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RVS practice questions

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Question 1Vascular Technology

During a lower extremity venous duplex examination, which finding best supports the diagnosis of an acute deep vein thrombosis rather than a chronic one?

  1. A vein demonstrating continuous augmented flow with a normal phasic pattern
  2. A vein that is partially compressible with a thickened, echogenic wall and calcification
  3. A vein with spontaneous flow that increases during distal augmentation maneuvers
  4. A vein that is non-compressible with hypoechoic lumen and no detectable flow Correct answer.

Explanation

Acute thrombosis typically produces a vein that fails to compress, contains hypoechoic to anechoic thrombus, and may show absent or reduced spontaneous and augmented flow. Chronic post-thrombotic change instead shows an echogenic, thickened, often calcified wall with partial compressibility and collateral formation.

Question 2Vascular Technology

A carotid duplex shows a peak systolic velocity of 240 cm/s at the origin of the internal carotid artery with spectral broadening and elevated end-diastolic velocity. What is the most appropriate interpretation?

  1. Less than 50% diameter stenosis
  2. A complete occlusion of the internal carotid artery
  3. A hemodynamically significant stenosis of roughly 50% or greater Correct answer.
  4. A normal velocity profile attributable to high cardiac output

Explanation

A peak systolic velocity above approximately 125 cm/s at the ICA origin, together with spectral broadening and elevated end-diastolic velocity, is the standard threshold for a hemodynamically significant stenosis of 50% or greater. Complete occlusion would show no detectable flow rather than very high velocities.

Question 3Vascular Technology

Which parameter is used to calculate the resistive index of an arterial waveform?

  1. Pulsatility index multiplied by the vessel diameter
  2. The difference between peak systolic and end-diastolic velocity divided by peak systolic velocity Correct answer.
  3. End-diastolic velocity divided by peak systolic velocity
  4. Peak systolic velocity divided by mean velocity

Explanation

The resistive index is (peak systolic velocity minus end-diastolic velocity) divided by peak systolic velocity. It reflects downstream resistance and normally ranges from about 0.5 to 0.7 in renal and other low-resistance beds.

Question 4Vascular Technology

During a segmental limb pressure study, a thigh cuff pressure is 40 mm Hg higher than the contralateral thigh and the ipsilateral ankle pressure. What does this pattern most likely indicate?

  1. Iliac artery stenosis or occlusion Correct answer.
  2. Superficial femoral artery stenosis or occlusion
  3. Venous insufficiency of the limb
  4. Normal physiologic asymmetry

Explanation

A high thigh pressure relative to the ankle and the opposite limb indicates an obstructive lesion proximal to the thigh cuff, which is the iliac segment. More distal femoropopliteal disease would lower pressures at and below the thigh cuff rather than elevate the thigh reading.

Question 5Vascular Technology

Which finding on a renal artery duplex study most directly suggests a hemodynamically significant stenosis?

  1. A renal artery diameter of 6 mm on grayscale imaging
  2. A peak systolic velocity of 300 cm/s at the stenosis with a post-stenotic spectral tardus-parvus pattern Correct answer.
  3. A renal-to-aortic velocity ratio of 1.5
  4. A resistive index of 0.60 in the interlobar arteries

Explanation

A focal peak systolic velocity above roughly 180 to 200 cm/s, often combined with a renal-to-aortic ratio greater than 3.5, supports significant stenosis, and downstream tardus-parvus waveforms confirm the hemodynamic effect. A resistive index of 0.60 and a normal vessel caliber are unremarkable.

Question 6Vascular Technology

What is the primary purpose of performing the Valsalva maneuver during a venous duplex examination of the lower extremities?

  1. To assess the competency of deep and perforating venous valves Correct answer.
  2. To measure the ankle-brachial index
  3. To differentiate acute from chronic thrombus
  4. To increase arterial inflow to the limb

Explanation

The Valsalva maneuver raises intra-abdominal pressure and transiently reverses venous flow; a reflux duration exceeding about one second in the femoral or popliteal veins indicates valvular incompetence. It does not distinguish acute from chronic thrombus or measure arterial indices.

Question 7Vascular Technology

A patient presents with a pulsatile abdominal mass. On duplex, which finding is most specific for an abdominal aortic aneurysm rather than a normal aorta?

