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