Because ultrasound cannot penetrate bone,
cranial ultrasound can be performed only on babies whose skull (cranial) bones
have not yet grown together. But duplex
Doppler ultrasound can be done to evaluate blood flow
in the brain in children and adults. To learn more,
see the topic
leukomalacia (PVL) is not usually detectable until several weeks after birth.
For this reason, cranial ultrasound is generally done 4 to 8 weeks
after delivery. Because cranial ultrasound may find suspicious areas in the
brain that may or may not be PVL, ultrasound testing may be repeated over
several weeks. Babies with PVL or intraventricular hemorrhage (IVH) may develop
normally or may have varying levels of disability, including
cerebral palsy or
an intellectual disability.
Chernecky CC, Berger BJ (2008). Laboratory Tests and Diagnostic Procedures, 5th ed. St. Louis: Saunders.
Sloan MA, et al. (2004). Assessment: Transcranial Doppler ultrasonography. Report of the Therapeutics and Technology Assessment Subcommittee of the American Academy of Neurology. Neurology, 62(9): 1468–1481. Also available online: http://neurology.org/content/62/9/1468.full.