Light reflection rheography: a simple noninvasive screening test for deep vein thrombosis

Area of Science:

• Vascular Medicine
• Diagnostic Imaging
• Medical Technology

Background:

• Clinical diagnosis of deep vein thrombosis (DVT) is often unreliable.
• Contrast phlebography (CP) is the gold standard but invasive.
• Duplex ultrasonography is accurate and noninvasive but costly and time-consuming.

Purpose of the Study:

• To evaluate light reflection rheography (LRR) as a reliable, inexpensive, and noninvasive bedside screening tool for DVT.
• To assess the accuracy of LRR in comparison to contrast phlebography.

Main Methods:

• LRR uses infrared light to measure blood volume changes in the epidermis, reflecting venous emptying.
• The method was applied to the calf muscle pump to assess lower limb venous hemodynamics.
• Sixty-nine limbs in 61 patients with suspected DVT were tested with LRR within 24 hours of contrast phlebography.

Main Results:

• LRR demonstrated a sensitivity of 96.4% and a specificity of 82.9% for DVT diagnosis.
• A positive predictive value of 79% and a negative predictive value of 97.1% were achieved.
• The criteria for a positive LRR test for DVT was a venous emptying rate of 0.35 or less.

Conclusions:

• LRR is a simple, inexpensive, and noninvasive bedside test, taking only 10 minutes to perform.
• The test is highly sensitive and has a high negative predictive value, effectively ruling out DVT.
• LRR appears to be an appropriate screening test for patients with clinically suspected DVT, reducing the need for more costly studies.