AJR 2003; 181:1695-1704
© American Roentgen Ray Society
A Spectrum of Doppler Waveforms in the Carotid and Vertebral Arteries
Eric M. Rohren1,
Mark A. Kliewer2,
Barbara A. Carroll3 and
Barbara S. Hertzberg3
1 Mayo Clinic, 200 1st St., SW, Rochester, MN 55905.
2 Department of Radiology, University of Wisconsin, E3/311, 600 Highland Ave.,
Madison, WI 53792-3252.
3 Department of Radiology, Duke University Medical Center, Rm. 2526 Blue Zone,
Box 3808, Durham, NC 27710.
Received March 2, 2001;
accepted after revision April 28, 2003.
Address correspondence to M. A. Kliewer.
Introduction
The central focus of carotid Doppler sonography studies is the detection
and characterization of atherosclerotic disease and stenosis. Doppler
sonography samples are used primarily to quantify velocity elevations at sites
of stenosis. However, more subtle clues to disease are contained in the shape
and contour of the Doppler sonography waveform itself. Aberrations of waveform
morphology can signal regional disease in the carotid and vertebral vessels,
remote cardiovascular disease, and iatrogenic conditions.
Typical Carotid and Vertebral Artery Waveforms
Although slightly variable in appearance from patient to patient, the
spectral waveforms of the common, external, and internal carotid arteries and
the vertebral artery largely reflect the character of the vascular bed being
supplied (Fig. 1A,
1B,
1C,
1D). Departure from these
prototypic waveforms requires explanation.
View larger version (96K):
[in this window]
[in a new window]
[as a PowerPoint slide]
|
Fig. 1A. —76-year-old asymptomatic man with normal carotid and
vertebral spectral tracings. Doppler sonogram shows normal internal carotid
artery that supplies low-resistance vascular bed of brain and therefore has
low-resistance waveform. Note sharp rise in flow velocity during systole and
gradual tapering of continuously forward flow throughout diastole. Internal
carotid artery waveform tends to display more blunted systolic peak and
greater diastolic flow than is seen in external carotid artery waveform.
|
|
View larger version (97K):
[in this window]
[in a new window]
[as a PowerPoint slide]
|
Fig. 1B. —76-year-old asymptomatic man with normal carotid and
vertebral spectral tracings. Doppler sonogram shows external carotid artery
that supplies high-resistance vascular beds of osseous and muscular structures
of head and neck; thus, waveform is characterized by sharp rise in flow
velocity during systole, rapid decline toward baseline, and diminished
diastolic flow. Transient reversal in early diastole can be seen normally.
|
|
View larger version (81K):
[in this window]
[in a new window]
[as a PowerPoint slide]
|
Fig. 1C. —76-year-old asymptomatic man with normal carotid and
vertebral spectral tracings. Doppler sonography waveform of common carotid
artery represents amalgamation of flow profiles of internal carotid artery and
external carotid artery. Normally, common carotid artery waveform assumes
relatively low resistance character because of preponderance of carotid flow
entering internal carotid artery ( 80%). Occasionally, transient flow
reversal may be seen in healthy people. Peak systolic velocities in common
carotid artery can be high in young patients with compliant vessels; such
velocities tend to decrease with age.
|
|
View larger version (85K):
[in this window]
[in a new window]
[as a PowerPoint slide]
|
Fig. 1D. —76-year-old asymptomatic man with normal carotid and
vertebral spectral tracings. Doppler sonogram shows normal vertebral artery
waveforms that resemble those of internal carotid artery, because vertebral
artery also supplies low-resistance vascular bed of brain. Typical vertebral
artery waveform is low resistance with continuous forward flow during
diastole.
|
|
Waveform Changes in Systole
Pulsus Parvus and Pulsus Tardus
Diminished and delayed arterial pulsations have been termed pulsus parvus
and pulsus tardus [1]
(Fig. 2). During carotid
Doppler sonography, the parvus–tardus waveform is characterized by a
small, smooth, and rounded systolic peak and is observed distal to severe
atherosclerotic stenoses in approximately 91% of cases
[1]. When bilateral
parvus–tardus waveforms are encountered, central causes of obstruction
should be suspected, including aortic valvular or central arterial
stenosis.
