CH 4: doppler waveform analysis in the upper and lower extremities

advanced non-invasive vascular technology

Doppler waveform analysis helps to confirm the ________, ________, and approximate _________ of arterial occlusive disease.

• Diagnosis

• Severity

• Location

Doppler waveform analysis provides follow-up information about progression of (1)________, results of medical (2)_________, or post-(3)__________ status.

1. Disease

2. Therapy

3. Operative

Advanced non-invasive vascular technology is combined with _________ ________ to produce doppler waveforms.

Segmental pressures

What are some limitations with advanced non-invasive vascular technology? (3)

• Casts/Extensive Bandages

• Temperature Changes

• Uncompensated Congestive Heart Failure

Dampened waveforms on doppler waveform analysis may be due to…

Uncompensated congestive heart failure

Continuous wave dopplers is unable to discriminate (1)_________ from (2)__________.

1. Stenosis

2. Occlusion

1. Arteries affected by hot temperatures or exercise will cause vaso(dilation/constriction).

2. What waveform will be seen?

1. Vasodilation

2. High resistive → Low resistive

1. Arteries affected by cold temperatures will cause vaso(dilation/constriction).

2. What waveform will be seen?

1. Vasoconstriction

2. Increased pulsatility

The artery on the left is affected by vaso(dilation/constriction).

Vasoconstriction

The artery on the left is affected by vaso(dilation/constriction).

Vasodilation

Define the Doppler effect.

When a wave is reflected from a moving target

What is the term for this:

When a wave is reflected from a moving target

Doppler Effect

What is the primary moving target with the doppler effect?

Red blood cells (RBC)

Define the Doppler shift.

Difference between frequency of the wave received and frequency of the transmitted wave

What is the term for this:

Difference between frequency of the wave received and frequency of the transmitted wave

Doppler Shift

There is a _________ _______ whenever there is relative motion between the source and the receiver of the sound.

Doppler effect

With continuous wave doppler, _________ is the moving target.

Blood

With continuous wave doppler, _________ is the stationary source.

Transducer

With continuous wave doppler blood is the…

Moving target

With continuous wave doppler, the transducer is the…

Stationary source

1. How many piezoelectric crystals are there with continuous wave doppler?

2. Describe the crystals roles?

1. 2

2. • One constantly sending ultrasound

   • One constantly receiving reflected waves

Label the waveforms emitted in this image.

1. US Wave

2. Doppler Shift Wave Frequency

List the 2 types of Doppler Velocimetry.

• Analog

• Digital

What is another term for digital doppler velocimetry.

Spectral analysis

Of the 2 types of doppler velocimetry, which is considered ‘old’ and ‘outdated’?

Analog

Of the 2 types of doppler velocimetry, which is considered better?

Digital (spectral analysis)

Which doppler velocimetry form employs a zero-crossing frequency meter to display the signals graphically on a strip-chart recorder?

Analog

Analog doppler velocimetry employs a (1)_____-_________ frequency meter to display the signals graphically on a (2)______-______ recorder.

1. Zero-Crossing

2. Strip-Chart

With analog doppler velocimetry, the (1)_______ counts every time the (2)_____ signal crosses the (3)_____ (baseline) within a specific time span.

1. Circuitry

2. Input

3. Zero

Which form of doppler velocimetry has circuitry that counts every time the input signal crosses the zero (baseline) within a specific time span?

Analog

With analog doppler velocimetry, the number of times the sound waves (1)_______ each second varies and because the (2)_________ of blood flow varies during the cardiac cycle, the equipment estimates the (3)_________ of the reflected signal.

1. Oscillate

2. Direction

3. Frequency

Which form of doppler velocimetry is this?

The number of times the sound waves oscillate each second varies and because the direction of blood flow varies during the cardiac cycle, the equipment estimates the frequency of the reflected signal.

Analog

Why is it hard to distinguish an abnormal waveform with analog doppler?

Due to lack of sensitivity

An analog waveform of the CFA with the absence of flow reversal is hard to distinguish if abnormal due to a lack of _________ with analog doppler.

