From the Guidelines
For suspected Deep Vein Thrombosis (DVT), a comprehensive duplex ultrasound protocol from thigh to ankle with Doppler at selected sites should be ordered. This approach is recommended by the Society of Radiologists in Ultrasound Consensus Conference, as it increases the diagnosis of calf DVT and provides better data to explain the presenting symptoms 1. The use of a comprehensive duplex ultrasound protocol is achievable with standard ultrasound equipment and personnel, and it enhances patient safety and clinicians’ confidence.
When ordering the ultrasound, it is essential to specify the type of examination, such as "lower extremity venous duplex ultrasound," and indicate which leg is symptomatic. The primary diagnostic criterion is vein incompressibility, as normal veins collapse completely when compressed with the ultrasound probe, while veins containing thrombi remain partially or completely incompressible.
Key benefits of this approach include:
- Increased diagnosis of calf DVT
- Better explanation of presenting symptoms
- Enhanced patient safety
- Improved clinicians’ confidence
- Non-invasive procedure
- No use of radiation or contrast agents
- Can be performed quickly at bedside if needed
- Allows direct visualization of the thrombus
The comprehensive duplex ultrasound protocol is preferred over other imaging modalities, and its adoption will minimize underdiagnoses of proximal DVT, as recommended by the Society of Radiologists in Ultrasound Consensus Conference 1.
From the Research
Ultrasound Options for Suspected Deep Vein Thrombosis (DVT)
- The preferred ultrasound technique for diagnosing DVT is duplex and color Doppler sonography (DUS) 2, which has a high sensitivity and specificity for proximal DVT.
- Compression ultrasound (CUS) is also a highly effective method for diagnosing DVT, with high accuracy, ease of use, and a safe profile 3.
- CUS is considered the first-line imaging modality for DVT diagnosis and is recommended for use in various clinical settings, including emergency departments and intensive care units 3.
Specific Ultrasound Techniques
- Duplex ultrasound (DUS) is a technique that combines Doppler ultrasound and conventional ultrasound to visualize blood flow and identify abnormalities such as clot formation 2, 3.
- Color Doppler sonography is a technique that uses color to represent blood flow, allowing for the detection of abnormalities such as thrombosis 2.
- Compression sonography with color Doppler is considered the best overall test for DVT, as it is easy to perform, less expensive than other tests, and highly reliable when done properly 4.
Clinical Applications
- Ultrasound is used to diagnose DVT in symptomatic patients, with a high sensitivity and specificity for proximal DVT 2, 3.
- Ultrasound can also be used to follow up on patients with DVT, particularly those with isolated calf vein thrombosis and contraindications to conventional anticoagulation, or those with recurrent symptoms 5.
- The combination of clinical risk assessment and D-dimer testing can be used to rule out DVT, potentially eliminating the need for duplex ultrasound in certain patients 6.