carotid duplex imaging

Question 1

capabilities

Answer 1

localize lesion in extracranial carotids
progression of disease
id surface characteristics
evaluate pulsatile mass

Question 2

what can cause over estimation of disease

Answer 2

cardiac increased output (bilateral symptoms)
tortuous vessel
compensatory flow
inappropriate doppler angle

Question 3

what can cause underestimation of disease

Answer 3

altered cardiac output:
( cardomyopathy ,,, LVAD left ventricular assist device)

jet of accelerated flow missed
long smooth plaque formation
stenosis at area of dilation
inappropriate doppler angle

Question 4

scan rates are slowest with which type of DOPPLER
CDI
spectrial
continuous wave

Answer 4

CDI

because of multiple transmit and recieve pulses

Question 5

Spectral Doppler what is the X & Y axis units

Answer 5

x- time

y -frequency shifts

Question 6

which doppler teq has a fixed sample size

Answer 6

CW

Question 7

Plaque Characteristics

hypoechoic and homogeneous

Answer 7

low level echoes of similar appearance

fatty streaks

Question 8

Plaque Characteristics
homogeneous
low to med level echoes of similar appearance

Answer 8

fibrous plaque

Question 9

Plaque Characteristics

echoic and heterogeneous

Answer 9

all level echoes complex plaque

Question 10

Plaque Characteristics

hyperechoic

Answer 10

very dense highly reflective calcific plaque that may cause shaddowing

Question 11

Plaque Characteristics

sme echogenicity of blood in b-mode

Answer 11

thrombosis

Question 12

stenosis should be visible from how many projections

Answer 12

2

Question 13

what might be indicated by high resistant flow in ICA

Answer 13

carotid siphon sidease

Question 14

what is indicated by diminished CCA velocities bilaterally ?

unilaterally?

Answer 14

poor cardiac output (bilateral

prozimal disease -eg innominate or common carotid artery

Question 15

what is essential to compare and record when abnormal flow characteristics are recorded in one segment

Answer 15

same segment of contralateral side

proximal and distal segments of ipsilateral side

Question 16

NASCET criteria

normal % stenosis PSV and EDV

Answer 16

<125 cm/sec

Question 17

NASCET criteria

<50 % stenosis PSV and EDV

Answer 17

<125 cm/sec

Question 18

NASCET criteria

50-79 % stenosis PSV and EDV

Answer 18

> 125 cm/sec PSV

<140 cm/sec

Question 19

NASCET criteria

80-99% stenosis PSV and EDV

Answer 19

> 125 cm/sec PSV

>140 cm/sec

Question 20

NASECT criteria for occlusion

Answer 20

Absent velocities

Question 21

what is 70% stenosis ICA / CCA ratio

northamrerican symptomatic carotid endarterectomy trial

Answer 21

> or equal to 4.0

Question 22

Critical criteria in determining an occlulsion

3

Answer 22

CCA low or absent diastolic component

evidence of commercialization Eg ECA may exhibit high flow in end diastolic

Absent ICA doppler signal or pre-occlusive thump

Question 23

if Aliasing occurs I should _____ the PRF

Answer 23

raise the PRF

Question 24

maximum frequency is ____PRF

flow info greater than ____PRF

Answer 24

max frequency is 1/2 PRF

flow info greater than 1/2 PRF cannot be displayed bc of Nyquist limit

Question 25

methods for increasing PRF

5

Answer 25

decrease the baseline , increase doppler scale

chang tx frequency

alter angle of insonation

decrease depth

use CW

Question 26

what machine setting can be changed to reduce mirror artifact

Answer 26

lower the gain

Question 27

when does helical flow occur

what does the signal look iike

Answer 27

when flow moves into wider portion of a vessel (bulb)

you will see spectrial signals above and below the baseline

doppler angle is constantly changing

flow is not laminar spectrial broadening is present

Question 28

intraperative monitoring in cerebrovascular procedures

Answer 28

used during endarterectomy

id defects secondary to surgery and see platelet aggregation

evaluates hemodynamic significance of wall irregularity

use >12 MHz hocky stick

wound is filed with sterile saline

areas of flow disturbance are id’ed

gray scale used to detect subtle wall defeccts