Duplex Ultrasound Column Interruption Duration Measurement
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Solution Overview
Problem
The accuracy of traditional ambulatory venous pressure measurements (AMVP) using dorsal foot vein (DFV) is questionable, as it does not accurately reflect the pressure dynamics in the deep vein system, particularly in patients with chronic venous disease (CVD), due to differences in pressure profiles between the superficial and deep vein systems.
Innovation Solution
A method using duplex ultrasound to directly measure column interruption duration (CID) in the deep vein system by observing valve actions and blood flow through selected veins in the lower leg, eliminating the need for dorsal foot measurements, allowing for more precise assessment of calf pump function.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional ambulatory venous pressure measurements (AMVP) using dorsal foot vein are performed, then the measurement process is simple and accessible, but the measurement accuracy is compromised because it does not reflect deep vein system pressure dynamics
Solution Approach 1:
The patent replaces the mechanical pressure measurement system (needle insertion into dorsal foot vein) with an acoustic imaging system (duplex ultrasound). The ultrasound system uses sound waves to visualize blood flow and valve motion in deep veins, eliminating the need for invasive pressure measurements in superficial veins while providing more accurate assessment of deep vein system dynamics
Solution Approach 2:
The patent introduces blood flow velocity and valve motion as intermediary parameters that mediate between the ultrasound measurement and deep vein pressure dynamics. By measuring the velocity of blood flow and the motion of valves in the deep vein system, the system indirectly but accurately reflects pressure changes without requiring direct pressure measurement
2Reliability
If dorsal foot vein measurements are used to assess calf pump function, then the procedure is non-invasive and easy to perform, but the reliability of the assessment is reduced due to pressure differences between superficial and deep vein systems
Solution Approach 1:
The patent segments the venous system assessment by separately evaluating the deep vein system and superficial vein system. The duplex ultrasound focuses specifically on visualizing deep veins (popliteal vein, femoral vein) and their valves, while the superficial dorsal foot vein is used only for timing valve closure. This segmentation allows accurate assessment of deep vein pressure dynamics without the confounding effects of superficial vein pressure differences
3Measurement precision
If direct observation of deep vein valve actions is implemented, then the measurement accuracy of column interruption duration is improved, but the device complexity and measurement difficulty increase
Solution Approach 1:
The patent replaces direct visual observation of valve actions (which would require invasive catheterization) with acoustic imaging using duplex ultrasound. The ultrasound system uses sound wave reflection and Doppler effects to visualize valve leaflet motion and blood flow patterns, making the observation of deep vein valve actions non-invasive and clinically feasible
Solution Approach 2:
The patent employs color Doppler imaging to visualize blood flow direction and velocity. The color coding of blood flow (typically red for flow toward transducer, blue for flow away) provides intuitive visual feedback that makes it easier to detect and measure valve opening and closing actions by observing the cessation and resumption of colored flow signals
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach provides more reliable measurements of CID, accurately reflecting the calf pump's dynamics and pressure changes, potentially improving the diagnosis of chronic venous hypertension by distinguishing between superficial and deep vein system pressures, thereby offering a more accurate assessment of venous reflux and pump function.
Implementation Method 1
A method using duplex ultrasound to directly measure column interruption duration (CID) in the deep vein system by observing valve actions and blood flow through selected veins in the lower leg
Data Source
AI summary
A method of measuring column interruption duration in a selected lower leg vein of a patient without undertaking dorsal foot measurements. The method includes the step of selecting a vein in the lower leg to be examined and selecting a valve in the vein to be observed. The valve's actions will be observed with Duplex ultrasound and timed. The method then effects calf muscle ejection and observing the action of the selected valve in the respective vein selected. The valve can be observed for opening or closing action, or action of blood flow (or lack of flow) through the valve. The CID is then determined calculated based on the timing of events observed with ultrasound. The ultrasound can be Duplex ultrasound; invasive measurements are not required.