Vascular Technology & Hemodynamics Flashcards
7 cards from real CVT practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Vascular Technology & Hemodynamics flashcards as text
In Poiseuille's law, if the radius of a vessel is halved, the resistance to flow will:
Answer: Increase 16-fold
Poiseuille's law states resistance is inversely proportional to the fourth power of the radius, so halving the radius increases resistance 16-fold (2^4 = 16).
A patient with an abdominal aortic aneurysm (AAA) has swirling color Doppler flow within the sac. This turbulent flow pattern is caused by:
Answer: Flow separation and recirculation within the dilated segment
Aneurysmal dilation disrupts laminar flow, causing flow separation at the dilated walls and recirculation eddies visible as swirling color Doppler patterns.
Which finding on mesenteric duplex ultrasound suggests significant celiac artery stenosis?
Answer: Peak systolic velocity greater than 200 cm/s with post-stenotic turbulence
A celiac artery PSV greater than 200 cm/s with post-stenotic turbulence is the threshold for hemodynamically significant stenosis on mesenteric duplex.
The normal spectral waveform of the superior mesenteric artery (SMA) in the fasting state is best described as:
Answer: High-resistance with absent or reversed diastolic flow
The fasting SMA has a high-resistance waveform with absent or minimal diastolic flow because the intestinal vascular bed is constricted when not digesting.
Which color Doppler aliasing pattern indicates the presence of a high-velocity stenotic jet?
Answer: Mosaic pattern of mixed colors with brightness at the stenosis
A mosaic color pattern with a bright core at the stenosis indicates aliasing and flow disturbance caused by a high-velocity jet exceeding the Nyquist limit.
Which venous Doppler finding is consistent with right heart failure or elevated central venous pressure?
Answer: Pulsatile hepatic vein waveform with prominent retrograde flow
Elevated right heart pressure transmits pulsatility into the hepatic veins, producing exaggerated pulsatile waveforms with prominent retrograde (S-wave reversal) components.
When performing a toe-brachial index (TBI), a value below which threshold indicates significant digital ischemia?
Answer: 0.6
A TBI below 0.6 is considered abnormal and indicates significant digital ischemia; below 0.15 suggests critical ischemia at the digital level.