In the United States, about half of children taken to hospital emergency departments with a head injury receive a CT scan, often in response to pressure from concerned parents.
Head CT scans use several X-rays directed at the same time from different angles to create pictures of the tissue inside the brain. They are useful for detecting brain tumours, and bleeding, such as from aneurysms and brain damage from trauma.
But because they use X-rays, every time a person has one, it slightly increases their lifetime risk of developing diseases like cancer. And because children have a longer life ahead of them, this is more significant.
A report published in 2007 in the New England Journal of Medicine that suggested that doctors underestimate the radiation risk from CT scans, and may be ordering too many of them, estimated that more than 1 million children per year in the United States are being irradiated unnecessarily.
The Pediatrics study, led by researchers from Boston Children's Hospital Boston and UC Davis, found that if children can be watched for a few hours when they come to the emergency department, they may not need a CT scan, thus avoiding the exposure to ionizing radiation.
Also, serious traumatic brain injury is uncommon, as co-lead author Dr Lise Nigrovic, of Children's Hospital Boston, told the press:
"Only a small percentage of children with blunt head trauma really have something serious going on."
Encouraging doctors to change their practice would not only save costs, but also result in better medicine, say the researchers.
Nigrovic stressed that CT isn't bad if you really need it, but you shouldn't be using it on children who are at low risk of having a significant injury.
"For parents, this means spending a couple of extra hours in the ED in exchange for not getting a CT," she explained, adding that:
"It's the children in the middle risk groups -- those who don't appear totally normal, but whose injury isn't obviously severe -- for whom observation can really help."
For the study, Nigrovic, co-lead author Nathan Kuppermann, chair of the Department of Emergency Medicine at UC Davis, and colleagues examined a subset of data from a large prospective study by the Pediatric Emergency Care Applied Research Network (PECARN).
They looked at outcomes of over 40,000 children with head trauma seen at 25 different emergency departments, of which 14% were observed before a decision about whether to send them for CT scan was made. The observation periods varied, as did the severity of the head trauma.
They found that overall, only 31% of the children placed under observation eventually had a CT scan compared to 35% who were not.
However, when they then analyzed the results according to severity of head injury and the different practices at different hospitals, the gap widened and showed that the chance of being sent for a CT scan in the observed children was about half that of the non-observed children. Also, children whose symptoms improved while under observation were less likely to be sent for a scan.
In the case of clinically traumatic brain injury, such as resulting in death, need for surgery, intubation for 24 hours or more, or admission to hospital for at least two nights, the researchers found similar rates in the observed and unobserved groups (0.75 and 0.87% respectively).
The data didn't allow the researchers to work out how long the children in this study actually spent under observation, and they would like to look at this factor more closely in a future study.
The American Academy of Pediatrics' practice guidelines suggest children be observed for 4 to 6 hours after an injury.
Kuppermann said there was a need for appropriate and safe guidelines to reduce the number of unnecessary brain CT scans on children.
"The results of this analysis demonstrate that a period of observation before deciding to use head CT scans on many injured children can spare children from inappropriate radiation when it is not called for, while not increasing the risk of missing important brain injuries," he added.
Nigrovic suggests if your child has a head injury, you should observe the following steps and points:
- Check with your family doctor or primary care health professional before you take your child to the emergency department.
- If the child has a headache, is vomiting or appears confused, or his or her symptoms get worse as time goes on, then you should take them to the emergency department.
- Be prepared for the staff at the emergency department reasonably choosing to place your child under observation for several hours before deciding whether a head CT is necessary.
- Changes in symptoms over time is an important factor in that decision.
Source: Children's Hospital Boston.