Top Tips for DVT Scans

Borsha Sarker, Clinical Specialist Sonographer - Member of BMUS Council shares her top tips for DVT Scans

1)  Win from the start! Have a B-mode preset for all your probes that has high contrast, low dynamic range and good temporal resolution to ensure that your veins “wink” when you compress and release them. The “blacker” veins stand out better from the surrounding fat and muscle. If you have to use colour Doppler, make sure the setting is optimised for sensitivity in its packet size, wall filters, smoothing and frame averaging.

2)  As you start the scan, always take a pulsed Doppler waveform in the PROXIMAL common femoral vein where it drops into the pelvis at a natural angle of 45degrees. This ensures three things; 

a. that you get a good Doppler angle to the vein

b. that you always start high enough to spot any thrombus arising from the abdominal or pelvic veins, that you might otherwise miss

c. that IF you don’t find natural phasic flow which responds to valsalva, you can go on to do an abdominal and pelvic scan to look for proximal thrombus or for a mass causing extrinsic compression of the pelvic veins!

3)  Use a curved probe for moderate or larger girth legs. To avoid missing thrombus in paired or complex femoral veins, you should be able to see the femur in cross section at the back of your image or the fibula in the calf. If you can’t or are struggling, change your probe! When you apply probe compression in cross section, keep an eye on the long bone. Deeper veins may only become apparent as you start to compress!

4)  Always use an approach or window that brings the deep veins in line with the long bones when you apply compression in transverse section. This makes the compression more effective and avoids false positives.

5)  When scanning the arm for DVT, start with the ipsilateral IJV in the neck. If it’s positive for thrombus, then check the contralateral IJV. If that is also positive, you will almost certainly be looking at SVC thrombosis in the context of a patient with a swollen arm. If both IJVs are negative, start with the easier and more accessible veins in the arm and move to check the more technically difficult axillary vein last.