LIQUID-CRYSTAL THERMOGRAPHY AND DUPLEX IN THE PREOPERATIVE MARKING OFVARICOSE-VEINS

Objective: To determine the role of liquid crystal thermography (LCT) in preoperative marking of varicose veins and incompetent perforating veins. Design: Single patient group study comparing techniques. Settin g: Teaching hospital vascular laboratory. Patients: Two hundred patien ts (265 legs) referred to St Mary's Hospital Vascular Laboratory for p reoperative varicose vein marking. Methods: Patients were studied usin g LCT and duplex ultrasonography to identify calf perforating veins. R esults: In part I of the study LCT identified 47 'areas at risk', 42 o f which were demonstrated to contain incompetent perforating veins on duplex examination (positive predictive value 89%). Thirty-eight of th ese 42 patients were explored at operation and 36 (95%) were confirmed as incompetent. The remaining two perforating veins could not be loca ted. In part II of the study LCT identified 327 'areas at risk', 299 o f which were demonstrated to contain incompetent perforating veins on duplex examination (positive predictive value 91%). Conclusion: LCT is useful in the identification of incompetent perforating veins, it is easy to perform, less time consuming, cheaper and can replace duplex s canning.