At present in the United Kingdom a number of different criteria are used to grade disease in carotid ultrasound investigations. One main cause of this has been the difference in the method of grading angiograms used in the NASCET and ECST large carotid surgery trials. It is desirable that all centres reporting carotid ultrasound investigations report to the same standard. This paper presents recommendations for the reporting of ultrasound investigations of the extra cranial arteries produced by a Joint Working Group formed between the Vascular Society of Great Britain and Ireland, and the Society for Vascular Technology of Great Britain and Ireland. The recommended criteria are based on the NASCET method of grading carotid bulb disease. Key recommendations include recording peak systolic velocity (PSV) and end-diastolic velocity (EDV) in both internal and distal common carotid arteries; measuring all velocities at a Doppler angle of 45-60 degrees; the use of internal carotid PSV of >1.25 ms(-1) and >2.3 ms(-1) and a Peak Systolic Velocity Ratio of >2 and >4 to indicate >50% and >70% stenosis respectively; and the use of the St Mary's Ratio to grade >50% stenoses in deciles. General recommendations are also given for the acquisition, interpretation and reporting of the data.

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BackgroundShear Wave Elastography (SWE) imaging is a novel ultrasound technique for quantifying tissue elasticity. Studies have demonstrated that SWE is able to differentiate between diseased and normal tissue in a wide range clinical applications. However its applicability to atherosclerotic carotid disease has not been established. The aim of this study was to assess the feasibility and potential clinical benefit of using SWE imaging for the assessment of carotid plaques.MethodsEighty-one patients (mean age 76 years, 51 male) underwent greyscale and SWE imaging. Elasticity was quantified by measuring mean Young’s Modulus (YM) within the plaque and within the vessel wall. Echogenicity was assessed using the Gray-Weale classification scale and the greyscale median (GSM).ResultsFifty four plaques with stenosis greater than 30% were assessed. Reproducibility of YM measurements, quantified by the inter-frame coefficient of variation, was 22% within the vessel wall and 19% within the carotid plaque. Correlation with percentage stenosis was significant for plaque YM (p = 0.003), but insignificant for plaque GSM (p = 0.46). Plaques associated with focal neurological symptoms had significantly lower mean YM than plaques in asymptomatic patients (62 kPa vs 88 kPa; p = 0.01). Logistic regression and Receiver Operating Characteristic (ROC) analysis showed improvements in sensitivity and specificity when percentage stenosis was combined with the YM (area under ROC = 0.78).ConclusionsOur study showed SWE is able to quantify carotid plaque elasticity and provide additional information that may be of clinical benefit to help identify the unstable carotid plaque.Electronic supplementary materialThe online version of this article (doi:10.1186/1476-7120-12-49) contains supplementary material, which is available to authorized users.

There was the expected difference in AAA diameter between the two methods (0.27 cm). However, ITI wall method was measurably more reproducible.

In conclusion, SWE provides additional information on plaque stiffness which may be of clinical benefit to help identify vulnerable plaque, and warrants further study.