Contrast-enhanced ultrasound detection of a longitudinal fissure-like intraplaque channel associated with plaque-fragment embolization during carotid artery stenting: a case report

Background Vulnerable carotid plaques with fibrous-cap discontinuity, intraplaque hemorrhage, or an exposed necrotic core may release debris during carotid artery stenting (CAS). Contrast-enhanced ultrasound (CEUS) can dynamically depict plaque-surface abnormalities and intraplaque microbubble perfusion, but a longitudinal, lumen-communicating linear channel within a carotid plaque has rarely been described. Case presentation A 75-year-old man presented with 20 days of dizziness, transient syncope, blurred vision, and bilateral lower-limb weakness. B-mode and Doppler ultrasound showed a predominantly hypoechoic plaque with a thread-like, discontinuously perfused residual lumen; spectral Doppler recorded a peak systolic velocity of 367 cm/s. CEUS showed severe stenosis at the origin of the right internal carotid artery and demonstrated microbubbles entering the plaque at its proximal shoulder, traversing a continuous channel parallel to the vessel axis, and returning to the lumen through a distal opening. During CAS, immediately after stent deployment, distal flow abruptly ceased because abundant plaque debris and thrombus obstructed the embolic-protection device. Histopathology of the retrieved material showed cholesterol clefts, fibrinoid necrosis, and intraplaque hemorrhage, confirming that the embolic material contained atherosclerotic plaque rather than thrombus alone. Aspiration restored flow, and no new neurological deficit occurred. Conclusion CEUS depiction of a longitudinal, double-opening, lumen-communicating intraplaque channel may provide a preprocedural warning sign of plaque instability and embolic risk during CAS. Recognition of this morphology may support heightened embolic-protection and rescue preparedness, while prospective multimodal studies are warranted to define its reproducibility and clinical significance.