IS Case 213: Deep vein thrombosis (DVT)
Imaging Sciences URMC 2008
Publication Date: 2009-05-22
Patient is a 51-year-old-male with left lower extremity pain and swelling.
Ultrasound exam showed a large, nearly occlusive acute deep vein thrombosis (DVT) present within the superior left femoral vein at the level of the profunda femoris, extending inferiorly to the level of the superior popliteal vein. There is associated left lower extremity subcutaneous edema.
Deep vein thrombosis (DVT)
Clinically, deep venous thrombosis (DVT) of the lower extremity can lead to a swollen, tender, and warm limb. DVT imaging is important because untreated DVT can lead to pulmonary embolism with resultant shortness of breath, chest pain, hypoxia, and possible death. Risk factors for DVT include obesity, malignancy, smoking, hypertension, oral contraceptive use, pregnancy, recent surgery, immobilization, and any other prothrombotic state.
Ultrasound is the imaging modality of choice when evaluating for DVT. In acute DVT (14 days or less), a hypoechoic thrombus may be seen within the vessel. Recently thrombosed veins will also demonstrate distention will not be compressible with the ultrasound probe. In some cases a free-floating thrombus can be seen which is not totally adherent to the vessel wall. In subacute thrombus (2 weeks to 6 months), the intravascular thrombus gradually becomes more echogenic. In addition, the vein will become less distended. Flow can be restored through recannalized channels, collateral vessels can be seen. In the chronic phase (greater than 6 months), fibroblasts can invade the thrombus causing scarring and fibrotic tissue formation. Scarred and fibrotic vessel walls can become thickened. Echogenic, intraluminal plaque-like areas can be seen and valve damage may occur.
Pulsed Doppler is used to evaluate vascular waveforms. Normal veins should demonstrate phasic flow which varies with respiration. If phasisity is lost, it may indicate thrombus closer to the heart. A valsalva maneuver may be utilized which will cause abrupt cessation of flow in patent vessels. Vessel augmentation with distal compression can also be used. In normal vessels, flow should be amplified. Color Doppler can used to demonstrate thrombus which may have been missed on grayscale imaging. Baker cysts can cause slow flow within adjacent vessels; thickened valves can be mistaken for thrombus in chronic venous obstruction.
- Zwiebel W, Pellerito J. Introduction to Vascular Sonography. 5th edition. Philadelphia, PA: Elsevier Saunders, 205;403-78.
- White RH. The epidemiology of venous thromboembolism. Circulation. 2003 Jun 17;107(23 Suppl 1):I4-8. [PMID: 12814979]
- Dähnert W: Deep vein thrombosis. In: Radiology Review Manual. 3rd edition. Baltimore,MD: William & Wilkins, 1996; 462-3.