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Figure 1 Conventional ultrasound image and integrated backscatter (IB) image from the carotid artery at the same lesion. (A) Note that the intima and media are anatomically separated using conventional ultrasound imaging, as shown by the arrow. (B) Integrated backscatter values are measured at the region of interest placed in the plaque, as shown by a square, using the IB image. (C) Anterior arterial wall with an angle span of 120° between –60° and +60° were excluded from the IB evaluation because of the erratic diffraction phenomena and the influence of angle dependency. That is, the evaluation of IB values of the arterial wall was performed in the posterior wall with the exception of the anterior wall. Also, IB values of arterial lumen were measured just above posterior wall as shown by *. 2DE = two-dimensional echo.