B-flow ultrasound imaging of intraplaque blood flow in patients with carotid artery stenosis

Purpose: Intraplaque neovascularization is reportedly associated with plaque progression and instability. We aimed to determine whether intraplaque blood flow (IPBF) could be visualized without contrast medium using B-flow ultrasound imaging, and to evaluate the relationship between IPBF and ultrasound findings or clinical significance. Methods: We investigated IPBF in 66 carotid arteries with ≥ 30% area stenosis using B-mode ultrasound imaging with a Logiq s8 ultrasound system (GE) and a linear probe (9L). We assessed characteristics such as signal intensity and plaque uniformity, as well as their relationships with IPBF. Results: We visualized IPBF in 20 funicular and linear lesions with either a straight or a tortuous course. Among them, IPBF was connected with the outside of the vessel in 4 lesions, with the vascular lumen in 4 lesions, and with both sides in 9 lesions. Twenty lesions with IPBF had hypoechoic and heterogeneous plaques more frequently than 46 lesions without IPBF. Lesions with IPBF were symptomatic relatively compared with those without IPBF. Conclusion: B-flow ultrasound imaging could detect IPBF without contrast medium. IPBF was observed more frequently in hypoechoic and heterogeneous plaques, and lesions with IPBF were symptomatic relatively, therefore seemed to indicate plaque instability.