Sensitivity

1. It is hard to distinguish abnormal waveforms due to a lack of __________ with analog doppler.

2. Because of this, it does not allow for the depiction of flow ________.

1. Sensitivity

2. Reversal

1. If this waveform was obtained from an analog doppler velocimetry, would this easily be ruled out as abnormal?

2. If no, why not?

1. No

2. Analog has a lack of sensitivity and does not allow for the depiction of flow reversal

With doppler velocimetry, between the two, which has acceptable accuracy and is not as sensitive?

Analog

With doppler velocimetry, between the two, which has more sensitivity?

Digital (spectral analysis)

List the 4 drawbacks of analog.

• Noise

• Less sensitivity

• Underestimate high velocities

• Overestimate low velocities

Digital (Spectral analysis) displays (1)_________ on the vertical axis and (2)______ on the horizontal axis.

1. Frequency

2. Time

The amplitude of backscattered signals with digital (spectral analysis) can be seen at any given _________ and _____.

• Frequency

• Time

Digital (Spectral analysis) can display what 3 factors?

• Frequency

• Time

• Amplitude of backscattered signals

Digital (spectral analysis) differs from analog recording in the way that it is more sensitive and is free of…

Drawbacks

Which of the two doppler velocimetry options has more frequency content?

Digital (spectral analysis)

Which of the two doppler velocimetry options allows displays of flow reversal? (i.e., triphasic waveform)

Digital (spectral analysis)

Which form of doppler velocimetry is seen here?

Digital (spectral analysis)

What kind of probe does a continuous wave doppler exam use?

(Be specific on frequency)

8 - 10 MHz doppler probe

Continuous wave doppler waveforms are combined with what else?

Segmental pressures

What upper extremity arteries are examined with continuous wave doppler exams? (5)

• Subclavian

• Axillary

• Brachial

• Radial

• Ulnar

What lower extremity arteries are examined with continuous wave doppler exams? (6)

• CFA

• SFA

• Popliteal

• PTA

• DPA

• Peroneal

Where is the PTA found?

Medial malleolus

What artery is found at the medial malleolus?

PTA

Where is the DPA found?

Top of foot

What artery is found at the top of the foot?

DPA

Where is the peroneal artery found?

Lateral malleolus

What artery is found at the lateral malleolus?

Peroneal artery

What kind of exam is being performed here?

Continuous wave doppler

List the 6 potential sources of technical errors for a continuous wave doppler exam.

• Improper probe position

• Inadvertent probe motion

• Incorrect angle

• Inadequate amount of gel

• Excessive pressure on probe tip

• Insufficient period of rest by the patient before testing

An insufficient period of rest prior to a CW doppler exam can cause technical errors.

1. Give an example of what would disrupt that period of rest.

2. How would that action affect the waveforms?

1. Exercise

2. High resistive waveform → Low resisitve waveform

T or F:

With CW doppler exams, you can make a normal vessel look abnormal.

True

T or F:

With CW doppler exams, you can make an abnormal vessel look normal.

False

What exam is being performed here?

CW Doppler Exam

What waveform is deemed ‘normal’ when taken on an artery?

Triphasic

What waveforms are deemed ‘abnormal’ when taken on an artery? (3)

• Monophasic

• Non-Pulsatile

• Absent

List the 5 signals/parts of a triphasic waveform.

• Rapid Upstroke

• Sharp Peak

• Rapid Downstroke

• Short Peak Below the Baseline

• Resumption of Forward Flow

List the 4 signals/parts of a monophasic waveform.

• Slow Upstroke

• Rounded Peak

• Slow Downstroke

• No Reversal

What part of a triphasic waveform represents flow reversal?

Short Peak Below the Baseline

A short peak below the baseline with a triphasic waveform represents…

Flow reversal

1. Which leg is normal?

2. Which leg is abnormal?

1. Left

2. Right

1. What kind of waveforms are seen here?

2. If this was taken on a CW doppler exam, is the waveform normal or abnormal?

1. Biphasic (Due to short peak below baseline)/Monophasic

2. Abnormal

1. What kind of waveforms are seen here?

2. If this was taken on a CW doppler exam, is the waveform normal or abnormal?

1. Triphasic

2. Normal

What doppler waveform can be considered normal or abnormal (with controversy behind it)?

