Hopkins Team Reduces Pediatric CT Dosages

A team of pediatric neurosurgeons and neuroradiologists at the Johns Hopkins Children’s Center has developed a way to minimize dangerous radiation exposure in children with a condition that requires repeat CT scans of the brain.


A team of pediatric neurosurgeons and neuroradiologists at the Johns Hopkins Children’s Center has developed a way to minimize dangerous radiation exposure in children with a condition that requires repeat CT scans of the brain. The experts say they reduced exposure without sacrificing the diagnostic accuracy of the images or compromising treatment decisions.

The approach, described ahead of print in a report in the Journal of Neurosurgery, calls for using fewer slices of the brain taken by CT scanners ¯ seven instead of the usual 32 to 40 slices. The approach, the study found, reduced radiation exposure by an average of nearly 92 percent per patient compared with standard head CT scans, while still rendering the images diagnostically accurate.

The research involved analysis of CT scans of patients with hydrocephalus. The investigators compared two standard CT scans with two limited-slice, low-dose CT scans for each one of 50 children, ages 17 and younger, treated for hydrocephalus over five years at Johns Hopkins Children’s Center. The standard CT scan images were performed prior to the launch of the new radiation-minimizing protocol.

In all 50 patients, the radiation-minimizing technique produced clear and 100-percent accurate images of the brain ventricles. When capturing changes in ventricle size, however, the low-dose approach resulted in a 4 percent error rate: Two of the 50 images were visually ambiguous, generating confusion among the clinicians who reviewed them.

There were no false negatives in the low-dose images, but three false positives, the study showed. On balance, the radiation-minimizing approach was clearly adequate, the researchers say, and would have not compromised treatment outcomes.

The Hopkins team says the radiation-minimizing technique could be especially valuable in pediatric emergency rooms, where the need for quick diagnosis precludes the use of more cumbersome, radiation-free imaging alternatives like MRI. It also can be used for routine evaluation in smaller community hospitals that may lack MRI equipment, the researchers say.

“The traditional thinking has been that fewer slices would, by definition, mean less clarity and less accuracy, rendering a CT scan suboptimal, but our findings show otherwise,” lead investigator Jonathan Pindrik, M.D.,chief neurosurgery resident at Johns Hopkins, said in a statement accompanying the study's publication.

 

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