What It Is A head ultrasound is a safe and painless test that uses sound waves to make images of the brain. During the examination, an ultrasound machine sends sound waves into the head and images are recorded on a computer. The black-and-white images show the internal structure of the brain, including the ventricles (the fluid-filled cavities in the brain) and the blood vessels. Head ultrasounds are only done on babies younger than 6 months old, whose skull bones have not completely grown together (that is, they still have a soft spot on top of their head, known as a fontanel). This is because bones block the passage of ultrasound waves. The fontanel provides an opening for the sound waves to get through and reach the brain. Why It's Done Doctors order head ultrasounds when there's a concern about neurological problems in an infant. Premature babies who require intensive care frequently have head ultrasounds to rule out neurological complications of prematurity, such as bleeding in the brain (intraventricular hemorrhage, or IVH) or injury to the white matter of the brain surrounding the ventricles (periventricular leukomalacia, or PVL). A doctor also might order a head ultrasound for a baby with: an abnormal increase in head size a bulging fontanel any neurological symptoms Head ultrasounds can generally help in diagnosing: bleeding in the brain tissue or ventricles hydrocephalus (excess fluid in the brain and ventricles) a mass in the brain, such as a tumor or cyst suspected complications of meningitis Preparation You don't have to do anything special to prepare your child for a head ultrasound. You should tell the technician about any medications your child is taking before the test begins. Procedure The head ultrasound will be done in the radiology department of a hospital or in a radiology center. Parents usually can accompany their child to provide reassurance and support. If your child is in the hospital and can't easily be brought to the radiology department, a portable ultrasound machine can be brought to the bedside. This is often done in the neonatal intensive care unit (NICU). The head ultrasound can be done with the baby on his or her stomach or back, or even in a parent's arms, if necessary. The room is usually dark so the images can be seen clearly on the computer screen. A technician (sonographer) trained in ultrasound imaging will spread a clear, warm gel on your child's scalp (over the fontanel). This gel helps with the transmission of the sound waves. The technician will then move a small wand (transducer) over the gel. The transducer emits high-frequency sound waves and a computer measures how the sound waves bounce back from the head. The computer changes those sound waves into images to be analyzed. Sometimes a doctor will come in at the end of the test to meet your child and take a few more pictures. The procedure usually takes 15-30 minutes. What to Expect The head ultrasound test is painless, though your child may feel a slight pressure on the head as the transducer is moved. The gel may feel a little cold and wet. Getting the Results A radiologist (a doctor who's specially trained in reading and interpreting X-ray and ultrasound images) will interpret the ultrasound results and then give the information to your doctor, who will discuss the results with you. If the test results appear abnormal, your doctor may order further tests. In an emergency, the results of an ultrasound can be available quickly. Otherwise, they're usually ready in 1-2 days. In most cases, results can't be given directly to the patient or family at the time of the test. Risks No risks are associated with a head ultrasound. Unlike X-rays, radiation isn't involved with this test. Helping Your Child Babies sometimes cry in the ultrasound room, especially if they're restrained, but this won't interfere with the procedure. You can feed your baby, or offer a pacifier or favorite toy for comfort. If You Have Questions If you have questions about the head ultrasound, speak with your doctor. You can also talk to the technician before the exam. Back to Articles Related Articles Meningitis Meningitis is treatable, but can be serious. So it's important to know the symptoms, and get medical care right away if you think that your child has the illness. Read More Head Injuries Head injuries can be external or internal. Learn more about both kinds, how to prevent them, and what to do if your child is injured. Read More Brain Tumors Brain tumors are the second most common group of childhood cancers. Treatment requires a very specialized plan involving a team of medical specialists. Read More Hydrocephalus Often called "water on the brain," hydrocephalus can cause babies' and young children's heads to swell to make room for excess cerebrospinal fluid. Learn how this condition is managed. Read More Note: All information is for educational purposes only. For specific medical advice, diagnoses, and treatment, consult your doctor. © 1995-2021 KidsHealth®. All rights reserved. Images provided by The Nemours Foundation, iStock, Getty Images, Veer, Shutterstock, and Clipart.com.