Area measurement of carotid plaque comparing B-MODE, Doppler color and contrast-enhanced ultrasound imaging

Objectives: Carotid plaque characteristic analysis are suggested to improve risk stratification. Plaque area and echolucent plaques have shown to correlate with increased risk for cardiovascular diseases. A limitation with B-mode imaging is the uncertainty that the whole plaque area is identified, primarily on echolucent plaques. Contrast-enhanced ultrasound (CEUS) is used to improve carotid imaging including better plaque area measurement. Aim: Evaluate if CEUS could improve accurate plaque area measurement compared with B-mode and Doppler color flow imaging. Methods: The study included 28 participants (50% females, mean age 58 years) with identified asymptomatic carotid plaques. We performed B-mode, Doppler color and CEUS ultrasound imaging whereas the plaque area was manually outdrawn by a single operator. Plaques were also subjectively classified as 1 echogenic, 2 echolucent, or 3 mixed plaques. Results: We did not find a significant difference in plaque area measurements between different ultrasound image modalities having all plaque types included. In the group of echolucent plaques (n= 11) we found a significant different between B-mode and CEUS (p=0.049) and also between B-mode and Doppler color imaging (p=0.039) (Illustrated in Fig 1). Conclusions: Echolucent plaque can be underestimated with B-mode imaging. Use of contrast-enhanced ultrasound should be considered in carotid plaque imaging on echolucent plaques when plaque outline is difficult to identify.