Fig 1.
ImageJ custom plugin to detect area variations: The top figure shows an example of B-mode image with a rectangular Region of Interest (ROI) and synchronized ECG trace, together with a list of ROIs and collected measurements.
The bottom figure shows the indicative JVP trace with a, c, v peaks and x, y troughs synchronized with the ECG trace. Systole and diastole phase as well as the corresponding opening and closure of the tricuspid valve and various time intervals (Δt) are also shown.
Fig 2.
Flow diagram showing subject enrolment and exclusion.
Table 1.
Clinical characteristics of subjects.
Fig 3.
Mean ensemble autocorrelograms for the CVP and IJV CSA pulse signals (aggregated for all 34 subjects).
Fig 4.
(a) Normalized time series signals; (b) autocorrelation signals; and (c) periodogram of the CVP and IJV CSA pulses for Subject 19.
Table 2.
Descriptive and aggregated autocorrelation results for both the central venous pressure (CVP) and internal jugular vein cross-sectional area (IJV-CSA) signals.
Table 3.
Correlations and lag times between the central venous pressure (CVP) and internal jugular vein cross-sectional area (IJV-CSA) signals for the respective subjects.
Fig 5.
Regression scatter plot showing predicted and measured mean CVP values for the 34 subjects (units are in cmH2O).
Table 4.
Refined multiple linear regression model with mean central venous pressure (CVP) as the response variable.