"Children assessed for cervical spine injury following blunt trauma are often evaluated by CT initially even when they are asymptomatic," a US study suggests [1].
The physicians reporting on the paper described the finding as "a matter of concern," noting that children are thought to be more sensitive to radiation than adults.
Looking at the charts of 557 children evaluated with CT at a pediatric trauma center, they found that 60 per cent did not have any focal neurologic deficit, depressed mental status or posterior neck pain on arrival at the emergency department. However, just 32 per cent underwent conventional radiography prior to CT scanning. Twenty-five true cervical spine injuries were identified in all.
The researchers used anthropomorphic phantoms to estimate the radiation dose that the thyroid gland was exposed to, reporting "a significantly higher amount of radiation from CT than from conventional radiography, even when the radiography needs to be repeated."
They estimated an excess relative risk of thyroid cancer from exposure to cervical spine CT of 0.7 in children aged five to eight years, with a corresponding excess relative risk of two in younger children. No excess risk was associated with conventional radiography.
The study authors said the cervical spine of lower risk patients can usually be cleared with conventional radiography. However, they added that their findings suggest CT is being used as the initial tool "without discrimination in terms of severity."
[1] CT versus plain radiographs for evaluation of c-spine injury in young children: do benefits outweigh risks?
Pediatr Radiol 2008; 38: 635-644
