Phlebology (1995) 10:110-114 © 1995 The Venous Forum of the Royal Society of Mesticine and Societas Phlebologica Scandinavica Original Article PHLEBOLOGY Liquid Crystal Thermography and Duplex in the Preoperative Marking of Varicose Veins E. Kalodiki, L. Calahoras, G. Geroulakos and A. N. Nicolaides Irvine Laboratory for Cardiovascular Investigation and Research, Academic Surgical Unit, St Mary's Hospital Medical School, Imperial College of Science Technology and Medicine, London W2, UK ABSTRACT Objective: To determine the ro!e of crystal mography. (LCf) in ma.rkmg of vancose veins and incompetent perforating vems, Design: Single patient group study comparing tech- niques. Setting: Teaching hospital vascular laboratory. Ptdients: Two hundred patients (265 legs) referred to.St Mary's Hospital Vascular Laboratory for preoperative varicose vein marking. Methods: Patients were studied using LCf and duplex ultrasonography to identify calf perforating veins. Results: In part I of the study LCf identified 47 'areas risk' 42 of which were demonstrated to contain inco:npetent perforating veins on examination (positive predictive value 89%). '!lllrty-eight of these 42 patients were explored at operation 36 (95%) were confirmed as incompetent. The remauung two perforat- ing veins could not be located. In part II of the study LeT identified 327 'areas at risk', 299 of which were demonstrated to contain incompetent perforating veins on duplex examination value.91%). Conclusion: LCT is useful 10 the Identification of mcom- petent perforating veins, it is easy to perform, less.time consuming, cheaper and can replace duplex scanrnng. Correspondence and offprint requests /0: Dr Evi Vascular Research Fellow, Irvine Laboratory. Academic Surgical Unit, St Mary's Hospital Medical School, Praed St, London W2 INY, UK. Keywords: Duplex ultrasonography; Incompetent,per- forating veins; liquid crystal thermography; Vancose veins Introduction Just under one-third of the population, in any country of the civilized world, suffers from primary varicose veins [1]. Each year, over 50000 patient,s are a?mitted t? British hospitals for treatment of vancose veins or their complications [2]. Cheatle et aI. [3J, in a survey on 100patients compar- ing information provided by the referring physician with the results of the duplex scan, showed that 25 patients (11 with unsuspected sapheno-popliteal junction reflux and 16 with incompetent perforators) would have had significant venous abnormalities untreated surgically had the clinician relied on clinical judgment alone. The actual contribution of the incompetent perforat- ing veins to the clinical disorder is controversial [4] and much has been written about them. Many surgeons, despite their intentions, deal inadequately with the incompetent perforating veins. The reason is that, in the calf, perforating veins usually do not pass directly the deep veins to the saphenous trunks but to. th.elf tributaries [5]. This can be one of the reasons for nnssmg them at operation. However, the most important is that the clinical detection of incompetent perforating veins is often inaccurate [3,6-10]. The sensitivity of clinical detection as compared with operative findings is at best 64% [6-11].