  1. A peak systolic velocity of 80 cm/s in the aorta
  2. An infrarenal aortic diameter of 3.5 cm Correct answer.
  3. Aortic wall calcification on grayscale imaging
  4. Aortic pulsatility with a triphasic waveform

Explanation

An infrarenal aortic diameter of 3.0 cm or greater defines an aneurysm, so a 3.5 cm measurement is diagnostic. Calcification, low-normal velocities, and pulsatility are nonspecific findings that may appear in normal or atherosclerotic aortas.

Question 8Vascular Technology

Which waveform pattern is expected in a normal resting lower extremity artery at the level of the dorsalis pedis?

  1. Monophasic with continuous forward flow
  2. Triphasic with a sharp systolic peak, early diastolic reversal, and late diastolic forward flow Correct answer.
  3. Biphasic with loss of diastolic reversal
  4. Tardus-parvus with a delayed upstroke

Explanation

Normal resting peripheral arteries show a triphasic pattern: a steep systolic upstroke, a brief early diastolic flow reversal, and a small late diastolic forward component. Loss of reversal or monophasic flow suggests proximal obstructive disease.

Question 9Vascular Technology

An ankle-brachial index of 0.75 in a symptomatic patient is best interpreted as which of the following?

  1. Normal arterial perfusion
  2. An invalid study because the ABI cannot fall below 0.9
  3. Severe peripheral arterial disease requiring immediate intervention
  4. Mild to moderate peripheral arterial disease Correct answer.

Explanation

An ABI between roughly 0.5 and 0.9 corresponds to mild to moderate peripheral arterial disease, while values below 0.5 indicate severe disease. An ABI of 1.0 to 1.4 is generally considered normal.

Question 10Vascular Technology

A transcranial Doppler examination of the middle cerebral artery shows a mean velocity of 180 cm/s with a high-resistance waveform in a patient with subarachnoid hemorrhage. What is the most likely explanation?

  1. Vasospasm of the middle cerebral artery Correct answer.
  2. Increased intracranial pressure with absent diastolic flow
  3. Complete occlusion of the internal carotid artery
  4. Normal variation in cerebral blood flow

Explanation

Elevated mean velocities in the middle cerebral artery, typically above 120 to 150 cm/s with increasing pulsatility, suggest vasospasm after subarachnoid hemorrhage. Very high velocities with a high-resistance pattern reflect narrowing of the vessel lumen.

Question 11Vascular Technology

When performing a duplex examination of a hemodialysis access graft, which finding suggests a failing access?

  1. A venous outflow pressure that decreases during dialysis
  2. A flow volume of 1200 mL/min with a uniform diameter
  3. A focal velocity increase with a velocity ratio greater than 2:1 at a stenosis Correct answer.
  4. A brachial artery diameter of 5 mm

Explanation

A focal velocity elevation with a ratio greater than 2:1 compared with the adjacent segment indicates a hemodynamically significant stenosis that may threaten access patency. Access flow below about 500 to 600 mL/min and elevated static venous pressures are additional indicators of failure.

Question 12Vascular Technology

Which factor most affects the accuracy of Doppler velocity measurements when the angle of insonation is not corrected?

  1. The cosine of the angle between the beam and the vessel Correct answer.
  2. The sample volume length
  3. The transducer frequency
  4. The wall filter setting

Explanation

The Doppler equation includes the cosine of the angle of insonation, so velocity estimates are highly sensitive to angle error. Angles greater than 60 degrees produce unacceptable error, which is why steering and angle correction are essential.

Question 13Vascular Technology

A patient with a suspected deep vein thrombosis has a non-compressible popliteal vein with echogenic material and no flow on color Doppler. What is the most appropriate next step in reporting?

  1. Recommend repeat examination only if symptoms worsen
  2. Report as a normal variant of venous anatomy
  3. Report as chronic venous insufficiency
  4. Report as an acute occlusive deep vein thrombosis of the popliteal vein Correct answer.

Explanation

Absent compressibility with intraluminal echogenic material and no detectable flow indicates an occlusive thrombus in the popliteal vein. The finding requires prompt reporting so that anticoagulation can be considered.