View larger version (102K):
[in this window]
[in a new window]
[as a PowerPoint slide]
|
Fig. 2. —66-year-old woman with high-grade atherosclerotic stenosis of
proximal right internal carotid artery and parvus–tardus waveforms in
mid internal carotid artery. Spectral Doppler sonography tracings distal to
stenosis show diminished peak systolic amplitude (pulsus parvus) and prolonged
systolic acceleration evident in delayed systolic upstroke and rounded
systolic peak (pulsus tardus). This waveform most often results from
high-grade stenosis, which may occur anywhere from aortic valve to carotid
arteries. If stenosis is central, such as aortic valvular disease,
parvus–tardus waveforms are often identified within both carotid
arteries.
|
|
Pulsus Bisferiens
Two prominent systolic peaks with an interposed mid systolic retraction are
termed pulsus bisferiens [2],
which is Latin for "beat twice"
(Fig. 3). This waveform is seen
in approximately 50% of patients with aortic valvular disease and is also
found with hypertrophic obstructive cardiomyopathy
[2]. The presence of
concomitant aortic stenosis and aortic insufficiency magnifies the bisferiens
effect.
View larger version (98K):
[in this window]
[in a new window]
[as a PowerPoint slide]
|
Fig. 3. —78-year-old woman with severely stenotic aortic valve
complicated by aortic regurgitation. Doppler sonography waveforms from
arteries (right common carotid artery is shown as example) show bisferious
pulse, with prominent mid systolic retraction (arrow) distinct from
dicrotic notch (arrowhead). Dicrotic notch is normal finding and is
because of closure of aortic valve, temporary cessation of forward flow,
followed by resumption of forward flow driven by elastic rebound of aortic
wall. Mechanism of pulsus bisferiens in aortic insufficiency is not well
understood. One view is that first peak represents initial high-volume
ejection of blood, which is followed by abrupt mid systolic flow deceleration
caused by regurgitant valve, and second peak represents tidal wave reflected
from distended aorta as it relaxes or from periphery of body. Others argue
that rapid ejection of large volume of blood (increased preload of left
ventricle) creates transient suction (Venturi) effect in aorta, which in turn
produces mid systolic retraction in carotid artery waveform.
|
|
Pulsus Alternans
Pulsus alternans denotes alternating peak systolic heights with a regular
cardiac rhythm (Fig. 4).
Intrinsic myocardial disease (ischemia, cardiomyopathy, or valvular heart
disease), metabolic disease (hypocalcemia), or impairment of venous return
(inferior vena cava compression or obstruction) can produce this waveform
[3]. The sensitivity of the
finding is unknown.
View larger version (97K):
[in this window]
[in a new window]
[as a PowerPoint slide]
|
Fig. 4. —47-year-old man with pulsus alternans caused by idiopathic
dilated cardiomyopathy. Doppler sonogram shows peak systolic velocities in
external carotid artery that oscillate between two levels on sequential beats
(arrows). Note that cardiac rhythm remains regular throughout.
|
|
Presteal Waveforms
Spectral waveforms in the vertebral arteries will occasionally assume an
appearance popularly referred to as the "bunny" waveform (Fig.
5A,
5B). The depth of mid systolic
velocity decline correlates to the degree of subclavian arterial stenosis in
all cases of one series [4].
Provocative maneuvers can convert a presteal waveform to a complete steal
(Fig. 6A,
6B). It is postulated that the
subclavian stenosis creates a high-velocity jet of blood directed across the
origin of the left vertebral artery during systole, causing a transient
pressure drop in the vertebral artery and concomitant decline in flow in mid
systole because of the Venturi effect. Although more commonly seen in the
vertebral vessels, these presteal waveforms also appear in the right carotid
artery and are produced by an analogous mechanism
(Fig. 7).
