K19 - Ultrasound-Based Method for Noninvasive Estimation of Central Venous Pressure

Introduction: : Central venous pressure (CVP) is a critical clinical parameter for assessing hemodynamic stability. The gold standard catheter-based measurement method is invasive and poses associated risks. As an alternative, CVP can be estimated via pressure in the internal jugular vein (IJV), which connects directly to the right atrium. Previously, ultrasound (US)-based methods have been developed to noninvasively assess venous pressure by compressing tissue with a transducer and measuring surface pressure with external sensors as the vein collapses. However, these methods are often semi-quantitative due to tissue heterogeneity.

We propose an approach that combines US-guided strain and shear wave elasticity imaging (SWEI) to noninvasively and quantitatively estimate CVP. Specifically, a transducer is used to apply surface deformation to gradually compress the neck tissue, collapsing the underlying IJV while simultaneously acquiring B-mode and SWEI data. The strain and Young’s modulus of the overlying sternocleidomastoid muscle (SCM) are estimated. CVP is calculated under two assumptions: (1) axial stress in the SCM can be computed from Young’s modulus and axial strain maps; and (2) at the point of IJV collapse, the axial stress in the adjacent SCM equals the CVP.

Materials and

Methods: : To validate the proposed approach, finite element analysis was conducted using MATLAB’s PDE toolbox. A model of IJV, SCM, and common carotid artery within background tissue was constructed based on anatomical features derived from B-mode images during the external mechanical compression applied at the skin surface (Fig. 1a). Young's modulus and Poisson’s ratio of the SCM were set to 20 kPa and 0.4999, respectively. Internal pressure within the IJV was varied between 5 mmHg and 15 mmHg. External mechanical compression was gradually applied until the IJV collapsed (Fig. 1b). Maps of axial strain and Young’s modulus that can be measured using US imaging were recorded throughout the process, and a region of interest (ROI) within the SCM adjacent to the IJV was selected (Fig. 1c). Axial stress was calculated from the axial strain and Young’s modulus maps. At the point of IJV collapse, the axial stress within the ROI was considered equal to the IJV pressure. The estimated IJV pressures were compared to the ground truth values using mean absolute percentage error (MAPE) and coefficient of determination (R²).

Results, Conclusions, and Discussions:: The comparison between true and estimated IJV pressures is shown in Fig. 1d. The calculated MAPE was 1.08%, and the R² value was 0.999, indicating high accuracy and a strong linear correlation between estimated and true pressures. These results demonstrate the feasibility of using US-guided strain and SWEI measurement for quantitative and noninvasive assessment of venous pressure. This proof-of-concept study highlights the potential of the proposed approach for accurate and noninvasive CVP estimation, paving the way for safer bedside hemodynamic monitoring.

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