US review March 9, 2011. Rule out DVT If the vein completely compresses there is no underlying clot.

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