Delayed Cortical Hyperperfusion Induced by Positional Carotid Compression in Stylocarotid Syndrome: A Case Report

Cortical hyperperfusion is commonly discussed in the context of cerebral hyperperfusion syndrome after carotid revascularization; however, hyperperfusion-related cortical injury may also occur after transient ischemia. A 76-year-old man developed a recurrent impaired consciousness and left hemiparesis 18 days after cervical laminoplasty. Although the initial imaging was normal, delayed cortical diffusion abnormalities with concordant hyperperfusion on arterial spin labeling emerged despite preserved arterial patency. Computed tomography revealed a markedly elongated right styloid process (78 mm) that caused positional compression of the internal carotid artery during neck flexion. Embolic and epileptic mechanisms were considered unlikely. Blood pressure control was followed by radiological and clinical improvements. This case suggests that stylocarotid syndrome may be a potential trigger for hyperperfusion-related cortical injury.