Free RVT Exam Flashcards

The ICA normally has a low-resistance pattern with forward diastolic flow because it supplies the brain. Compare it with the ECA, which is usually more pulsatile and higher resistance.

The ECA has cervical branches and a higher-resistance waveform. Temporal tapping may create oscillations in the ECA tracing, helping distinguish it from the ICA during duplex.

Avoid excessive pressure at the carotid bifurcation because the sinus contains pressure-sensitive receptors. Compression can trigger a vagal response in susceptible patients.

Normal vertebral flow is antegrade toward the brain. Reversal or bidirectional flow suggests a proximal subclavian problem and should prompt careful correlation with arm pressures and symptoms.

A proximal subclavian obstruction can pull blood away from the vertebrobasilar system toward the arm. Duplex may show progressively abnormal vertebral flow, from early systolic deceleration to complete reversal.

Spectral broadening means a wide range of Doppler shifts are present. It commonly appears with disturbed flow, turbulence, poor sample placement, or excessive gain.

Aliasing occurs when the Doppler shift exceeds the system's sampling limit. Raising the scale, lowering the baseline, reducing Doppler frequency, or using continuous wave Doppler can help display high velocities.

Velocity estimates are most defensible when the Doppler cursor is aligned with flow and the angle is 60 degrees or less. Incorrect angle alignment can make a normal vessel look falsely abnormal.

Set the color scale to match expected flow. Too low a scale creates aliasing and color noise; too high a scale can hide slow flow, especially in veins or distal arteries.

Power Doppler is sensitive to low-volume flow and less angle dependent than color direction mapping. It does not show direction well, so it should not replace spectral confirmation when direction matters.

Laminar flow moves in organized layers, with faster flow near the center of the vessel and slower flow near the wall. Normal laminar flow produces a clean spectral window.

Turbulence appears as chaotic flow with spectral fill-in, color variance, vibration, or bruit. It often occurs distal to a significant narrowing or at abrupt changes in vessel geometry.

When flow volume is conserved through a narrowed segment, velocity rises inside the narrowed lumen. This is why focal velocity acceleration is a core clue for stenosis.

Downstream from a severe stenosis, the waveform may become damped with delayed systolic rise and reduced pulsatility. This supports a proximal hemodynamic lesion even when the lesion itself is hard to see.

Peripheral limb arteries normally show higher resistance at rest, while arteries supplying low-resistance beds show more continuous diastolic flow. Always interpret waveform shape in its vascular territory.

Typical arch branching is brachiocephalic artery, left common carotid artery, and left subclavian artery. The brachiocephalic then divides to supply the right carotid and right subclavian systems.

The common carotid artery divides into the ICA and ECA. The ICA supplies the brain and has no neck branches; the ECA supplies face and scalp structures through multiple branches.

The superficial femoral artery continues through the adductor hiatus and becomes the popliteal artery. This transition matters when tracing lower extremity arterial disease.

Below the knee, runoff assessment follows the anterior tibial, posterior tibial, and peroneal arteries. Knowing their course helps distinguish true occlusion from incomplete scanning.

The great saphenous vein travels along the medial leg and thigh to the saphenofemoral junction. It is a major target in reflux exams and a common conduit for bypass grafting.

The small saphenous vein ascends the posterior calf and commonly joins the popliteal vein. Its termination varies, so duplex should follow the actual anatomy rather than assume a single pattern.

The celiac axis typically supplies the liver, stomach, and spleen through hepatic, left gastric, and splenic branches. Variant anatomy is common and should be documented when seen.

A normal mesenteric artery supplying bowel can show increased diastolic flow after a meal because vascular resistance falls during digestion. Fasting status helps explain waveform differences.

A focal renal artery stenosis is suggested by localized velocity acceleration, turbulence, and downstream waveform delay. Compare both kidneys and correlate with aortic flow and technical limitations.

A complete aneurysm exam documents maximal diameter, extent, thrombus, lumen flow, branch involvement when visible, and relationship to prior repair if present.

