External validation of the Canadian CT Head Rule and the New Orleans Criteria for CT scanning in patients with minor head injury

Context  Two decision rules for indications of computed tomography (CT) in patients with minor head injury, the Canadian CT Head Rule (CCHR) and the New Orleans Criteria (NOC), suggest that CT scanning may be restricted to patients with certain risk factors, which would lead to important reductions in the use of CT scans. Objective  To validate and compare these 2 published decision rules in Dutch patients with head injuries. Design, Setting, and Patients  A prospective multicenter study conducted between February 11, 2002, and August 31, 2004, in 4 university hospitals in the Netherlands of 3181 consecutive adult patients with minor head injury who presented with a Glasgow Coma Scale (GCS) score of 13 to 14 or with a GCS score of 15 and at least 1 risk factor. Main Outcome Measures  Primary outcome was any neurocranial traumatic finding on CT scan. Secondary outcomes were neurosurgical intervention and clinically important CT findings. Sensitivity and specificity were estimated for each outcome for the CCHR and the NOC, using both rules as originally derived and also as adapted to apply to an expanded patient population. Results  Of 3181 patients with a GCS score of 13 to 15, neurosurgical intervention was performed in 17 patients (0.5%); neurocranial traumatic CT findings were present in 312 patients (9.8%). Sensitivity for neurosurgical intervention was 100% for both the CCHR and the NOC. The NOC had a higher sensitivity for neurocranial traumatic findings and for clinically important findings (97.7%-99.4%) than did the CCHR (83.4%-87.2%). Specificities were very low for the NOC (3.0%-5.6%) and higher for the CCHR (37.2%-39.7%). The estimated potential reduction in CT scans for patients with minor head injury would be 3.0% for the adapted NOC and 37.3% for the adapted CCHR. Conclusions  For patients with minor head injury and a GCS score of 13 to 15, the CCHR has a lower sensitivity than the NOC for neurocranial traumatic or clinically important CT findings, but would identify all cases requiring neurosurgical intervention, and has greater potential for reducing the use of CT scans.