This document provides an overview of deep venous ultrasound for detecting deep vein thrombosis (DVT). It describes the indications, limitations, and standard ultrasound protocol for a focused exam. Key points include: DVT has a high incidence in the US and can lead to pulmonary embolism; ultrasound is a good diagnostic tool as it is non-invasive, portable, and low cost; the standard protocol focuses on assessing compressibility of the common femoral and popliteal veins; findings suggestive of DVT include non-compressibility, echogenic material within the vein, and decreased blood flow despite augmentation.

1. Deep Venous UltrasoundUniversity of Florida-JacksonvilleDepartment of Emergency MedicinePetra Duran-Gehring, M.D.

2. ObjectivesDescribe the indications and limitations of focused ultrasound for the detection of deep venous thrombosisUnderstand the standard ultrasound protocol when performing a focused examDefine the relevant local anatomyDevelop an understanding of doppler physics and instrumentationRecognize the relevant focused findings and pitfalls when evaluation for deep vein thrombosis

3. Deep Venous Thromboembolism Incidence in U.S.: 1 in 1000 people/year10% of proximal DVTs will lead to PE50% of untreated proximal DVTs will lead to PE within 3 months>80% of PEs due to DVTs

4. DVT Risk FactorsRecent TraumaRecent SurgeryImmobilityCancerEstrogen PregnancyOCPsPrior DVT/PEFamily history of hypercoagulabityProtein C or S deficiencyFactor V lieden or Antithrombin III deficiencyAntiphospholipin or anticardiolipin antibodyHomocysteineLupus anticoagulant

5. Physical ExamUnilateral leg swellingTenderness to palpationRednessWarmthPalpable cords- rareHomann’s sign- rarePratt’s signPoor sensitivity and Specificity

6. Lower Extremity DVTPopliteal10%Popliteal + Superficial Femoral42%Popliteal + Superficial Femoral + Common Femoral5%All proximal vessels35%

7. DVT DiagnosticsContrast VenographyFormer gold standardTime consumingIV dye exposurePlethysmographyCTMRIUltrasoundLow costPortableNon-invasive

8. Ultrasound ProtocolsDuplexComprehensiveColor flowDopplerTime consuming (about 45 mins)Limited CompressionFocused techniqueBedside examLook for clot only inCommon femoral veinPopliteal vein

9. Limited Compression UltrasoundFocus on proximal veinsThrombi distal to popliteal rarely embolizeDistal thrombi may propagate to poplitealTherefore, if DVT suspected, must rescan in 3-5 daysClot is identified by the lack of normal compressibility of the veinProven to be as accurate as Duplex US and better than plethysmography in finding proximal clots

10. Lower Extremity Venous AnatomyCommon FemoralCommon FemoralSuperficial (saphenous)DeepDeep Femoral (Profunda)Superficial FemoralPoplitealAnterior TibialPeronealPosterior TibialDeep Femoral Superficial FemoralPopliteal

11. Common Femoral AnatomyCommon Femoral VeinFemoral Artery

12. Femoral Junction AnatomyCommon Femoral VeinSaphenous VeinFemoral Artery

13. Femoral Bifurcation AnatomyCommon Femoral VeinFemoral ArteryProfundaFemoris

14. Superficial Femoral AnatomySuperficial Femoral VeinFemoral Artery

15. Popliteal AnatomyPopliteal VeinPopliteal Artery

16. Scanning TechniqueLinear array probe 6-10 mHzMedium footprintIf pt is obese, may need to use a lower frequency sector probePositioningReverse trendelenbergSemi-sitting with hips in 30 degrees flexion

17. Ultrasonic DVT FindingsNon-compressibilityEchogenic material with lumenDecreased blood flowDespite augmentation

18. CompressionCompress vein using transducerComplete apposition of the vein walls needed to rule out DVTIf compression is not achieved with pressure sufficient to deform adjacent artery, thrombus present

19. Common FemoralPt placed in supine positionLeg externally rotatedProbe indicator to pt’s right

20. Femoral VeinPlace probe in inguinal creaseUse color flow doppler to distinguish vesselsScan from CFV through the SFVCompress as you go

21. Femoral Vein DVT

22. PoplitealPositionProneDecubitusSeated on edge of gurneyKnee bent to increase venous fillingReverse trendelenburgProbe indicator to pt’s right

23. PoplitealPlace probe 10-12 cm above bend in kneeUse color flow doppler to distinguish vesselsScan through to the trifurcation of the poplitealCompress as you go

24. Popliteal Vein DVT

25. Scan ProtocolBegin by palpating femoral pulsePlace transducer over inguinal ligament with probe indicator to pt’s rightScan through the common femoral to the bifurcation (about 10 cm)Move to posterior knee bendScan through popliteal to the trifurcationTake clips to illustrate compressibilityMay need to image the contralateral side if results questionable

26. PearlsAugmentation of flow by compressing the calf can help distinguish the vein from arteryOptimize gain to best see the vascular systemIf case equivocal, scan other side and compareMay scan through the superficial femoral vein is clinical suspicion is high

27. Questions???