Ankur Thapar MBBS, MRCS, Presenter: Nothing to Disclose

Yanling Zheng, Abstract Co-Author: Nothing to Disclose

Brahman Dharmarajah MBBS,MRCS, Abstract Co-Author: Nothing to Disclose

Mike Averkiou PhD, Abstract Co-Author: Consultant, Koninklijke Philips Electronics NV Consultant, Samsung Electronics Co Ltd

Joseph Shalhoub, Abstract Co-Author: Nothing to Disclose

Alun Davies, Abstract Co-Author: Nothing to Disclose

Edward Leen MD, FRCR, Abstract Co-Author: Equipment support, Koninklijke Philips Electronics NV Equipment support, General Electric Company Equipment support, SuperSonic Imagine Research Consultant, General Electric Company Speakers Bureau, Bracco Group Speakers Bureau, Koninklijke Philips Electronics NV Speakers Bureau, AngioDynamics, Inc Speakers Bureau, General Electric Company

To identify if dynamic contrast enhanced ultrasound (DCE-US) could identify differences in intraplaque perfusion and ulceration between symptomatic and asymptomatic cerebrovascular disease patients.

Ethical approval was obtained for this prospective cross-sectional study. Sample size calculation determined 22 patients per group were required to give a 90% power and 5% false positive rate to detect a difference of 50% v 5% in generalized plaque perfusion.   Fifty-six non-consecutive patients with 50-99% stenosis and no alternative embolic source were scanned by a vascular scientist using color Doppler. Thirty were asymptomatic and 26 symptomatic. Luminal stenosis and ulceration (>1.5mm surface defect with color fill) were recorded. They were rescanned (AT) using a non-linear pulse sequence, a 2ml bolus of SonoVue™, L9-3 transducer at MI 0.06. DICOM loops were exported to a workstation for offline blinded image analysis by an independent vascular radiologist (YZ). Intraplaque perfusion was graded as generalized (>50% of plaque area) or localized (<50%) and ulceration as earlier specified. YZ was the primary reader and AT the second reader.

Generalised plaque perfusion was seen in 9/26 (35%) of symptomatic and 12/30 (40%) of asymptomatic patients. There was no significant difference between the groups (OR 0.79, 95% CI 0.27 – 2.36, p=0.78).   Ulceration was seen in 4/56 (7%) of patients with colour Doppler and 9/56 (16%) with DCE-US (p=0.24). With colour Doppler there was no significant difference in ulceration between symptomatic or asymptomatic patients (1/26 v 3/30, p=0.62). With DCE-US there was a trend towards more ulceration in symptomatic patients (7/26 v 2/30, OR 5.2, 95% CI 0.96 – 27.6, p=0.07). For plaque perfusion intra-reader reproducibility was κ=0.43 and inter-reader reproducibility κ=0.49. For ulceration on DCE-US, intra-reader κ=0.87 and inter-reader κ=0.64.

Semi-quantitative plaque perfusion measurements were subjective and did not discriminate between symptomatic and asymptomatic patients.  Further research should focus on plaque ulceration and objective quantification of plaque perfusion.

Dynamic contrast enhanced ultrasound appears to have greater potential for imaging carotid plaque ulceration than perfusion at present.  Technical improvments in quantification are required.

Thapar, A, Zheng, Y, Dharmarajah, B, Averkiou, M, Shalhoub, J, Davies, A, Leen, E, Dynamic Contrast-enhanced Ultrasound for Assessment of Perfusion and Ulceration in Carotid Plaque.  Radiological Society of North America 2012 Scientific Assembly and Annual Meeting, November 25 - November 30, 2012 ,Chicago IL. http://archive.rsna.org/2012/12022265.html