Computed tomography and magnetic resonance imaging of mild head injury - Is it appropriate to classify patients with Glasgow Coma Scale score of 13 to 15 as "mild injury"?

Objective. The purpose of this study is to examine the relation between Glasgow Coma Scale (GCS) score and findings on computed tomography (CT) and magnetic resonance (MR) imaging of patients with mild head injury presenting GCS scores between 13 and 15. Methods. Data were collected from all consecutive patients with mild head injury who were referred to our hospital between July I and October 31, 1999. All patients were recommended to undergo CT and MR imaging examinations. Patients younger than 14 years of age were excluded. Results. Ninety patients were recruited into this study. CT. scans were obtained in 88 patients and MR imaging were obtained in 65 patients. Of these 90 patients, 2 patients scored 13 points, 5 scored 14 points and 83 (92.2%) 15 points. Patients with GCS score of 13 points demonstrated parenchymal lesions on both CT and MR imaging. Those with 14 points revealed absence of parenchymal abnormality on CT, but presence of parenchymal lesions on MR imaging. Patients in advanced age (chi square test, p < 0.0001), and those with amnesia (p = 0005, not significant), although scoring 15 points, revealed a tendency to abnormal intracranial lesions on CT scans. Conclusion: It is doubtful whether patients with GCS score 13 should be included in the mild head injury category, due to obvious brain damage on CT scans. MR imaging should be performed on patients with G-CS score 14, since the parenchymal lesions are not clearly demonstrated on CT scans. Even if patients scored GCS 15, patients with amnesia or of advanced age should undergo CT scans at minimum, and MR imaging when available.