Objective: Arterial wall deformation, stiffness, and luminal pressure are well-recognized predictors of cardiovascular diseases but intertwined. Establishing a relationship among these three predictors is therefore important for comprehensive assessment of the circulatory system, but very few studies focused on this.
Methods: In this study, we first derived a mathematical description for localized luminal pressure change ( ∆p) as a function of arterial wall strains ( ε) and shear modulus ( μT) in the transverse plane; the arterial wall was modelled as a transversely isotropic and piecewise linearly-elastic material. Finite element simulations (FES) and in vitro fluid-driven inflation experiments were performed on arteries with both normal and abnormal geometries. ε and μT in the experimental study were estimated by an ultrasound elastographic imaging framework (UEIF).
Results: FES results showed good accuracy (percent errors ≤ 6.42%) of the proposed method for all simulated artery models. Experimental results showed good repeatability and reproducibility. Estimated ∆p pp values (average peak-to-peak pressure change) compared with pressure meter measurements in two normal geometry phantoms and an excised aorta were 65.95 ± 4.29 mmHg vs. 66.45 ± 3.80 mmHg, 60.49 ± 1.82 mmHg vs. 59.92 ± 2.69, and 36.03 ± 1.90 mmHg vs. 38.8 ± 3.21 mmHg, respectively. For the artery with abnormal geometry mimicking a simple plaque shape, the feasibility of the proposed method for ∆p estimation was also validated.
Conclusion: Results demonstrated that UEIF with the proposed mathematical model, which lumped wall deformation, stiffness and luminal pressure, could estimate the localized dynamic luminal pressure change noninvasively and accurately.