Validation of the ECHS non trauma cranial CT rule in Australia: A prospective cohort study

Computed tomography (CT) is a commonly used imaging modality in Emergency Departments (EDs), however its use is questionable in many low yield settings. The Emergency CT Head score (ECHS) is a recently published clinical tool that assists in stratifying the need for CT brain (CTB) for patients presenting without a history of trauma. We sought to validate this tool in an Australian ED setting.

We prospectively evaluated 412 patients who received CTB without a history of trauma at a large Australian ED. We assessed them for the 4 main ECHS data points: focal neurological deficit on physical examination, new acute onset headache, transient neurological deficit, and a combination of new onset seizures with an altered conscious state. We examined their association with acute and chronic CTB findings. We then applied the ECHS to our data, calculating its sensitivity and its appropriateness at this single site via the calculation of a receiver operating curve (ROC).

10.2% of all CTB performed were positive for an acute or chronic abnormality. Only sex (male) and focal motor deficit were independent predictors of positive CTB at univariate analysis. The ECHS did not perform as anticipated in our population, with a ROC area under the curve of 0.498. An ECHS score of >0, which has been proposed as the threshold to not require imaging, had sensitivity of only 83.3% in our population.

Further research and validation is required in order to safely implement the ECHS clinical score in the Australian ED setting.