In transtemporal Doppler assessment, which vessel is typically observed at a depth of 30-60 mm with antegrade flow around 55 cm/s?

• A. Middle cerebral artery
• B. Anterior cerebral artery
• C. Posterior cerebral artery
• D. Terminal internal carotid artery

Answer: (A)

In transtemporal Doppler assessment, the vessel that fits this depth and velocity is the middle cerebral artery. The temporal window commonly visualizes the MCA at about 30–60 mm beneath the skull, and in a normal study its flow is antegrade with velocities around the mid-50s cm/s, typically near 55 cm/s. This combination of accessible depth and characteristic flow makes the MCA the most reliable and commonly identified vessel in this window. The other vessels are seen less consistently at this depth and window (for example, the anterior cerebral artery tends to be more medial/deeper, and the posterior cerebral artery or terminal internal carotid often require different angles or windows), so they don’t match the given depth and velocity as routinely.