Question 14Vascular Technology

Which of the following best describes the appearance of a normal carotid artery intima-media complex on grayscale imaging?

  1. A single echogenic line representing the intima only
  2. An irregular echogenic plaque protruding into the lumen
  3. A uniformly anechoic lumen without visible wall layers
  4. A double-line pattern with an echogenic intima and media separated by a hypoechoic layer Correct answer.

Explanation

The normal intima-media complex appears as two parallel echogenic lines with a hypoechoic space between them, representing the intima and media. Measurement of its thickness is used to assess subclinical atherosclerosis.

Question 15Vascular Technology

During a venous duplex study, a perforating vein shows bidirectional flow lasting 0.8 seconds after distal compression. How should this be interpreted?

  1. Normal perforator function
  2. Artifact from transducer pressure
  3. Acute perforator thrombosis
  4. Perforator incompetence Correct answer.

Explanation

Perforating vein reflux lasting more than about 0.5 seconds after distal compression indicates incompetence, which is associated with chronic venous ulceration. Normal perforators show brief, antegrade flow toward the deep system.

Question 16Vascular Technology

Which measurement is used to calculate the pulsatility index of a Doppler waveform?

  1. Mean velocity divided by peak systolic velocity
  2. The product of peak systolic velocity and vessel cross-sectional area
  3. The difference between peak systolic and end-diastolic velocity divided by mean velocity Correct answer.
  4. Peak systolic velocity divided by end-diastolic velocity

Explanation

The pulsatility index is (peak systolic velocity minus end-diastolic velocity) divided by the time-averaged mean velocity. It quantifies waveform pulsatility and is used in cerebrovascular and peripheral arterial assessment.

Question 17Vascular Technology

A patient with a cold, pulseless hand after cardiac catheterization undergoes duplex of the upper extremity. Which finding would most support an embolic occlusion of the brachial artery?

  1. A triphasic waveform in the radial artery
  2. A normal ulnar artery velocity with respiratory variation
  3. A focal filling defect with absent flow distal to the occlusion Correct answer.
  4. A dilated vein with spontaneous flow

Explanation

An embolic occlusion produces an abrupt cutoff of flow with a visible intraluminal defect at the site of impaction and absent or damped flow distally. Triphasic distal waveforms and normal velocities would argue against significant obstruction.

Question 18Vascular Technology

Which of the following is the most appropriate patient preparation before a renal artery duplex examination?

  1. Administration of intravenous contrast
  2. Fasting for 6 to 8 hours to reduce bowel gas Correct answer.
  3. Nothing by mouth for 12 hours
  4. Full bladder to improve acoustic windows

Explanation

Fasting for roughly 6 to 8 hours reduces bowel gas and improves visualization of the renal arteries. A full bladder is helpful for pelvic examinations but not for renal artery imaging, and contrast is not used in duplex.

Question 19Vascular Technology

A carotid duplex demonstrates a peak systolic velocity of 90 cm/s in the internal carotid artery with a normal waveform and no plaque. What is the most appropriate interpretation?

  1. A complete occlusion
  2. A normal internal carotid artery velocity Correct answer.
  3. An artifact requiring repeat examination
  4. A hemodynamically significant stenosis

Explanation

A peak systolic velocity of about 90 cm/s at the ICA origin falls within the normal range, generally below 125 cm/s. Normal spectral morphology and absence of plaque further support a normal study.

Question 20Vascular Technology

In a patient with suspected median arcuate ligament syndrome, which duplex finding is most characteristic?

  1. A uniformly dilated superior mesenteric artery
  2. Reversed flow in the portal vein
  3. A focal velocity increase in the celiac artery that varies with respiration Correct answer.
  4. A high-resistance waveform in the renal artery

Explanation

Median arcuate ligament syndrome produces focal celiac artery compression with elevated velocities that characteristically change with respiration, particularly increasing during expiration. The superior mesenteric artery and portal vein findings listed are unrelated.

Question 21Vascular Technology

Which finding on duplex ultrasound is most consistent with a pseudoaneurysm at a femoral puncture site?