View larger version (88K):
[in this window]
[in a new window]
[as a PowerPoint slide]
|
Fig. 5A. —54-year-old woman with asymptomatic left subclavian stenosis
and presteal waveforms in vertebral artery. Doppler sonogram shows midsystolic
velocity deceleration (arrow) present in left vertebral artery
(VERT). Note echocardiogram tracing indicating beginning of systole at QRS
complex (arrowhead).
|
|
View larger version (6K):
[in this window]
[in a new window]
[as a PowerPoint slide]
|
Fig. 5B. —54-year-old woman with asymptomatic left subclavian stenosis
and presteal waveforms in vertebral artery. Drawing shows contour of spectral
tracing in presteal states that has been fancifully compared to rabbit in
profile. Making this imaginative leap facilitates recognition of otherwise
complex waveform pattern.
|
|
View larger version (84K):
[in this window]
[in a new window]
[as a PowerPoint slide]
|
Fig. 6A. —83-year-old woman with known atherosclerotic disease of left
subclavian artery. Doppler sonogram shows conversion of presteal waveform to
complete vertebral steal. Spectral tracings from left vertebral artery show
waveform characterized by pronounced mid systolic cleft (arrow) and
transient reversal of flow during systole. This wave pattern indicates
bidirectional flow, represented above and below baseline. This transient
reversal represents progression of mid systolic cleft noted in early presteal
waveform illustrated in Figure
5A,
5B. Note that flow in artery is
antegrade for most of cardiac cycle.
|
|
View larger version (69K):
[in this window]
[in a new window]
[as a PowerPoint slide]
|
Fig. 6B. —83-year-old woman with known atherosclerotic disease of left
subclavian artery. Doppler sonogram shows that when blood pressure cuff is
inflated on left arm, then rapidly deflated, there is conversion of waveform
in left vertebral artery from presteal pattern to complete steal pattern, in
which there is total reversal of flow throughout cardiac cycle. Blood pressure
cuff maneuver induces reactive hyperemia in arm and increases blood flow
across subclavian stenosis. Higher velocities within subclavian artery result
in complementary drop in pressure and redirection of blood flow in ipsilateral
vertebral artery toward its now-lower-pressure subclavian origin.
|
|
View larger version (92K):
[in this window]
[in a new window]
[as a PowerPoint slide]
|
Fig. 7. —Presteal Doppler sonography waveform appearance in right
external carotid artery of 54-year-old man with atherosclerotic disease of
right brachiocephalic artery. Spectral tracings from right external carotid
artery show waveform similar in appearance to presteal waveforms described in
vertebral arteries (Fig. 5A,
5B). Doppler sonography
tracings from left carotid artery were normal. Stenosis of brachiocephalic
artery is thought to cause jet of flow across origin of right common carotid
artery, leading to transient drop in pressure at peak systole. Mid systolic
retraction is evident in Doppler sonography waveforms.
|
|
Waveform Changes in Diastole
Internalization of the External Carotid Artery
The conversion to a low-resistance Doppler sonography waveform in the
external carotid artery has been termed "internalization" because
the abnormal spectral tracings in the external carotid artery mimic the
spectral tracings in a healthy internal carotid artery
[5]. This change is often
because of complete occlusion of the internal carotid artery with subsequent
development of low-resistance collateral pathways between the ipsilateral
external and internal circulations (Fig.
8), usually through the ophthalmic bed
[6] or between contralateral
external circulations through a superficial vascular network
[7] (Fig.
9A,
9B).
View larger version (86K):
[in this window]
[in a new window]
[as a PowerPoint slide]
|
Fig. 8. —73-year-old woman with internalization of left external
carotid artery because of complete occlusion of left internal carotid artery.
