3D ultrasound-based CFD for carotid flow prediction: a reproducibility study

Image-based CID has been a prime technique for studying arteriosclerosis, plaque formation, aneurysm rupture and bypass design in the past decade. The imaging techniques used for vessel geometry acquisition are usually X-ray (CT-scan), intravascular ultrasound or most frequently MRI. It has been shown in previous studies that 3D extravascular ultrasound (3D US) can provide a cost-effective alternative for imaging superficial arteries like the carotid bifurcation or femoral arteries. In this study, the carotid bifurcation of 9 healthy subjects have been scanned twice within two to six weeks. CFD models for each subject and each scan were built using the corresponding anatomical data acquired in vivo. Overall reproducibility was satisfactory. Two main sources of error were identified. (1) Blurred border between vessel lumen and endothelium, causing the operator to overestimate the lumen area; and (2) altered neck angles. It is expected that with further improvement in ultrasound image quality and with standardisation of the imaging protocol, 3D US has a huge potential to become a viable alternative to MRI both for clinical and research uses.