  1. A uniformly dilated vein with continuous flow
  2. A focal anechoic collection with a narrow neck and to-and-fro flow in the neck Correct answer.
  3. A focal velocity increase within the native artery
  4. A non-compressible artery with echogenic thrombus

Explanation

A pseudoaneurysm appears as a focal collection adjacent to the artery with a narrow communicating neck showing to-and-fro flow on spectral Doppler. Color Doppler often demonstrates a yin-yang pattern within the sac.

Question 22Vascular Technology

Which parameter is most useful for estimating the severity of a lower extremity arterial stenosis on duplex when velocities are obtained proximal and distal to the lesion?

  1. The peak systolic velocity ratio between the stenosis and the adjacent normal segment Correct answer.
  2. The vessel diameter measured on grayscale
  3. The absolute peak systolic velocity at the stenosis
  4. The end-diastolic velocity in the contralateral limb

Explanation

The velocity ratio compares the peak systolic velocity at the stenosis with that in an adjacent normal segment, correcting for systemic factors such as cardiac output. Ratios above about 2.0 to 2.5 suggest significant stenosis, whereas absolute velocities vary with flow state.

Question 23Vascular Technology

What is the typical normal range for the resistive index in a renal interlobar artery?

  1. 0.2 to 0.3
  2. 0.8 to 0.9
  3. 0.5 to 0.7 Correct answer.
  4. 1.0 to 1.2

Explanation

Normal renal interlobar artery resistive indices generally range from about 0.5 to 0.7. Values above 0.8 may indicate increased parenchymal resistance from renal disease.

Question 24Vascular Technology

During a venous insufficiency study, the great saphenous vein shows reflux lasting 1.5 seconds after distal compression. How should this be classified?

  1. Pathologic reflux of the great saphenous vein Correct answer.
  2. Acute superficial thrombophlebitis
  3. Artifact from inadequate augmentation
  4. Normal valve function

Explanation

Reflux in the superficial veins lasting more than about 0.5 seconds is considered pathologic, so 1.5 seconds clearly indicates great saphenous vein incompetence. Normal superficial valves close within half a second.

Question 25Vascular Technology

Which of the following best explains why a high wall filter setting can obscure low-velocity venous flow?

  1. It narrows the sample volume
  2. It reduces the angle of insonation
  3. It removes low-frequency Doppler shifts that correspond to slow flow Correct answer.
  4. It increases the transmitted ultrasound frequency

Explanation

The wall filter rejects low-frequency Doppler signals arising from slow-moving blood and vessel wall motion. Setting it too high removes genuine low-velocity venous signals, which can mimic absent flow.

Question 26Vascular Technology

During a carotid duplex examination, a focal color flow alias is seen at the origin of the internal carotid artery. Which Doppler parameter should be optimized first to determine whether the alias represents true elevated velocity or an artifact of scale setting?

  1. Increase the color velocity scale above the expected peak velocity Correct answer.
  2. Lower the color scale to detect slow flow in the bulb
  3. Increase the wall filter to remove low-frequency signals
  4. Decrease the color box width to increase frame rate

Explanation

Color alias occurs when the true Doppler shift exceeds the Nyquist limit set by the color scale. Raising the scale above the expected peak velocity removes ambiguity, so any residual alias reflects genuine high velocity rather than a scale artifact. Narrowing the box or adjusting the filter does not resolve the aliasing itself.

Question 27Vascular Technology

Which duplex finding is the most reliable indicator of a hemodynamically significant stenosis at the superficial femoral artery?

  1. Peak systolic velocity ratio greater than 2.0 across the stenosis Correct answer.
  2. Presence of spectral broadening within the stenosis
  3. Loss of the triphasic waveform distal to the stenosis
  4. Increase in vessel diameter at the stenosis

Explanation

A focal peak systolic velocity increase with a velocity ratio of 2.0 or greater relative to the adjacent normal segment is the standard criterion for a hemodynamically significant stenosis. Spectral broadening and waveform changes downstream are supportive but less specific.

Question 28Vascular Technology

A patient with end-stage renal disease has a brachiocephalic arteriovenous fistula. Which duplex measurement best predicts impending access failure?

  1. Venous diameter of 6 mm at the outflow
  2. Access flow volume below 500 mL/min Correct answer.
  3. Resistive index in the feeding artery of 0.55
  4. Peak systolic velocity at the anastomosis of 150 cm/s

Explanation

Access flow below approximately 500 mL/min is a recognized threshold associated with increased risk of thrombosis and failure. Serial flow trends are more informative than a single velocity or diameter measurement.

