In the echo lab, what measurement is obtained using Doppler to determine velocity, and which equation is used to estimate the pressure gradient from velocity?

In the echo lab, what measurement is obtained using Doppler to determine velocity, and which equation is used to estimate the pressure gradient from velocity?

• A. Doppler measures velocity; Bernoulli equation is used to estimate the pressure gradient
• B. Doppler measures volume; Navier-Stokes equation
• C. Doppler measures acceleration; continuity equation
• D. Doppler measures tissue tracking; Hooke's law

Answer: (A)

Doppler in the echo lab is used to measure the velocity of blood flow through a valve or vessel. From that velocity, the pressure gradient across a stenotic orifice is estimated using the Bernoulli principle, typically the simplified form ΔP = 4 v^2, where v is the peak velocity through the orifice. This relationship comes from energy balance across the narrowed passage: faster flow implies a larger pressure drop to propel the blood through the constriction. The measurement relies on the Doppler shift to determine velocity, and the gradient estimate uses the Bernoulli equation. The other ideas—volume measurement, acceleration, or tissue tracking—aren’t what Doppler velocity feeds into the pressure gradient in this context.

Doppler in the echo lab is used to measure the velocity of blood flow through a valve or vessel. From that velocity, the pressure gradient across a stenotic orifice is estimated using the Bernoulli principle, typically the simplified form ΔP = 4 v^2, where v is the peak velocity through the orifice. This relationship comes from energy balance across the narrowed passage: faster flow implies a larger pressure drop to propel the blood through the constriction. The measurement relies on the Doppler shift to determine velocity, and the gradient estimate uses the Bernoulli equation. The other ideas—volume measurement, acceleration, or tissue tracking—aren’t what Doppler velocity feeds into the pressure gradient in this context.