What is the best ultrasound order for a patient with a 2x2 hematoma of the left lower leg?

Ultrasound Order for Lower Leg Hematoma

For a 2x2 cm hematoma of the left lower leg, order a "Complete Duplex Ultrasound of the Left Lower Extremity" or "Comprehensive Lower Extremity Venous Duplex Ultrasound, Left Leg" that includes compression from the inguinal ligament to the ankle with color and spectral Doppler evaluation. 1, 2, 3

Recommended Ultrasound Protocol

The comprehensive duplex ultrasound protocol should include:

• Compression ultrasound at 2-cm intervals from the common femoral vein through the popliteal vein down to the ankle veins 1, 3
• Color Doppler imaging to assess venous filling patterns 2, 3
• Spectral Doppler waveforms of the common femoral veins and popliteal veins 2, 3
• Evaluation of both deep and superficial venous systems 1, 4

This comprehensive approach is superior to limited protocols because it will simultaneously evaluate for DVT (which can present with leg swelling mimicking hematoma) while also directly visualizing the hematoma itself. 1, 5

Why This Specific Order Matters

A complete duplex examination detects multiple pathologies beyond just DVT:

• Hematomas are directly visualized as soft tissue masses on ultrasound 4, 5
• The examination can differentiate between hematoma, Baker's cyst, muscular rupture, or venous thrombosis—all of which can present with similar clinical findings 6, 4
• Limited protocols examining only thigh-to-knee miss calf pathology and require repeat studies in 5-7 days 3
• Studies show that 6.4% of lower extremity ultrasounds detect masses (including hematomas), and limiting the examination would miss these findings 5

Clinical Context for Ordering

Before ordering the ultrasound, assess pretest probability for DVT using the Wells score, as hematomas can coexist with or mimic DVT:

• If the patient has low pretest probability for DVT (<15%), you can proceed directly to ultrasound or obtain a high-sensitivity D-dimer first 1, 2, 3
• If moderate or high pretest probability (≥15%), proceed directly to the comprehensive duplex ultrasound without D-dimer 1, 2

The hematoma itself may be causing localized tenderness and swelling, which are components of the Wells score, so clinical judgment is essential. 1

Common Pitfalls to Avoid

Do not order a "limited" or "two-point compression" ultrasound:

• Limited protocols only examine the femoropopliteal segment and would miss calf vein pathology where your hematoma is located 3, 5
• A limited examination detecting only proximal DVT would miss 4.06% of acute calf DVTs and 15.27% of superficial venous thromboses 5

Ensure the order specifies "left lower extremity" and includes the calf region:

• The 2x2 cm hematoma location in the lower leg requires examination of the calf veins and surrounding soft tissues 4, 5
• Compression at 2-cm intervals throughout the examination is necessary to detect both the hematoma and any associated venous pathology 3