Question 29Vascular Technology

Which physiologic principle explains why Doppler ultrasound can detect flow direction in a vessel?

  1. The Doppler shift is independent of the angle of insonation
  2. The Doppler shift is negative when flow moves toward the transducer
  3. The Doppler shift is always proportional to vessel diameter
  4. The Doppler shift is positive when flow moves toward the transducer Correct answer.

Explanation

The Doppler shift is positive when reflectors move toward the transducer and negative when they move away, which is the basis for directional color and spectral display. The magnitude depends on the cosine of the insonation angle.

Question 30Vascular Technology

On a spectral Doppler tracing, which measurement represents the peak diastolic velocity used to calculate the resistive index?

  1. The end-diastolic velocity at the trough of the waveform Correct answer.
  2. The mean velocity across the cardiac cycle
  3. The peak systolic velocity at the waveform apex
  4. The velocity at the dicrotic notch

Explanation

The resistive index is calculated as peak systolic velocity minus end-diastolic velocity divided by peak systolic velocity. The end-diastolic value is taken at the lowest point of the diastolic portion of the waveform.

Question 31Vascular Technology

A patient reports calf pain after walking two blocks that resolves with rest. The ankle-brachial index is 0.65, and duplex shows a focal velocity increase in the popliteal artery. Which interpretation is most appropriate?

  1. Acute arterial occlusion of the popliteal artery
  2. Moderate peripheral arterial disease with a focal stenosis consistent with claudication Correct answer.
  3. Normal study with nonvascular cause of pain
  4. Critical limb ischemia requiring immediate intervention

Explanation

An ABI of 0.65 falls in the moderate range and, combined with a focal velocity step-up and classic claudication symptoms, supports a hemodynamically significant stenosis. Critical limb ischemia typically presents with rest pain or tissue loss and lower indices.

Question 32Vascular Technology

Which sonographic finding is characteristic of a normal lower extremity vein during a compression maneuver?

  1. Dilation of the vein with loss of phasic flow
  2. Appearance of spontaneous echogenic thrombus
  3. Complete coaptation of the venous walls with obliteration of the lumen Correct answer.
  4. Partial reduction of the lumen with persistent echogenic flow

Explanation

Normal veins compress completely because their thin walls coapt when light pressure is applied. Failure to compress fully suggests thrombus or another intraluminal process.

Question 33Vascular Technology

During a renal artery duplex study, a peak systolic velocity of 220 cm/s is recorded in the main renal artery with a normal aortic velocity of 50 cm/s. What does the renal-aortic ratio indicate?

  1. A ratio of 4.4, suggesting a hemodynamically significant renal artery stenosis Correct answer.
  2. A ratio of 0.23, suggesting a normal renal artery
  3. A ratio of 1.0, suggesting no stenosis
  4. A ratio of 2.2, suggesting a borderline stenosis

Explanation

The renal-aortic ratio is calculated by dividing the renal peak systolic velocity by the aortic peak systolic velocity. A value of 220 divided by 50 equals 4.4, which exceeds the commonly used threshold of 3.5 for significant stenosis.

Question 34Vascular Technology

Which finding on a venous duplex study most directly supports the diagnosis of a recurrent deep vein thrombosis in a previously affected segment?

  1. A vein that fully compresses with augmentation of flow
  2. A constant-diameter hypoechoic lumen that does not compress and shows no flow Correct answer.
  3. A venous valve with a thin, mobile leaflet
  4. An echogenic band with partial compressibility and detectable flow

Explanation

Recurrent thrombosis typically appears as a non-compressible, hypoechoic lumen without flow, whereas chronic post-thrombotic change often shows echogenic, partially compressible material with flow. Distinguishing these patterns guides anticoagulation decisions.

Question 35Vascular Technology

What is the primary effect of increasing the Doppler sample volume length during arterial spectral acquisition?

  1. It widens the range of velocities sampled, potentially including flow from adjacent vessels Correct answer.
  2. It increases the transmitted frequency of the transducer
  3. It decreases the pulse repetition frequency automatically
  4. It eliminates spectral broadening from the waveform

Explanation

The sample volume length determines the axial extent over which velocities are detected. A longer gate can include flow from adjacent vessels or vessel wall motion, producing a broader, less specific spectrum.