Doppler sonogram shows that external carotid artery waveform has assumed
contour similar to that of healthy internal carotid artery, with increased
diastolic flow. Most often, collateral blood supply to intracranial arteries
from external carotid system traverses ophthalmic bed.
|
|
View larger version (65K):
[in this window]
[in a new window]
[as a PowerPoint slide]
|
Fig. 9A. —78-year-old man with retrograde flow in left external carotid
artery caused by complete occlusion of left common carotid artery. Spectral
Doppler sonography tracing from left external carotid artery shows blood flow
directed toward transducer (note positive velocities on scale). Therefore,
flow in external carotid artery is retrograde toward carotid bulb and then
antegrade in internal carotid artery.
|
|
View larger version (73K):
[in this window]
[in a new window]
[as a PowerPoint slide]
|
Fig. 9B. —78-year-old man with retrograde flow in left external carotid
artery caused by complete occlusion of left common carotid artery. Spectral
Doppler sonography tracing from internal carotid artery shows flow away from
transducer (display has been inverted to show waveform above baseline; note
negative velocity measurements on scale). Therefore, flow in internal carotid
artery is antegrade, reconstituted via retrograde flow in external carotid
artery. Note that reconstituted flow in external carotid artery and internal
carotid artery displays low-resistance waveform with diminished systolic
amplitude and delayed systolic upstroke similar to parvus–tardus
waveform. This waveform is seen in 70% of proximal occlusions, presumably
resulting from filtering out of higher frequency velocities by collateral
network supplying external carotid artery, often from contralateral external
carotid artery system.
|
|
Water-Hammer Pulse
Normal or elevated peak systolic velocity followed by a precipitous decline
and reversal of flow during diastole is often seen with severe, isolated
aortic valvular regurgitation (Fig.
10), mirroring the findings on physical examination.
View larger version (92K):
[in this window]
[in a new window]
[as a PowerPoint slide]
|
Fig. 10. —Water-hammer spectral appearance on sonography of 83-year-old
man with severe aortic regurgitation. Spectral Doppler sonography tracing from
proximal right common carotid artery shows widened pulse pressure signaled by
sharp systolic peak, precipitous deceleration of flow in late systole, and
sustained reversal of flow through diastole. The spectral waveforms mirror
physical examination finding of water-hammer pulses in patients with severe
aortic regurgitation.
|
|
To-and-Fro Flow
In the neck of pseudoaneurysms, blood flows toward the pseudoaneurysm in
systole and returns to the parent artery in diastole. These alternating
currents can be reflected in the lumen of a parent artery and detected on
spectral Doppler sonography (Fig.
11A,
11B). Pseudoaneurysms of the
carotid arteries occur as a consequence of trauma, surgery, or misplaced
central venous lines.
View larger version (116K):
[in this window]
[in a new window]
[as a PowerPoint slide]
|
Fig. 11A. —45-year-old man with history of central venous line
inadvertently placed in artery. Color Doppler sonogram shows large
pseudoaneurysm (arrows) with swirling flow in patient's neck. Further
examination revealed neck of pseudoaneurysm arises from mid common carotid
artery (not shown).
|
|
View larger version (74K):
[in this window]
[in a new window]
[as a PowerPoint slide]
|
Fig. 11B. —45-year-old man with history of central venous line
inadvertently placed in artery. Proximal to pseudoaneurysm, Doppler sonogram
shows pulse contour in common carotid artery (CCA) is irregular and jagged,
and there is reversal of flow in diastole (arrow), resembling
to-and-fro pattern produced by exchanging currents in pseudoaneurysm neck.
|
|
Shunt Vascularity
High-flow and low-resistance waveforms with nearly uninterrupted forward
flow are seen in cases of vascular shunting caused by arteriovenous shunting
(Fig. 12A,
12B,
12C). There is coexisting
pulsatility of venous waveforms and often a soft-tissue bruit, which is the
color speckling at the site of the fistula caused by tissue reverberation from
the adjacent highly turbulent flow.
