Thermal imaging in the investigation of deep venous thrombosis

Preliminary assessment of clinically suspected deep venous thrombosis (DVT) of the lower limb by thermography avoids the need for over one third of venograms or duplex Doppler ultrasound scans. Clinical diagnosis of DVT is notoriously unreliable-hence the need for an accurate means of clinical investigation. Untreated DVT is dangerous as it can progress to pulmonary embolism (PE) which is frequently fatal or life-threatening. Treatment of DVT by anticoagulation poses risks of its own however, and should not be undertaken without a confirmed diagnosis. Thermal imaging is quick, simple, noninvasive, risk-free, cost-effective and highly sensitive in the initial investigation of suspected DVT; a negative thermogram excludes DVT and avoids the necessity for further investigation. Thermal imaging is, however, non-specific; a positive thermogram has a number of possible causes and is an indication for further assessment by venography or Doppler ultrasound to confirm or exclude DVT. Thermography should be considered the initial investigation of choice in clinically suspected DVT, proceeding to venography or Doppler ultrasound only when thermography is positive.