Graphs illustrating key results. A) Box and whisker plots showing the Greyscale median (GSM) and Young’s Modulus (YM) of plaques against subjective Gray-Weale Classification. Both values increase with higher classification of plaque appearance. B) Box and whisker plots illustrating plaque GSM and YM against the percentage stenosis, grouped into either mild (30-50%), moderate (50-70%) or severe (>70%). C) Box and whisker plots illustrating the plaque GSM and YM of symptomatic and asymptomatic plaques. D) ROC curves for the logistical regression of different ultrasound methods, and percentage stenosis as an individual method.