Abstracts S41

with US as a deep thick hypoechoic band. Ganglion cysts arising in closeproximity to the cruciate ligaments can be occasionally identified with USas incidental findings. A rare tendon-related pathology of the posteriorknee is the popliteal artery entrapment syndrome. This syndrome is relatedto compression of the popliteal artery secondary to the anatomic relation-ships between the vessel and an abnormal medial head of the gastrocne-mius or popliteus. When examining the distal biceps femoris, US scanningshould be extended cranially to include the musculotendinous junction asit is a common site of sport-related injuries.

0315

Sonographic Assessment of Lower Limb Arterial Calcification –? Novel Marker for Predicting Diabetic ComplicationsKin Hung Liu, Prince of Wales Hopsital, The Chinese University ofHong Kong, Hong KongChiu Wing Chu, Prince of Wales Hopsital, The Chinese Universityof Hong Kong, Hong KongPik San Kong, The Chinese University of Hong Kong, Hong KongWai Sang Chan, Prince of Wales Hopsital, Hong KongChing Wan Ma, The Chinese University of Hong Kong, Hong KongWing Yee So, The Chinese University of Hong Kong, Hong KongChun Yip Tong, The Chinese University of Hong Kong, Hong KongChung Ngor Chan, The Chinese University of Hong Kong, Hong Kong

Objective: Lower limb arterial calcification (LLAC) detected on softtissue radiograph is a strong predictor of various diabetic complications.Ultrasound is sensitive to detect arterial calcification, but no previousstudies investigated its use in detecting LLAC. The aims of this study wereto compare the sensitivity of ultrasound and plain radiographs to detectLLAC, and to investigate its relationships with diabetic complications.Methods: Eight-three Chinese diabetic patients (mean age�59 years,M:30, F:53) were recruited. All subjects had clinical and laboratory testsfor determining diabetic complications, and had ultrasound examination ofsuperficial femoral arteries of both thighs to determine the presence ofLLAC which were graded into 0,1,2,3,4 in each limb according to itsseverity. The sum of grading from both thighs was used for analysis. Allpatients also had soft tissue radiographs of both thighs taken.Results: 58% of subjects had LLAC detected on ultrasound while 27%had calcification detected on plain radiographs. Only one subject(1.2%) had calcification detected on plain radiograph but not ultra-sound. Chi-Square test showed that the presence of moderate / severecalcification (grade 5 or above) was related to various diabetic com-plications including peripheral vascular disease (p�0.02), diabetic ret-inopathy (p�0.03), nephropathy (p�0.06), neuropathy (P�0.01), andmyocardial infarction (p�0.01).Conclusion: Preliminary results showed that ultrasound is more sen-sitive than plain radiograph to detect LLAC, and higher-grade LLACdetected on ultrasound was related to various diabetic complications.Sonographic assessment of LLAC may potentially be a novel markerfor identifying diabetic subjects at risk for serious complications.

0316

Ultrasound Assessment of Endothelial Function with Flow-Mediated Vasodilatation of the Brachial ArteryPenny S P Koh, Baker IDI Heart and Diabetes Institute, Australia

Introduction: Brachial artery ultrasonography non-invasively mea-sures Flow-Mediated Dilatation (FMD), a marker of endothelial func-tion. FMD measurement may be useful clinically in diabetes andcardiovascular disease.Objective: To evaluate precision of FMD measurements performed inour laboratory.Method: 50 FMD studies were performed on healthy volunteers.

Subjects fasted overnight, withheld morning vasoactive medications,

refrained from vigorous exercise, and rested for 20 min before FMDtesting. The brachial artery was imaged above the antecubital fossa ata position showing the optimal vessel image. Reactive hyperaemia wasinduced with a 5 min inflation of a forearm pressure cuff Ultrasoundimages were acquired in 10 heart-cycle cineloops from time of cuffrelease until 90s after. Maximum FMD% changes were analysed usingBrachial Analyzer software. After 10 mins rest, endothelium-indepen-dent vasodilation was measured using nitroglycerine. Repeat studieswere performed on 10 subjects � 1 week apart. Data are mean � SD.Intra-observer reproducibility was assessed by (a) mean � SD of thedifference between both scans of each patient analysed by one ob-server; (b) coefficient of variation (CV); (c) intraclass correlationcoefficient (ICC) and (d) Bland-Altman plot.Results: The mean FMD was 8.54 � 3.0%. The mean difference inFMD for scans done on different days by the same observer was 0.57 �0.79%. The CV was 7.8%. ICC was 0.96. Points on the Bland-Altmanplot fell within 95% limits of agreement.Conclusion: Good reproducibility of FMD% change was achieved.This means that FMD is useful for assessing endothelial function in ourfuture clinical trials.

0318

Importance of Bypass Graft Surveillance in 2009Philip Walker, University of Queensland, Department of VascularSurgery, RBWH, Australia

The aims of peripheral arterial revascularisation are to heal wounds,salvage the limb and to ameliorate claudication. Postoperatively the aim isto keep the bypass patent. Significant structural defects will occur in almostone third of infra-inguinal bypasses (most within 6-9 months) and most ofthese defects will be due to intimal hyperplasia. A variety of methods havebeen advocated to identify graft defects so that they can be repairedpreemptively so as to prevent graft failure. These methods include intra-operative assessment with angiography, duplex, angioscopy, or flow mea-surement; clinical evaluation with or without ABI assessment and claudi-cation exercise testing; impedance analysis; duplex ultrasound graft sur-veillance and angiography, CTA or MRA for selected cases. Theconventional wisdom has been that the patency of bypass grafts can besignificantly prolonged if developing graft lesions are identified and cor-rected before graft thrombosis and thus limb salvage can be improved. Ithas been accepted that duplex surveillance is mandatory and the expenseis justified. Two randomised studies in the 1990s comparing duplexsurveillance with “clinical follow-up” provided conflicting results. Mostrecently the Vein Graft Surveillance Trial (2005) concluded that intensivesurveillance with duplex does not improve limb salvage, bypass graftpatency, or QOL scores, but comes with a significant additional cost. Thishas resulted in a rethink by clinicians with renewed focus on identifyingclinical and early duplex features that might allow the identification of“high risk grafts” that require more rigorous clinical and duplex surveil-lance compared to “low risk grafts” that could be followed with clinicalfollow-up and ABI measurement alone.This presentation will discuss the rationale for peripheral arterial bypassgraft surveillance and the evidence base that supports its current role.

0319

The Development of Array Based Ultrasound Imaging in the 10 -80 MHz RangeStuart Foster, University of Toronto, Canada

The recent development of array based micro-ultrasound in the 10 - 80MHz Range is now transforming preclinical ultrasound imaging. In thispresentation the development of micro-ultrasound instruments will bedescribed beginning with mechanical sector scanners and then ex-

tended to micro-ultrasound array systems that now operate at centre