Vasc Carotid duplex scanning & color low imaging Ch18 and ch 22 atypical vasc disorders

is internal carotid artery high or low resistance

low

what transducer is used for carotid scanning

5-15 MHz depending on size of pt

what do B mode images evaluate

presence, location, severity of plaque and surface characteristics of vessel

what are minimal longitudinal images of normal carotid procedure

CCA, Bifurcation, ICA (including bulb)

what are minimal transverse images of normal carotid procedure

prox ICA

what are ACR guidleines for long color flow images

distal CCA; mid, prox of ICA; long ECA; vert

describe sono of fatty streak plaque

homogenous low level echos

describe sono of fibrous plaque

soft, low-medium echos

describe sono of complex plaque

low, medium and high level echos, hetero

what is water hammer effect

when vessel demonstrates piston-like motion on B mode due to an occlusion

what are flow separation zones

high momentum blood separates from the laminae of surround fluid (blood from tight stenosis runs into normal flow)

should you use large or small color box to optimize color

small

increasing color scale does what to Nyquist limit/PRF

increases

what should you do to color scale for low velocity flow

lower scale/decrease PRF

color gain too high will make flow appear _________

turbulent

color gain to low will make flow appear ________

low or no

PW has range resolution

what makes up returning signal of spectral doppler

individual frequencies

sample volume should be increased or decreased when searching for a small jet or occlusion

increased

what type of resistance does CCA have

low

describe ICA waveform

less pulsatile than ECA, rapid up and down stroke w/high diastolic component, notch not seen

describe ECA waveform

high up and down stroke w/low diastolic component, dicrotic notch seen

what is temporal tap

tapping on the temporal artery can confirm ECA vs ICA

what doppler measurements should be included in exam

Peak and end of: CCA - Prox and distal; bulb, ICA - prox, mid, distal; peak systolic of proximal ECA

what is normal flow for ICA

PSV <120 cm/sec; EDV <40 cs/sec; ICA/CCA ratio <2.0

What is display on the XYZ axis of spectral Doppler waveform analysis

X-time; y-frequencies/velocity; z-amplitude

At a stenosis the waveform will be what

Higher velocities(Accelerated flow) systole and diastole

What type of flow will be seen distal to a stenosis?

Dampened with more rounded up stroke, low resistance, and turbulence

If peak systolic velocity of ICA is greater than 230 cm/s and end diastolic velocity is >100 cm/s, what is the percent of stenosis?

>70%

If PSV of ICA is 125-230 cm/s and EDV is 40-100 cm/s. What is the percent of stenosis?

50-69%

If PSV of ICA is <125 cm/sec what is degree of stenosis?

0 to 50%

How can you calculate percent of stenosis?

(True lumen minus remaining lumen) divided by True lumen (x100)

A ICA/CCA systolic velocity ratio of 2 to 4 indicates — % stenosis

50-69%

>4 ica/cca (systolic) ratio indicates — % diameter stenosis

70%

What is a subclavian steal

Differences of 15-20 mmHg in 2 subclavian artery pressures (steal in arm w/lower pressure)

Why are the vertibral arteries Important when imaging carotids

Because they connect to basilar and help create the circle of Willis

If Doppler from ICA has higher than expected resistance, what does this indicate?

Distal obstruction

What does low velocities, increased acceleration time, and rounded waveforms of CCA indicate

Proximal disease

What is normal flow direction of vertebral artery?

antegrade (Toward head)

What is waveform of vertebral artery?

Low resistance (scaled down version of ICA)

Is left or right vertebral artery larger

Left

If ICA is completely Occluded What will act as collateral?

Contralateral ICA and CCA

What Waveform will ICA and CCA take on if they are compensating for occluded CCA

Increased systolic and diastolic velocities

What are three conditions that should exist in order to use carotid criteria

Plaque, velocity acceleration in area of plaque, post stenotic turbulence distal to plaque

What is it called when vertebral arteries direction of flow is retrograde

It is abnormal, subclavian steal

If there is a CCA occlusion, what will Happened to the ICA and what will the spec Doppler look like?

It will remain open due to collateral flow from ECA and it will have abnormal Doppler

What is a (carotid) endarterectomy (CEA)

Surgical intervention to remove plaque from an artery, intima and media are removed

— % of subclavian steal is on the — side

90, left

What is known as the pulseless disease?

Takayasu’s arteritis

What is takayasu’s arteritis

Inflammatory vasculitis that leads to thickening of the arterial wall, causing narrowing

Who is commonly affected by Takayasu’s arteritis

Women of child bearing age

Temporal arteritis also called

Giant cell Arteritis or hortons arteritis

What are symptoms of temporal arteritis

Headache, temporal tenderness, vision changes anechoic halo on Sono due to edema in vessel walls