TCD and Cerebral Circulation Practice Test

Ophthalmic artery velocity is not used alone because it is affected by many factors beyond intracranial blood flow, so it cannot provide a specific, stand-alone diagnosis of intracranial perfusion.

The ophthalmic artery is a branch of the internal carotid that can participate in collateral pathways between the external and internal carotid systems. Because of this, its flow velocity can change in response to global or regional cerebral perfusion shifts, but those changes are indirect and influenced by collateral recruitment, ocular demands, systemic blood pressure, autoregulation, and vascular resistance. This means a single measurement of ophthalmic velocity may reflect perfusion alterations, but it does not reliably quantify intracranial perfusion or pinpoint stenosis on its own.

In practice, a comprehensive assessment of cerebral perfusion uses multiple vessels and modalities rather than relying on ophthalmic artery velocity alone.