ultrasound uses reflected sound waves to produce
pictures of the brain and the inner fluid chambers (ventricles) through which
cerebrospinal fluid (CSF) flows. This test is most
commonly done on babies to evaluate complications of premature birth. In
adults, cranial ultrasound may be done to visualize brain masses during brain
Ultrasound waves cannot pass through bones, so an
ultrasound to evaluate the brain cannot be done after the bones of the skull
(cranium) have grown together. Cranial ultrasound can be done on babies before
the bones of the skull have grown together or on adults after the skull has
been surgically opened. It may be used to evaluate problems in the brain and
ventricles in babies up to about 18 months old.
Cranial ultrasound for babies
premature birth include periventricular leukomalacia (PVL) and bleeding in the brain, including intraventricular hemorrhage (IVH). PVL is a condition in which the
brain tissue around the ventricles is damaged, possibly from decreased oxygen
or blood flow to the brain that may have occurred before, during, or after
delivery. IVH and PVL increase a baby's risk of developing disabilities
that may range from mild learning or gross motor delays to
cerebral palsy or
an intellectual disability.
IVH is more common in premature babies than in full-term babies. When it
occurs, it most commonly develops in the first 3 to 4 days after birth. Most
cases of IVH can be detected by cranial ultrasound by the first week after
delivery. In contrast, PVL can take several weeks to detect. For this reason,
cranial ultrasound may be repeated 4 to 8 weeks after delivery if PVL
is suspected. Several cranial ultrasound tests may be done to evaluate areas in
the brain. See two newborn babies'
cranial ultrasound images .
Cranial ultrasound may also be done to
evaluate a baby's large or increasing head size, detect infection in or around
the brain (such as from
meningitis), or screen for brain problems that are
present from birth (such as
congenital hydrocephalus). See a picture of congenital hydrocephalus .
Cranial ultrasound for adults
may be done on an adult to help locate a brain mass. Because cranial ultrasound
cannot be done after the skull bones have fused, it is only done after the
skull has been surgically opened during brain surgery.