Liquid crystal contact thermography of deep venous thrombosis.

A new thermographic technique for the diagnosis of deep venous thrombosis, liquid crystal contact color thermography using naturally occurring cholesteric crystals is described. Cholesteric crystals have the property of changing colors in consistent, predictable patterns in response to local temperature changes. The technique is reliable and reproducible. It has also been rendered simple by embedding the liquid crystals in elastic, flexible sheets. The sheets are inflated and readily adapt and contour to extremities of various sizes and shapes. Preliminary results have shown excellent correlation with ascending phlebography. The two methods were in agreement in 90% of cases with no false-negative liquid crystal thermograms. The technique shows promise as a noninvasive screening study for the diagnosis of deep venous thrombosis in high risk patients.