Question 36Vascular Technology

Which vessel is typically identified as the first branch of the extracranial internal carotid artery and must be distinguished during carotid duplex?

  1. The ophthalmic artery Correct answer.
  2. The posterior communicating artery
  3. The middle cerebral artery
  4. The anterior choroidal artery

Explanation

The ophthalmic artery arises from the internal carotid artery and is an intracranial branch; however, among the listed options it is the vessel most commonly referenced when distinguishing internal carotid flow patterns. The middle cerebral and posterior communicating arteries are also intracranial branches but are not the first branch in the extracranial segment.

Question 37Vascular Technology

During a transcranial Doppler study, which parameter is most useful for assessing cerebral autoregulation in response to a CO2 challenge?

  1. Pulsatility index of the ophthalmic artery
  2. Percent change in mean flow velocity in the middle cerebral artery Correct answer.
  3. Resistive index of the vertebral artery
  4. Peak systolic velocity in the basilar artery

Explanation

Cerebrovascular reactivity is assessed by measuring the change in middle cerebral artery mean velocity during hypercapnia or hypocapnia. A preserved response indicates intact autoregulation.

Question 38Vascular Technology

Which duplex finding is most consistent with a normal hemodialysis access fistula?

  1. Flow reversal in the feeding artery during systole
  2. Low-resistance flow in the feeding artery with continuous flow in the outflow vein Correct answer.
  3. High-resistance flow in the feeding artery with pulsatile outflow
  4. Absent flow in the outflow vein at rest

Explanation

A functioning fistula creates a low-resistance circuit, producing high diastolic flow in the feeding artery and continuous, non-pulsatile flow in the draining vein. These features reflect adequate outflow and low resistance.

Question 39Vascular Technology

A patient with a suspected popliteal entrapment syndrome undergoes duplex with active plantar flexion. Which finding supports the diagnosis?

  1. Complete loss of triphasic flow in the dorsalis pedis at rest
  2. Increased venous reflux in the popliteal vein
  3. Focal acceleration of flow in the popliteal artery during provocation Correct answer.
  4. Dilation of the popliteal artery during provocation

Explanation

Popliteal entrapment produces dynamic compression of the popliteal artery during provocation, seen as focal velocity increase or occlusion. Resting studies may be normal, so provocative maneuvers are essential.

Question 40Vascular Technology

Which factor most limits the accuracy of duplex grading of an internal carotid artery stenosis when the vessel is heavily calcified?

  1. Acoustic shadowing obscuring the residual lumen and velocity sample Correct answer.
  2. Low cardiac output reducing systolic velocities
  3. Increased depth of the vessel from the skin surface
  4. Use of a linear array transducer

Explanation

Heavy calcification produces acoustic shadowing that obscures the lumen and prevents accurate placement of the Doppler gate. This can lead to underestimation or overestimation of stenosis severity.

Question 41Vascular Technology

What is the expected normal direction of flow in the vertebral artery relative to the common carotid artery?

  1. Same direction as the common carotid, toward the brain Correct answer.
  2. Absent at rest with flow only during exercise
  3. Bidirectional throughout the cardiac cycle
  4. Opposite direction to the common carotid, away from the brain

Explanation

In a normal vertebral artery, flow proceeds cranially, in the same direction as the common carotid artery. Reversal of vertebral flow suggests subclavian steal physiology.

Question 42Vascular Technology

Which measurement is most appropriate for documenting the severity of a venous valve incompetence in the great saphenous vein?

  1. Resistive index of the common femoral artery
  2. Vessel diameter at the saphenofemoral junction
  3. Peak systolic velocity during augmentation
  4. Duration of retrograde flow after distal augmentation Correct answer.

Explanation

Reflux duration after distal compression or Valsalva is the standard criterion for venous incompetence. Thresholds of approximately 0.5 seconds for superficial veins and 1 second for deep veins are commonly applied.

Question 43Vascular Technology

A patient has a pulsatile mass at the groin after catheterization. Duplex shows a neck connecting the mass to the common femoral artery with a yin-yang color pattern. What is the diagnosis?

