In transtemporal Doppler, which vessel at 60-70 mm depth shows antegrade flow with about 39 cm/s velocity?

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

Answer: (D)

In transtemporal Doppler, where you sample along the temporal window, depth helps you locate the vessel and velocity helps confirm its identity. The anterior cerebral artery is commonly seen at deeper insonation depths, around 60–70 mm, and its flow is antegrade toward the brain with moderate velocities typically in the 30–50 cm/s range. A velocity of about 39 cm/s fits well with this pattern, making the anterior cerebral artery the best match for a signal at that depth showing antegrade flow.

By contrast, the middle cerebral artery is usually detected at shallower depths and tends to exhibit higher velocities, often well above 50 cm/s. The internal carotid artery in this window isn’t typically matched to that exact depth and presents with different waveform characteristics, while the posterior cerebral artery can appear at similar depths but may have different flow directions depending on insonation angle.