Why Brain Ultrasound Isn’t Used: MRI & CT Are the Standards

Ultrasound cannot image the adult brain because the skull’s dense bone reflects and attenuates sound waves, preventing penetration.

Preferred Modalities

• MRI: Superior soft‑tissue contrast; detects strokes, tumors, MS, TBI, aneurysms. No ionizing radiation.
• CT: Rapid, excellent for acute hemorrhage, fractures, hydrocephalus. Uses X‑rays; lower soft‑tissue contrast than MRI.

Exceptions

• Neonates/infants: Open fontanelles allow transcranial Doppler and cranial ultrasound.
• Intraoperative: Ultrasound used during craniotomy after bone flap removal.
• Transcranial Doppler (TCD): Assesses blood‑flow velocity in major intracranial vessels through thin temporal bone windows.

For diagnostic brain imaging in adults, MRI and CT remain the gold standards.