What is the most accurate method for diagnosing thrombophlebitis of the lower leg?

• A. Impedance plethysmography
• B. Physical examination findings
• C. Doppler ultrasound
• D. Venography

Answer: (D)

Venography is considered the most accurate way to diagnose thrombophlebitis of the leg because it directly visualizes the venous lumen after contrast administration, showing filling defects where a thrombus blocks flow and allowing precise assessment of the extent and locations involved. This direct lumen imaging provides definitive evidence of thrombosis and can differentiate acute thrombus from chronic changes, making it the reference standard. In practice, though, venography is invasive and carries risks from contrast and venous access, so duplex Doppler ultrasound is now the preferred initial test due to being noninvasive, rapid, and highly effective for most suspected cases. Impedance plethysmography offers less reliable data, and relying on physical examination alone cannot confirm thrombosis.