Test Overview

Cranial
ultrasound uses reflected sound waves to make
pictures of the brain and its inner fluid chambers (ventricles). Cerebrospinal fluid flows through these chambers.

This test is most
commonly done on babies. It checks for problems from premature birth. It may be used to check problems in the brain and
ventricles in babies up to about 18 months old.

Ultrasound waves can’t pass through bones. So an
ultrasound to check the brain can’t 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 it can be done on adults after the skull has
been opened with surgery. In
adults, the test may be done to see brain masses during brain
surgery.

Cranial ultrasound for babies

The test looks for possible problems of
premature birth, such as:

  • Periventricular leukomalacia (PVL). PVL is a condition in which the
    brain tissue around the ventricles is damaged. This may be caused by a lack of oxygen
    or blood flow to the brain that may have occurred before, during, or after
    birth.
  • Bleeding in the brain. This includes intraventricular hemorrhage (IVH).

IVH and PVL increase a baby’s risk of having disabilities. These may range from mild learning or motor skill 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 often happens in the first 3 to 4 days after birth. Most
cases of IVH can be found with cranial ultrasound by the first week after
birth. But PVL can take several weeks to detect. If PVL
is suspected,
cranial ultrasound may be repeated 4 to 8 weeks after the birth. Several of these tests may be done to check areas in
the brain.

Cranial ultrasound may also be done to
check a baby’s large or increasing head size. The test can also check for infection in or around
the brain (such as from
encephalitis or
meningitis). Or it may check for brain problems that are
present from birth (such as
congenital hydrocephalus).

Cranial ultrasound for adults

Cranial ultrasound
may be done on an adult to help find a brain mass. Because the test can’t be done after the skull bones have fused, it is only done after the
skull has been opened during brain surgery.

Why It Is Done

In babies, cranial ultrasound usually is done:

  • As part of routine tests in premature babies. The test is used to find bleeding in the brain, such as intraventricular
    hemorrhage (IVH).
  • To look for any problems or to look for
    periventricular leukomalacia (PVL).
  • To screen for brain problems that may be present
    from birth. For example, it may look for congenital hydrocephalus.
  • To check a head that may be growing too large.
  • To look for infection or abnormal growths in or
    around the brain.

In adults, the test may be done during brain
surgery to help find a brain mass.

How To Prepare

You don’t need to do anything special to prepare for this test.

If an older baby is having the test, it
may help if the baby is a little hungry. You can feed your baby during the
test. This may help calm your baby so he or she will hold still during the
test.

How It Is Done

This test is done by a doctor who is an expert in imaging tests (radiologist). Or it may be done
by an ultrasound technologist (sonographer) who works along with a radiologist.
For a baby, the test may be done at the baby’s bedside in the
neonatal intensive care unit (NICU).

Your baby will lie on his or her back.
The transducer is moved across the soft spot on top of the head.
This spot is called the fontanelle. You may be asked to hold your baby during the test. Pictures of the brain and
inner fluid chambers (ventricles) can be seen on a video screen.

For an adult, the test is done during brain surgery to help
find a brain mass.

The test usually takes 15 to 30
minutes.

How It Feels

The test usually doesn’t cause discomfort. The gel used for the test may feel cold on the skin unless it is warmed first.

Risks

There are no known risks for this test.

Results

Cranial
ultrasound uses reflected sound waves to make
pictures of the brain and its inner fluid chambers (ventricles).
Cerebrospinal fluid flows through these chambers.

Cranial ultrasound

Normal:

The size and shape of the brain look
normal.

The size of the brain’s inner fluid
chambers (ventricles) is normal.

Brain tissue looks normal. There are no signs of bleeding,
suspicious areas (lesions), abnormal growths, or infection.

Abnormal:

Bleeding in the brain may be present. This
may be a sign of intraventricular hemorrhage (IVH). The test may be repeated to keep track of the bleeding or to look for problems caused by the
bleeding.

Suspicious areas or lesions around the
brain’s ventricles may be seen. This may be a sign of periventricular
leukomalacia (PVL).

The brain and ventricles may be enlarged
from the buildup of too much cerebrospinal fluid (CSF). This may
be a sign of
hydrocephalus.

Abnormal growths may be present. This may
be a sign of a tumor or
cyst.

Suspicious findings may be present. This
may be a sign of
encephalitis or
meningitis.

What Affects the Test

You or your baby may not be able to have the test, or the results may not be helpful, if:

  • The baby does not stay still during the
    test.
  • There is an open wound or recent surgical wound in the area
    being viewed.

What To Think About

  • Ultrasound can’t go through bone,
    so cranial ultrasound can be done only on babies whose skull (cranial) bones
    have not yet grown together. But duplex
    Doppler ultrasound can be done to check blood flow
    in the brain in children and adults. To learn more,
    see the topic
    Doppler Ultrasound.
  • Periventricular
    leukomalacia (PVL) usually can’t be found until several weeks after birth.
    For this reason, cranial ultrasound is generally done 4 to 8 weeks
    after birth. Cranial ultrasound may find suspicious areas in the
    brain that may or may not be PVL. Because of this, ultrasound testing may be repeated over
    several weeks. Babies with PVL or intraventricular hemorrhage (IVH) may develop
    normally. Or they may have disabilities. These include
    cerebral palsy and intellectual disability.
  • MRI
    scanning may be done instead of cranial ultrasound to evaluate PVL or IVH in premature
    babies. To learn more, see the topic
    Magnetic Resonance Imaging (MRI) of the Head.

References

Other Works Consulted

  • 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.

Credits

ByHealthwise Staff
Primary Medical Reviewer Kathleen Romito, MD – Family Medicine
Adam Husney, MD – Family Medicine
Specialist Medical Reviewer Howard Schaff, MD – Diagnostic Radiology

Current as ofOctober 9, 2017