm detector |
Slice width [mm] | 0.4 mm (segmentation); 1.5 mm (radiological review) |
Reconstruction increment [mm] | 1.0 mm |
Reconstruction kernel | Bv56 (segmentation); Bv40 (radiology) |
Iterative reconstruction | n.r. |
Reconstruction type | Virtual monoenergetic images (110 keV) |
ECG gating | Retrospective cardiac CT |
Contrast agent | Omnipaque 350 mgI/mL |
Contrast volume | 109–110 mL |
Flow rate | n.r. |
Saline dilution | Yes |
Phase used | Best diastolic phase |
