Chapter 30 - Duplex scanning and color flow imaging Flashcards
Recommended adjustments for color flow imaging
1) decrease color scale to detect slower venous velocities
2) decrease wall filters
3) increase color gain
4) alter steering of color box
5) heel-toe movement of transducer to optimize angle of insonation
Coaptation
“to fit together”
compressibility of veins on ultrasound
Perforator vein diameter cutoff for likely normal
Normal < 3 mm
Upper extremity venous changes in presence of dialysis graft
1) increased flow velocity
2) increased volume flow
3) pulsatile flow
4) no response to distal compression
5) incompressible vessel
6) collateral channels evident
Rouleau
“roll” formation = RBC arranged like rolls of coils
Sluggish flow = proximal obstruction, proximal venous hypertension, increase immunoglobulin
Chronic changes after acute DVT
1) echogenic
2) collateralization
3) recanalization
4) synechiae = intraluminal striation
5) thickened wall
6) non-dilated vessel
Synechiae
Thrombus slowly converted to fibrous bands appearing as intraluminal striations
Normal valve closure time after distal compression release
< 0.5 s
Lymph node on ultrasound
1) brighter echoes in centre
2) low level echoes surrounding
Abscess on ultrasound
various from well-defined to ill-defined; heterogenous
Cyst on ultrasound
well-defined fluid anechoic with posterior enhancement
Baker’s cyst has neck to joint space
Effusion on ultrasound
anechoic
Hematoma on ultrasound
Various from well to ill-defined
Heterogenous
Low level echoes but can become anechoic over months
Little through-transmission or posterior enhancement
Amasotrophy
Tendons brightens and darkens with angulation of US
Size of perforator that is associated with 90% reflux
> 3.5 mm
