In venous duplex, which feature helps determine DVT when the vein does not fully collapse?

• A. Echogenicity of the thrombus
• B. Compression alone
• C. Flow pattern on color Doppler
• D. Vein diameter

Answer: (A)

When a vein doesn’t fully collapse, you still need direct evidence of clot inside the lumen. Echogenicity of the thrombus provides that evidence: you can see material within the vein that has distinct echogenic characteristics consistent with a thrombus, confirming DVT even if compression isn’t entirely successful.

Relying on compression alone can be misleading in this scenario, since factors like technique, patient habitus, or edema can make a vein appear noncompressible without a thrombus. Color Doppler flow patterns can be helpful but are not as specific—flow can be altered for several reasons and may not clearly differentiate a partial thrombus from other causes of altered flow. Vein diameter alone isn’t diagnostic because enlargement can result from nonthrombotic processes. So the presence of intraluminal echogenic material is the best indicator of DVT when full collapse isn’t achieved.