CT Scans Versus MRIs for Imaging a Child's Brain
Both CTs and MRIs come with risks — from sedative drugs to levels of radiation. Depending on the severity of brain injury, parents and doctors should always consider the risk-benefit ratio.
See more videos with Dr. Rachel Berger.
Head CTs are based on radiation, so you need to irradiate the brain in order to do a head CT. There's been a lot of concern about are we irradiating too many children for head CT's. There's a lot of concerns about head CT-- first, because if you're young, you have more time to develop a cancer that could be related to radiation because you're going to live longer than an adult. There are other issues with the fact that the young brain may actually be more vulnerable to the effects of radiation than an older person's brain. And then we have a lot of issues--and this is probably the most important one, although overlooked a lot--is that the radiation dose given in a pediatric hospital is often as much as 5 times lower than the dose of the same CT scan in an adult hospital. And most children are actually getting CT scans in adult hospitals not pediatric hospitals. And so I think there are a lot of things that we have to think about. What are the risks of radiation? But of course, what is the benefit? A radiologist I work with said, "It doesn't matter how much radiation you didn't get if you're dead." Clearly we do need to think about the risks, but sometimes we do need to image the brain. The one thing that parents have control over is where you're getting that head CT. If you're in an adult hospital and they're going to transfer the child anyway, wait to get that head CT until you go to the pediatric hospital unless you know for sure that they're using pediatric dosing on the CT scanner. And I think parents asking, "Do I really need this?" is always a good question to ask. Hopefully, most physicians are only doing it if you need it. Unfortunately, a lot of people looked at the brain MRI as the answer to not irradiating, and there are problems with the brain MRI. We need to sedate children. They can't lie still for an hour. So, you need an IV in a lot of cases. You need to give them drugs in order to sedate them, and there is a lot of controversy about whether these drugs are dangerous to the developing brain, and some of the animal models of these drugs that we give are very concerning--particularly for the young brain-- and so I don't think MRI is the answer. MRI also doesn't detect some acute types of bleeding in the brain. And it also doesn't detect skull fractures, so it's good for some things, but it's not an answer to the head CT. So again, there's risk, there's benefit, and that's something that hopefully physicians have thought about, and families can bring up to physicians if they have questions.
Posted on BrainLine January 9, 2013.
Produced by Victoria Tilney McDonough and Jared Schaubert, BrainLine, and Dan Edblom.
Rachel Berger MD, MPH is part of the Child Advocacy Center at Children’s Hospital of Pittsburgh and a member of the hospital’s Child Protection Team. She has been involved in the evaluation of thousands of children with suspected child abuse and neglect.