View larger version (92K):
[in this window]
[in a new window]
[as a PowerPoint slide]
|
Fig. 12A. —19-year-old man who sustained gunshot injury to neck. Doppler
sonography waveforms in right vertebral artery show extremely high flow
velocities during both peak systole and diastole, indicating shunt of arterial
flow into low pressure system.
|
|
View larger version (148K):
[in this window]
[in a new window]
[as a PowerPoint slide]
|
Fig. 12C. —19-year-old man who sustained gunshot injury to neck. Color
Doppler sonogram reveals traumatic vertebrojugular arteriovenous fistula
(arrows) that was confirmed on follow-up angiography. JUG V = jugular
vein, VERT = vertebral artery.
|
|
Waveform Changes Throughout the Cardiac Cycle
Highly Resistive Dampened Waveforms
Small, blunt percussive waveforms with little or no diastolic flow (also
called "knocking" or "stump-thump" waveforms) occur
proximal to a complete or nearly complete vascular occlusion
[8]
(Fig. 13). These waveforms are
characterized by a high-resistance pattern with diminished or reversed
diastolic flow. This appearance can also be a sign of dissection ( 76% of
cases) and should prompt a search for an intimal flap
[8]. A similar pattern can be
seen at bends, kinks, and side branches.
View larger version (69K):
[in this window]
[in a new window]
[as a PowerPoint slide]
|
Fig. 13. —Blunt, percussive waveforms in 29-year-old man with complete
occlusion of right common carotid artery because of Takayasu's arteritis.
Spectral Doppler sonography waveforms obtained immediately proximal to
occlusion show only diminutive and dampened percussion and no visible flow
during diastole.
|
|
Swirling or Bidirectional Flow
Apart from the normal boundary layer separation at the carotid bulb, flow
reversal within a carotid artery segment raises concern for the presence of
tandem stenoses or dissection (Fig.
14A,
14B,
14C). The abnormal hemodynamic
pattern created at one lesion can overlap that of a second and produce
abnormal waveforms and eddy currents. A similar pattern can be seen at bends,
kinks, and side branches.
View larger version (117K):
[in this window]
[in a new window]
[as a PowerPoint slide]
|
Fig. 14A. —Bidirectional flow in internal carotid artery of 78-year-old
woman with prior right carotid endarterectomy and recurrent amaurosis fugax.
Spectral Doppler sonography tracings from proximal internal carotid artery
show high-velocity antegrade flow, suggesting high-grade stenosis. Note
presence of intermittent cardiac arrhythmia.
|
|
View larger version (94K):
[in this window]
[in a new window]
[as a PowerPoint slide]
|
Fig. 14B. —Bidirectional flow in internal carotid artery of 78-year-old
woman with prior right carotid endarterectomy and recurrent amaurosis fugax.
Spectral Doppler sonography tracings from mid internal carotid artery show
retrograde flow in posterior portion of vessel. This finding suggests second
tandem stenosis distally, producing swirling current of blood in interposed
arterial segment.
|
|
View larger version (70K):
[in this window]
[in a new window]
[as a PowerPoint slide]
|
Fig. 14C. —Bidirectional flow in internal carotid artery of 78-year-old
woman with prior right carotid endarterectomy and recurrent amaurosis fugax.
Right carotid arteriogram confirms proximal and distal internal carotid artery
stenosis (arrows).
|
|
Cyclical Flow Perturbations
The presence of an intraaortic balloon pump can dramatically alter the
appearance of carotid and vertebral Doppler waveforms because of the
sequential inflation and deflation of the balloon (Fig.
15A,
15B). In these patients, it is
important to recognize the cause of these perturbations because they can lead
to overestimation or underestimation of true flow velocities through an
arterial segment.
View larger version (87K):
[in this window]
[in a new window]
[as a PowerPoint slide]
|
Fig. 15A. —Superimposed cyclic flow perturbations in common carotid
artery because of presence of intraaortic balloon pump. Doppler sonogram shows
55-year-old man with ischemic cardiomyopathy. Waveforms in right common
carotid artery show second peak of forward flow (arrow) during
systole corresponding to inflation of intraaortic balloon. At end of diastole,
and immediately preceding next beat, there is transient reversal
(arrowhead) that corresponds to deflation of balloon.
|
|
View larger version (72K):
[in this window]
[in a new window]
[as a PowerPoint slide]
|
Fig. 15B. —Superimposed cyclic flow perturbations in common carotid
artery because of presence of intraaortic balloon pump. Doppler sonogram shows
36-year-old man with ischemic cardiomyopathy and intraaortic balloon pump.
