RPVI key terms

The highest blood flow speed recorded during systole at a given sample site, measured in cm/s by spectral Doppler and used as the primary criterion for grading arterial stenoses.

Widening or filling-in of the normally narrow Doppler waveform envelope, reflecting a range of red cell velocities at the sample site and suggesting disturbed, post-stenotic, or turbulent flow.

The peak systolic velocity at a stenosis divided by the peak systolic velocity in a normal segment proximal to it; ratios above roughly 3 to 4 suggest a hemodynamically significant narrowing.

The percentage by which a vessel lumen narrows at a plaque or lesion, estimated from B-mode and color images and correlated with velocity criteria to classify stenosis severity.

The appearance of atherosclerotic plaque on grayscale imaging, described by echogenicity, surface regularity, and homogeneity; ulcerated or hypoechoic plaque may carry higher embolic risk independent of degree of narrowing.

The combined thickness of the intimal and medial layers measured on a longitudinal B-mode image of the arterial wall, typically at the distal common carotid; increased thickness signals early atherosclerosis.

Chaotic, multidirectional flow seen distal to a significant stenosis or within a dilated segment, shown on color Doppler as mixed pixel colors and on spectral Doppler as a broad, ragged waveform.

The altered flow pattern immediately beyond a narrowing, characterized by lower velocity, spectral broadening, and sometimes flow reversal or a tardus-parvus appearance downstream.

A dampened spectral waveform with a slow systolic upstroke and low peak velocity, seen distal to a hemodynamically significant stenosis or occlusion with collateral supply.

The angle between the ultrasound beam and the direction of blood flow; velocities are most accurate when the angle is 60 degrees or less, and cosine correction is applied to the measured frequency shift.

Ambiguous color or spectral display that occurs when blood velocities exceed the Nyquist limit, appearing as color wrap-around or a waveform cut off at the edge of the scale; corrected by raising the scale or shifting the baseline.

A real-time display that maps mean blood velocity and direction onto grayscale anatomy using a color scale, helping localize vessels and identify areas of disturbed or absent flow.

A Doppler mode that displays the amplitude rather than the direction of the Doppler signal, giving greater sensitivity to slow flow and small vessels but no velocity or directional information.

A calculated value, (peak systolic velocity minus end-diastolic velocity) divided by peak systolic velocity, that describes downstream resistance; higher values indicate greater resistance in the vascular bed.

A calculated measure of waveform pulsatility, equal to the difference between peak systolic and end-diastolic velocity divided by mean velocity, reflecting the compliance and resistance of the perfused bed.

Interpretation of the shape, upstroke, and diastolic components of a spectral tracing to infer upstream and downstream hemodynamics, including resistance, stenosis, and collateral pathways.

The branch of the common carotid supplying the cerebral hemisphere; normally low-resistance with continuous diastolic flow, and the usual site of atherosclerotic stenosis evaluated in carotid duplex.

The vessel arising from the aortic arch or brachiocephalic trunk that bifurcates into the internal and external carotid arteries; its waveform reflects the combined downstream beds.

The branch of the common carotid supplying the face and scalp; typically higher resistance with little diastolic flow and often identifiable by its facial and temporal branches.

A maneuver in which the superficial temporal artery is tapped while recording a carotid waveform; oscillations appear in the external carotid branch and help distinguish ECA from ICA.

Symptoms such as dizziness, diplopia, or ataxia arising from reduced blood flow through the vertebral or basilar arteries, often evaluated with duplex and indirect physiologic testing.

The paired vessel arising from the subclavian arteries and ascending through the cervical spine to join the basilar artery; assessed for flow direction, patency, and stenosis in cerebrovascular exams.

Retrograde flow in a vertebral artery caused by proximal subclavian artery stenosis or occlusion, producing an arm-to-brain shunt; detected as reversed vertebral flow on duplex.

