Ultrasound evaluation for deep venous thrombosis (DVT) is one of the 11 core ultrasound applications for emergency physicians as listed in the 2008 American College of Emergency Physicians guidelines (1). Because ultrasound applications started to be implemented into medical school curriculum in many countries, learning basic ultrasound applications as early as possible will benefit medical students and junior residents. In this post, I will share lower extremity venous ultrasound illustrations with you.
Indications
The clinical indications for performing a lower venous ultrasound examination is the suspicion of a lower extremity DVT in a swollen or discoloured leg.
Transducer
Select a high-frequency linear transducer, (5-10) MHz transducer since it provides optimal venous copmression and image resolution.
Remember Risk Factors of DVT
- Age > 60
- Cancer
- Central venous catheter/insertion
- Genetic causes of hypercoagulopaty
- History of DVT
- Immobilization
- Obesity
- Pregnancy
- Smoking
- Trauma or recent surgery
- Use of birth control pills or hormone replacement therapy
Wells Score for Deep Vein Thrombosis
| Criteria | Score |
|---|---|
| Active cancer(treatment ongoing or within previous 6 months or palliative treatment) | 1 |
| Paralysis, paresis, or recent plaster immobilization or of the lower extremities | 1 |
| Recently bedridden for 3 days or more or major surgery within the previous 12 weeks requiring general or regional anesthesia | 1 |
| Localized tenderness along the distribution of the deep venous system | 1 |
| Entire leg swollen | 1 |
| Calf swelling > 3cm compared to asymptomatic leg (measuring 10 cm below tibial tuberosity) | 1 |
| Pitting edema confined to the symptomatic leg | 1 |
| Non varicose collateral superficial veins | 1 |
| Previously documented DVT | 1 |
| Alternative diagnosis at least as likely as DVT | 1 |
Normal DVT Ultrasound Findings
Reference and Further Reading
- American College of Emergency Physicians. Emergency ultrasound guidelines 2008. http://www.acep.org/WorkArea/DownloadAsset.aspx?ID=32878. February 2012.
Note: Visual drawings are inspired by the Point-of-Care ULTRASOUND Book.