Biphasic

What is the most essential thing to observe for when obtaining waveforms on a CW doppler exam?

Deterioration of the doppler signal from one level to the next

List 2 examples of waveform changes that indicate deterioration of signal quality from one level to the next.

• Triphasic to biphasic

• Triphasic to monophasic

Where is disease located if there is a deterioration of doppler signal quality from one level to the next?

Between the 2 levels

1. A CW doppler exam cannot differentiate between which 2 pathologies?

2. Explain why.

1. Stenosis & Occlusion

2. Cannot detect velocities < 6 cm/sec

CW doppler cannot detect velocities (1)_____ than (2)____ cm/sec.

1. Less

2. 6

If there is an inability to elicit doppler signals, rather than occlusion, what can it suggest instead?

Slow velocities moving through the vessel (Trickle flow)

What is trickle flow?

Slow velocities moving through the vessel

Inflow or outflow disease?

Blood flowing into the lower extremities

Inflow disease

Inflow or outflow disease?

Blood moving out into the extremities

Outflow disease

Inflow disease represents blood flow…

Flowing into the lower extremities

Outflow disease represents blood flow…

Moving out into the extremities

List 2 examples of inflow disease.

• Aortoiliac disease

• Iliac disease

List 2 examples of outflow disease.

• Femoral-popliteal disease

• Tibial disease

If there is deterioration from one level to the next, where is disease most likely?

Between the 2 areas

1. Which leg is normal?

2. Which leg is abnormal?

1. Both

2. Neither

What kind of waveforms are seen in this image?

Triphasic

Label the parts of this triphasic waveform.

1. Rapid Upstroke

2. Sharp Peak

3. Rapid Downstroke

4. Short Peak

5. Resumption of Forward Flow

What do the common femoral artery waveforms most likely represent?

• Describe L & R waveforms

  • If diseased, where disease is located and if it is inflow/outflow disease

• Left: Normal triphasic waveform

• Right: Abnormal monophasic waveform

  • Proximal disease (iliac artery)

    • Inflow disease

What do the popliteal artery waveforms most likely represent?

• Describe L & R waveforms

  • If diseased, where disease is located and if it is inflow/outflow disease

• Left: Abnormal biphasic waveform

  • Proximal disease (femoral artery)

    • Outflow disease

• Right: Abnormal monophasic waveform

  • Proximal disease (femoral artery)

    • Outflow disease

What do the posterior tibial artery waveforms most likely represent?

• Describe L & R waveforms

  • If diseased, where disease is located and if it is inflow/outflow disease

• Left: Abnormal monophasic waveform

  • Proximal disease (popliteal artery)

    • Outflow disease

• Right: Abnormal monophasic waveform

  • Proximal disease (popliteal artery)

    • Outflow disease

What do the dorsalis pedis artery waveforms most likely represent?

• Describe L & R waveforms

  • If diseased, where disease is located and if it is inflow/outflow disease

• Left: Abnormal monophasic waveform

  • Proximal disease (posterior tibial artery)

    • Outflow disease

• Right: Abnormal monophasic waveform

  • Proximal disease (posterior tibial artery)

    • Outflow disease

1. Where is the most significant arterial disease of the left extremity?

2. Explain why.

3. What is the name of the diseased area based on location?

1. Between the popliteal artery and the PTA

2. Where there is the most dramatic waveform change

3. Pop-Infrapop arterial disease

A patient with 3-block claudication has an exam done and you are getting triphasic waveforms. Although that is considered normal, the exam is not done because the study needs to be repeated.

What should the patient do prior to repeating the exam?

The patient should exercise first

How should normal post-exercise waveforms seen with CW doppler appear? (3)

• Maintain pre-exercise waveform

• Augment pre-exercise waveform

• All waveform components above the baseline

How does an abnormal post-exercise waveforms seen with CW doppler appear? (4)

• Slow upstroke

• Rounded peak

• Slow downstroke

• No reversal

What does exercise produce to the muscles?

Demand for blood flow

Exercise produces an element of arterial…

Vasodilation

Exercise produces arterial vasodilation, therefore post-exercise waveforms will appear how?

Low-resistive