Non-Invasive Estimation of Localized Dynamic Luminal Pressure Change by Ultrasound Elastography in Arteries With Normal and Abnormal Geometries.

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.