Morphological and biomechanical characteristics of carotid plaques with mild stenosis using ultrafast and high-definition ultrasonography.

OBJECTIVES

This study aimed to evaluate the efficiency of multimodal ultrasonography applied to the carotid plaque with mild stenosis as potential biomarkers of ischemic stroke.

MATERIALS AND METHODS

We consecutively enrolled patients with mild carotid artery stenosis. In addition to traditional ultrasound parameters, Young's modulus (YM), shear wave velocity (SWV), shear modulus, and strain ratio were obtained using ultrasound elastography; wall shear stress (WSS) and blood flow turbulence of plaque were obtained using high-frame-rate vector flow imaging; intraplaque neovascularization level was obtained using high-definition micro-flow imaging, and plaque volume and gray-scale median (GSM) were obtained using three-dimensional ultrasound imaging. These parameters were compared between culprit and non-culprit plaques.

RESULTS

Of the 476 patients included, 105 were symptomatic. No significant differences were observed in area, volume, velocity, morphology, echo, strain ratio, turbulence, and GSM between culprit and non-culprit plaques. Culprit plaques showed lower YM, SWV, and shear modulus but higher WSS. The peak WSS in culprit plaques exceeded that at the ascent, descent, downstream, and upstream positions. Culprit plaques also had higher neovascularization levels, with more grade 0 neovascularization in non-culprit plaques. Multivariate analysis revealed that higher maximum SWV was independently associated with non-culprit plaques, while higher peak WSS and neovascularization levels were associated with culprit plaques. The combined indicators had an area under the receiver operating characteristic curve of 0.856 for predicting culprit plaques.

CONCLUSION

Multimodal ultrasonography, including shear wave elastography, high-frame-rate vector flow imaging, and high-definition micro-flow imaging, can effectively distinguish between culprit and non-culprit carotid plaques with mild stenosis.

KEY POINTS

Question Conventional ultrasound imaging has limitations when assessing the risk of ischemic stroke in carotid plaques with mild stenosis. New ultrasound techniques need to be explored. Findings Shear wave elastography, high-frame-rate vector flow imaging, and high-definition micro-flow imaging, successfully identified specific markers differentiating culprit from non-culprit carotid plaques with mild stenosis. Clinical relevance Multimodal ultrasonography, by measuring SWV, WSS, and intraplaque neovascularization level, offers a non-invasive approach to assess carotid plaques with mild stenosis, potentially improving stroke risk prediction and guiding early intervention strategies to enhance patient outcomes.