Ultrasonography of deep vein thrombosis

Ultrasonography technique for diagnosing deep vein thrombosis

Ultrasonography of deep vein thrombosis is a non-invasive diagnostic technique used to detect the presence of deep vein thrombosis (DVT) in the venous system. DVT is a condition where a blood clot forms in a deep vein, usually in the legs, which can lead to serious complications such as pulmonary embolism.

Technique

Ultrasonography for DVT typically involves the use of Doppler ultrasound to assess blood flow and B-mode ultrasound to visualize the veins. The procedure is performed by a trained sonographer or a radiologist.

Compression Ultrasound

Ultrasound image showing DVT

Compression ultrasound is the primary technique used to diagnose DVT. The sonographer applies gentle pressure with the ultrasound probe to compress the vein. In a healthy vein, the walls will collapse under pressure, indicating no clot is present. If the vein does not compress, it suggests the presence of a thrombus.

Doppler Ultrasound

Doppler ultrasound is used to evaluate blood flow within the veins. It can detect changes in blood flow patterns that may indicate the presence of a clot. The Doppler effect is used to measure the velocity of blood flow, and abnormalities can suggest a blockage.

Anatomy and Areas of Examination

The most common sites for DVT are the femoral vein, popliteal vein, and the deep veins of the calf.

Femoral Vein

Ultrasound of femoral vein thrombosis

The femoral vein is a major vein in the leg and a common site for DVT. Ultrasound examination of the femoral vein involves scanning from the groin to the knee.

Popliteal Vein

The popliteal vein is located behind the knee. It is another common site for DVT. The ultrasound probe is placed in the popliteal fossa to assess this vein.

Calf Veins

Ultrasound of fibular vein thrombosis

The deep veins of the calf, including the fibular veins, are also examined. These veins are smaller and can be more challenging to assess, but they are important in the diagnosis of DVT.

Clinical Significance

Ultrasonography is the preferred initial test for suspected DVT due to its non-invasive nature, lack of radiation, and high sensitivity and specificity. Early detection of DVT is crucial to prevent complications such as pulmonary embolism, post-thrombotic syndrome, and chronic venous insufficiency.

Limitations

While ultrasonography is highly effective, it has limitations. It may not detect clots in the pelvic veins or in the inferior vena cava. Additionally, the accuracy can be affected by patient factors such as obesity or edema.

Related pages

• Deep vein thrombosis
• Pulmonary embolism
• Doppler ultrasound
• Venous system