Less-organized wave pattern is seen in left common carotid artery of this
patient. Presence of balloon pump complicates analysis of underlying carotid
disease, and measurement of flow velocities may necessitate temporary
deactivation of balloon pump.
|
|
Transmitted Percussion Waves
Small, regular percussion waves are seen when the examiner performs a
temporal tap maneuver to identify the external carotid artery and discriminate
it from the internal carotid artery. The reflected pulsations from this tap
will be propagated along the vessel in both directions and can be detected
caudally at the transducer (Fig.
16A,
16B). Although often seen only
in the external carotid artery, less defined and smaller waves can
occasionally be identified in the internal carotid artery.
View larger version (77K):
[in this window]
[in a new window]
[as a PowerPoint slide]
|
Fig. 16A. —68-year-old asymptomatic woman with percussive waves because
of temporal tap maneuver. Spectral Doppler sonography tracing obtained during
temporal tap (T) shows external carotid artery. Serrate distortion of pulse
contour produced by tapping temporal artery is well defined, with deflection
occurring predominantly toward baseline.
|
|
View larger version (76K):
[in this window]
[in a new window]
[as a PowerPoint slide]
|
Fig. 16B. —68-year-old asymptomatic woman with percussive waves because
of temporal tap maneuver. Spectral Doppler sonography tracing obtained during
temporal tap (T) shows internal carotid artery. Changes produced by tapped
percussions are evident in internal carotid artery and external carotid artery
tracings and therefore have been transmitted around carotid bulb. It is
important to examine both carotid vessels under consideration. If these
perturbations are found in only one of two vessels in question, that vessel is
always external carotid artery. When percussive waves are detected in both
vessels, waves are sharper and of higher amplitude in external carotid artery
in 74% of cases.
|
|
Conclusion
The shape and character of carotid and vertebral Doppler waveforms can
disclose a variety of underlying cardiovascular abnormalities. Systemic
circulatory disorders and regional flow disturbance in the vessels of the neck
can be suspected and diagnosed with close inspection for changes in the pulse
contour.
Acknowledgments
We thank Susan Murray and Carrie Poole for assistance with manuscript
preparation.
References
- Kotval PS. Doppler waveform parvus and tardus: a sign of proximal
flow obstruction. J Ultrasound Med1989; 8:435
–440[Abstract]
- Kallman CE, Gosink BB, Gardner DJ. Carotid duplex sonography:
bisferious pulse contour in patients with aortic valvular disease.
AJR 1991;157:403
–407[Abstract/Free Full Text]
- Cohn KE, Sandler H, Hancock EW. Mechanisms of pulsus alternans.
Circulation1967; 36:372
–380[Abstract/Free Full Text]
- Kliewer MA, Hertzberg BS, Kim DH, Bowie JD, Courneya DL, Carroll
BA. Vertebral artery Doppler waveform changes indicating subclavian steal
physiology. AJR2000; 174:815
–819[Abstract/Free Full Text]
- AbuRahma AF, Pollack JA, Robinson PA, Mullins D. The reliability of
color duplex ultrasound in diagnosing total carotid artery occlusion.
Am J Surg1997; 174:185
–187[Medline]
- Macchi C, Catini C. The anatomy and clinical significance of the
collateral circulation between the internal and external carotid arteries
through the ophthalmic artery. Ital J Anat Embryol1993; 98:23
–29[Medline]
- Verbeeck NY, Vazquez Rodriguez C. Patent internal and external
carotid arteries beyond an occluded common carotid artery: report of a case
diagnosed by color Doppler. JBR-BTR1999; 82:219
–221
- Hennerici M, Steinke W, Rautenberg W. High-resistance Doppler flow
pattern in extracranial carotid dissection. Arch
Neurol 1989;46:670
–672[Abstract]
CiteULike 
Complore 
Connotea 
Del.icio.us 
Digg 
Reddit 
Technorati What's this?
Top
Introduction
Typical Carotid and Vertebral...
