Colour Doppler

Question 1

Varicose veins

Answer 1

Failing valves result in reflux, depicted by colour Doppler & eventually vein falls stretch & billow

Question 2

DVT

Answer 2

Clarifies if something is partially or completely occluded
- common to get mural thrombosis in aneurysms

Question 3

Anechoic spaces

Answer 3

Use colour Doppler to check all anechoic spaces found
- eg; renal cyst/hydronephrosis could be a renal aneurysm

Question 4

Ventricular Septal Defect (VSD)

Answer 4

Directional power Doppler is utilised to depict the hole

Question 5

Normal artery layers

Answer 5

1- intimal layer (inner wall) - echogenic inner border

2- media layer - hypoechoic

3- adventitia - echogenic

Question 6

Plaque formations

Answer 6

Usually found in intima-media region

Question 7

Calcific plaque

Answer 7

• takes a long time to form; has hyperechoic edge that often causes shadowing
• AKA irregular (dystrophic) echogenic plaque
• can obscure/shadow Doppler shift & mimic focal segment of occlusion
• use pulse wave spectoral interrogation to show velocities & clarify shadowing Vs occlusion

Question 8

Avoiding shadows

Answer 8

• shift our interrogation angle to circumnavigate the plaque
• may need to roll/move Pt to diff scanning position!!!

Question 9

PW Spectoral dooper

Answer 9

• shows a trace which quantifies the velocity of blood moving during time (measure the PSV or EDV)
• offers real time info* about the vessel (low Vs high resistance)
• allows us to distinguish an artery from a vein
• shows changes in anatomy of the vessel at the same time as seeing the velocity info*
• allows us to hear blood as it pulses
• allows identification of cause of an audible bruit (post auscultating hear sounds)

Question 10

Operator error occlusions

Answer 10

• vertebral vein, which has slow moving flow… involves shadowing from the vertebrae & without adjusting the colour scale/bandwidth it may look like an occlusion

Question 11

Stenosis

Answer 11

• comparing velocities in normal artery Vs where stenosis occurs
• get graded on dividing the peak velocity of the normal Vs the stenosed region: 4 req prompts surg review

Question 12

Trouble shooting

Answer 12

Aliasing with No narrowing of the lumen - It’s YOU & yr machine setting not the Pt

Question 13

Claudication

Answer 13

• caused by stenosis in the leg arteries
• results in leg pain/weakness
• PVD results also
• common in diabetics & smokers

We must measure Pre-stenosis-Post velocities to compare all of them!!!

Question 14

Fake aliasing

Answer 14

• the probe frequency is too high (lower freq* probes are able to demonstrate high velocity flow more appropriately)
• colour PRF scale is set too low
• spectral window is not ‘filled in ‘ & there’s No spectral broadening
• No elevation in upstream (a region prox* to the aliasing demonstrate the same vel* as the next segment)
• No post-stenotic turbulence

Question 15

High resistance wave form

Answer 15

= high peak, potentially biphasic, or even triphasic, but NOT a continuous wave form between pulses

Seen in:
- peripheral limbs
- ECA (extern* carotid art)of the face
- IMA (inferior mesenteric Art) to bowel
- MCA (medial cerebral art*) in foetal brain

Question 16

Low resistance waveform

Answer 16

= monophasic looking, drawn out w No gaps between pulses, spongy like brain behaviour draws up the blood during diastole (doesn’t return to 0 on the spectrum)
- internal carotid art*
- renal arteries
- vertebral artery - feeds cerebellum
- umbilical artery - from placenta to baby (can be used to detect lack of supply)

Abnormal patterns
Tardis Parvus - delayed pattern/pulse across time (no quick upstroke) & lower peak
Lack of movement at all

Pitfall:
Tardis Parvus can be mimicked/simulated by inappropriately set scale & trace is minuscule… it could look like it!!
* reduce yr scale to ensure the waveform reaches across the whole scale to ensure U can see the whole waveform

Question 17

High risk plaque

Answer 17

• two diff echogenicitis - heterogeneous plaque
• hypoechoic plaque = soft & unstable!!
• the dark the plaque, the higher the risk!! Independent of degrees of occlusion

Question 18

Over/Underestimating plaque

Answer 18

Be aware of how the angle may change the quantification of an occlusive plaque

Question 19

Highly fragile plaque

Answer 19

• demonstrate any hypoechoic plaque from multiple planes & complete the sheet to depict the shape & composition of the plqur

Question 20

Ulcerative plaque

Answer 20

Need to depict:
- cavity within the plaque
- cavity is sharply marginated
- there is flow within the cavity

Question 21

Embolus

Answer 21

• Plaque gets weakened across time
• plaque fissure gets filled w blood/clot/plaque
• rupture of plaque can cause embolisation of plaque

Question 22

Why would be use Power Doppler

Answer 22

• it is more sensitive than colour Doppler - tho sometimes U need to turn down the gain
• ## doesn’t rely upon angular inception - though can be clear with some angle

Question 23

Wall Thump waveform

Answer 23

• flow hitting against a ‘wall’, no through flow!!
• shows some forward flow & nearly instantaneous/simultaneous backward jolt in flow

Question 24

Subclavian Steal Syndrome

Answer 24

Reversal of blood flow in vertebral artery due to reduced flow into subclavian artery, eg; to feed an arm

Question 25

Dissections

Answer 25

True lumen Vs false lumen

Mirror artefact can micmic same tho
- intimas are not usually so bright & may create a mirror artifact

Question 26

Fibromuscular displasia

Answer 26

• aliasing in arteries due to Dx
• normal malformations in these Pts
• long segments & younger Pts