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US review
March 9, 2011
Rule out DVT
If the vein completely compresses
there is no underlying clot.
clot
no clot
Linear Array Probe (5-10 mHz)
Patient reclines at 45o
Hip externally rotated
Note: SFV – “superficial” femoral vein is a deep vein!
Just 2 key areas to compress
Our protocol: 4 compression clips
CF-saph
bifurcation
pop
“trifurcation”
A normal exam:
Clip #1
CF-saph
CFV – G. Saphenous Junction
Clip #2
bifurcation
Bifurcation: SFV and DFV
Clip #3
pop
Pop V
Clip #4
“trifurcation”
“trifurcation”: pop divides
Some clots:
DVT in CFV
Clip: partially occlusive DVT
movie: mobile DVT
movie: DVT in CFV
Movie: DVT in pop
Chronic DVTs look different
Chronic DVT
– shrunken
– fibrotic (hyperechoic)
– collaterals
– recanalized
clip: lymph node
The exam is simple!
Stuff you don’t have to know:
the mid-thigh
the calf
Doppler
You can skip:
mid-thigh: SFV
Calf veins: OK to skip
Calf DVTs
- Unreliable to diagnose: < 70% sensitivity
- Unclear significance: 75% resolve without treatment
But what if you find a calf DVT?
Plan A: anticoagulate
Plan B: ASA only. Monitor for extension
(Not all calf veins are equally important)
Clip: calf veins
Is Doppler needed?
No. Compression is sufficient.
Color can sometimes help identify vessels.
Doppler can give false normals:eg non-occlusive DVT has normal augmentation.
Doppler flow info:
Augmentation:
- squeeze the calf and blood rushes past the probe
- implies no obstruction between calf and probe
Respiratory phasicity:
- implies no obstruction up in pelvis
- flow stops on inhale, goes on exhale
Venous flow(note respirations)
phasic flow and augmentation
What is “duplex”?
2 modalities together: U/S + Doppler
Quiz!
A
B
C
A
C
DB
A
B
Where on the leg are we?
The End