Normal portal venous flow is hepatopetal, meaning toward the liver. Direction, pulsatility, and patency should be described because they can change with liver and cardiac disease.

A hemodynamically important arterial stenosis usually produces focal velocity increase, color aliasing, turbulence, and waveform change beyond the lesion. Diagnosis should use the full pattern, not a single image.

Occlusion is suggested by absent color and spectral flow in the vessel segment, collateral flow around it, and reconstitution distally. Confirm with optimized settings before calling no flow.

A pseudoaneurysm communicates with an artery through a neck. Duplex often shows bidirectional flow in the neck and swirling flow in the sac, which guides treatment planning.

An acquired AV fistula creates direct arterial-to-venous communication. Expect arterialized venous flow, low-resistance arterial inflow, vibration, and localized color turbulence.

Acute venous thrombus is often more distending and less echogenic; chronic thrombus is more likely contracted, echogenic, and associated with wall thickening or collateral channels.

Failure of a vein to compress is a primary sign of thrombus. Compression should be performed carefully, compared segment by segment, and supplemented with color and spectral findings.

Normal lower extremity venous Doppler varies with breathing. Loss of expected phasicity can suggest proximal obstruction, extrinsic compression, or technical factors that need investigation.

Manual distal compression should increase venous flow if the pathway is patent. A poor response can reflect obstruction, poor technique, patient guarding, or inadequate distal compression.

Reflux exams test valve competence by provoking reverse flow with maneuvers such as distal compression-release or Valsalva at junctions. The report should identify the segment and source of reflux.

Perforators connect superficial and deep venous systems. Incompetent perforators can feed varicosities and ulcers, so reflux exams should map clinically relevant connections.

The ankle-brachial index compares ankle systolic pressure with brachial systolic pressure. Use it as a physiologic screen for lower extremity arterial disease and interpret it with waveform quality.

When ankle vessels do not compress well, ABI can look falsely reassuring. Toe pressures, PPG, Doppler waveforms, and clinical context can better reflect distal perfusion.

Segmental pressures localize arterial disease by comparing pressure changes between limb levels. A meaningful drop points to disease between the two measurement sites.

PVR waveforms assess limb volume change with each pulse. Dampened amplitude, delayed upstroke, or flattened contours support impaired arterial inflow even when pressures are hard to obtain.

Exercise testing can reveal flow limitation that is not obvious at rest. Post-exercise pressure and waveform recovery help distinguish vascular claudication from nonvascular leg pain.

Graft evaluation follows inflow, proximal anastomosis, conduit, distal anastomosis, and outflow. Focal velocity changes, low graft flow, or new waveform dampening may signal graft-threatening disease.

Stents can create artifact and alter compliance, so assess the pre-stent segment, entire stent, edges, and downstream flow. Compare with prior studies when available.

An AV access exam checks arterial inflow, anastomosis, draining vein or graft, depth, diameter, stenosis, thrombus, and complications such as steal or pseudoaneurysm.

Post-EVAR ultrasound evaluates sac size, graft patency, limb flow, and evidence of endoleak. Comparison with prior imaging is essential because change over time drives concern.

For vascular access, identify the vessel, confirm patency, avoid adjacent nerves or arteries, maintain sterile technique, and keep the needle tip visible whenever possible.

Compression treatment requires confirmation of anatomy, attention to anticoagulation status, patient tolerance, and distal perfusion. Stop and escalate if pain, ischemic signs, or instability develops.

Use the lowest output and shortest exposure that produces diagnostic information. This is especially important during long exams, repeated measurements, and guided procedures.

A defensible report documents indication, vessels evaluated, technical limits, representative images, Doppler measurements, waveform descriptors, and clinically important positive or negative findings.

If anatomy, symptoms, grayscale, color, and spectral data disagree, optimize settings and rescan before concluding. Vascular interpretation depends on a coherent pattern across modalities.