In a transorbital Doppler exam, which vessel at 60-80 mm depth with parasellar flow and about 47 cm/s velocity is described?

• A. Posterior cerebral artery
• B. Middle cerebral artery
• C. Internal carotid artery
• D. Ophthalmic artery

Answer: (A)

In transorbital Doppler, vessels are identified by where they sit in depth and how their flow appears in that window. A depth of roughly 60–80 mm places you imaging well into the intracranial circulation, and the parasellar region is near the cavernous/supraclinoid area where posterior circulation structures become accessible in this approach. The posterior cerebral artery travels through the posterior circulation and can be visualized in this zone through the transorbital window. A measured velocity around 47 cm/s fits the typical systolic flow range for intracranial arteries like the PCA in this view, with a normal diastolic component as well. Therefore, the vessel described is the posterior cerebral artery, which best matches both the depth and the flow characteristics provided. Ophthalmic artery would be shallower and more orbitally located, while the internal carotid and middle cerebral arteries are usually accessed in different planes or depths in this window.