An indirect physiologic test that records pressure-related changes from the eye to assess carotid artery perfusion and estimate ophthalmic systolic pressure.

Combined B-mode, color, and spectral Doppler examination of the carotid and vertebral arteries used to detect plaque, grade stenosis, and characterize flow patterns.

The ratio of the highest ankle systolic pressure to the higher of the two brachial systolic pressures; values below about 0.90 suggest peripheral arterial disease.

Systolic blood pressure measurements taken with cuffs at multiple levels of the limb to localize hemodynamically significant arterial disease by pressure gradients between adjacent segments.

A plethysmographic technique that records volume changes in a limb segment with each cardiac cycle, producing a waveform whose amplitude and contour indicate proximal arterial obstruction.

An optical technique using infrared light to detect pulsatile changes in skin blood volume, commonly used for digital waveforms, toe pressures, and venous reflux assessment.

The ratio of toe systolic pressure to brachial systolic pressure, useful when ankle pressures are falsely elevated by medial calcinosis; a normal value is roughly 0.70 or greater.

Treadmill or active pedal plantarflexion exercise followed by repeat ankle pressures, used to unmask hemodynamically significant disease when resting indices are normal or borderline.

Normal multiphasic arterial spectral patterns with sharp systolic peaks and one or more diastolic components; loss of these phases suggests proximal stenosis or increased downstream resistance.

A dampened arterial spectral tracing with a single broad systolic peak and no reverse flow component, indicating significant proximal obstruction or a low-resistance distal bed.

A contained rupture of an artery in which blood communicates with a surrounding hematoma through a narrow neck, showing a yin-yang color pattern and a to-and-fro spectral signal at the neck.

An abnormal direct connection between an artery and a vein, producing high-velocity turbulent flow, arterialized venous pulsatility, and often a palpable thrill or audible bruit.

Retrograde flow through a venous valve that fails to close, detected by duplex as reversed flow lasting longer than about 0.5 to 1 second after distal augmentation or Valsalva.

Clot within a deep vein, identified on duplex by noncompressibility, intraluminal echogenicity, absent or reduced spontaneous flow, and loss of phasicity with respiration.

The primary technique for evaluating deep veins, in which graded transducer pressure is applied to assess whether the vein collapses completely; noncompressibility suggests thrombus.

The normal variation of venous flow with respiration, reflecting changes in intrathoracic and intra-abdominal pressure; loss of phasicity may indicate proximal obstruction.

A transient increase in venous flow produced by squeezing the limb distal to the sample site; a normal brisk response confirms patency between the two points and helps assess valvular competence.

A vein connecting the superficial and deep venous systems through the fascia; incompetence produces outward flow during muscle contraction and can contribute to chronic venous insufficiency.

A syndrome of sustained venous hypertension from valve failure or obstruction, producing edema, skin changes, and ulceration, supported by reflux or obstruction on duplex.

Doppler evaluation of the renal arteries and kidneys to detect stenosis or occlusion, using elevated peak systolic velocity and a tardus-parvus intrarenal waveform as key indicators.

Compression of the celiac artery by the median arcuate ligament of the diaphragm, causing a focal hook-like narrowing with elevated velocities that may vary with respiration.

Doppler assessment of the celiac trunk and superior mesenteric artery for stenosis, aneurysm, or compression, using velocity thresholds and waveform characteristics.

Elevated pressure in the portal venous system, often from cirrhosis, shown on ultrasound by enlarged portal vein, reduced or reversed flow, splenomegaly, and portosystemic collaterals.

The large vessel carrying blood from the splanchnic bed to the liver; assessed for diameter, patency, flow direction, and thrombosis, especially before liver transplantation.

The artery supplying the liver and biliary tree, evaluated after transplantation for patency, resistive index, and signs of stenosis or thrombosis.

Development of alternative blood flow pathways around an occlusion or high-grade stenosis, which can restore distal perfusion and alter the expected pressure and waveform findings.