ARDMS SPI Hemodynamics and Vascular Flow Principles 2

Question 1

The pulsatility index (PI) is calculated as:

Accepted Answer

(PSV − EDV) / mean velocity

Answer

The Pulsatility Index = (Peak Systolic Velocity − End Diastolic Velocity) / Mean Velocity, providing a measure of downstream resistance.

Question 2

Which Doppler finding is most indicative of a hemodynamically significant proximal arterial stenosis?

Accepted Answer

Monophasic, low-resistance tardus-parvus waveform distal to the stenosis

Answer

A tardus-parvus (slow rise, small amplitude) waveform distal to a significant stenosis reflects the damped, delayed transmission of the pulse through the obstruction.

Question 3

Poiseuille's Law states that blood flow through a vessel is most sensitive to changes in which parameter?

Accepted Answer

Vessel radius

Answer

Flow is proportional to the fourth power of radius; halving the radius reduces flow 16-fold, making radius by far the most powerful determinant of vascular resistance.

Question 4

In a normal hepatic vein Doppler waveform, the waveform is expected to be:

Accepted Answer

Triphasic with both antegrade and retrograde components reflecting cardiac pulsatility

Answer

Normal hepatic veins transmit right atrial pressure changes, producing a triphasic waveform with S, D, and A waves including a brief retrograde A wave.

Question 5

The spectral window in a normal arterial Doppler waveform represents:

Accepted Answer

The clear area below the spectral envelope indicating organized laminar flow

Answer

The clear spectral window below the waveform envelope reflects the narrow, uniform velocity distribution of laminar flow where few cells travel at intermediate velocities.

ARDMS SPI - ARDMS Sonography Principles and Instrumentation Practice Test

ARDMS SPI - ARDMS Sonography Principles and Instrumentation Practice Test

ARDMS SPI Hemodynamics and Vascular Flow Principles 2