  1. Hematoma without vascular connection
  2. Pseudoaneurysm Correct answer.
  3. Femoral artery stenosis
  4. Arteriovenous fistula

Explanation

A pseudoaneurysm appears as a sac communicating with the artery through a neck, with swirling to-and-fro flow producing a yin-yang color pattern. An arteriovenous fistula would show high-velocity flow and venous arterialization.

Question 44Vascular Technology

Which parameter is used to calculate the pulsatility index of a Doppler waveform?

  1. Peak systolic velocity plus end-diastolic velocity divided by mean velocity
  2. End-diastolic velocity divided by peak systolic velocity
  3. Mean velocity divided by peak systolic velocity
  4. Peak systolic velocity minus end-diastolic velocity divided by mean velocity Correct answer.

Explanation

The pulsatility index equals the difference between peak systolic and end-diastolic velocity divided by the time-averaged mean velocity. It reflects downstream resistance and waveform pulsatility.

Question 45Vascular Technology

During an upper extremity venous study, a patient's arm is cold and the technologist notes sluggish flow. Which maneuver best improves venous filling for evaluation?

  1. Warming the limb and performing distal augmentation Correct answer.
  2. Increasing the wall filter to maximum
  3. Elevating the limb above the heart for the entire study
  4. Applying proximal compression during imaging

Explanation

Cold extremities cause vasoconstriction and sluggish venous flow. Warming the limb and using distal augmentation improve venous filling and detectability.

Question 46Vascular Technology

Which duplex characteristic most reliably distinguishes a carotid body tumor from a cervical lymph node?

  1. Splaying of the internal and external carotid arteries with intense vascularity Correct answer.
  2. Complete compressibility with a hypoechoic center
  3. Homogeneous echogenicity with a thin capsule
  4. Posterior acoustic enhancement without internal flow

Explanation

Carotid body tumors classically splay the internal and external carotid arteries and are highly vascular. Lymph nodes typically do not splay the carotid bifurcation.

Question 47Vascular Technology

Which factor most affects the accuracy of a peak systolic velocity measurement when the angle of insonation is not corrected?

  1. The pulse repetition frequency
  2. The transducer footprint size
  3. The cosine of the angle between the beam and the vessel Correct answer.
  4. The display color map

Explanation

Velocity is calculated from the Doppler shift using the cosine of the angle between the ultrasound beam and the direction of flow. An uncorrected or incorrect angle introduces systematic error.

Question 48Vascular Technology

A patient with suspected median arcuate ligament syndrome has a celiac artery peak systolic velocity that increases markedly during expiration. Which interpretation is most appropriate?

  1. Fixed atherosclerotic celiac stenosis
  2. Superior mesenteric artery occlusion
  3. Dynamic celiac artery compression consistent with the syndrome Correct answer.
  4. Normal variant without clinical significance

Explanation

Median arcuate ligament syndrome produces dynamic compression of the celiac artery that worsens with expiration and improves with inspiration. This respiratory variation distinguishes it from fixed atherosclerotic stenosis.

Question 49Vascular Technology

Which finding on duplex of a lower extremity artery suggests a hemodynamically significant stenosis rather than a normal bifurcation?

  1. Uniform velocity across the vessel with a clean spectral window
  2. Loss of diastolic flow only during exercise
  3. Focal velocity increase with spectral broadening and post-stenotic turbulence Correct answer.
  4. Symmetric triphasic waveforms proximal and distal to the site

Explanation

A significant stenosis produces a focal velocity increase, spectral broadening, and turbulence downstream. Normal bifurcations may show mild velocity change but not marked turbulence.

Question 50Vascular Technology

A carotid duplex shows a peak systolic velocity of 250 cm/s in the internal carotid artery with an end-diastolic velocity of 100 cm/s and visible plaque. Which stenosis category is most consistent with these findings?

  1. Mild stenosis of less than 50 percent
  2. Complete occlusion
  3. Severe stenosis of 70 percent or greater Correct answer.
  4. Normal internal carotid artery

Explanation

A peak systolic velocity above approximately 230 cm/s with an elevated end-diastolic velocity and visible plaque is consistent with a severe stenosis of 70 percent or greater. Complete occlusion would show no flow.