UC Davis

The positive rate of head CT in non-trauma patients presenting to the emergency department (ED) is low. Currently, indications for imaging are based on the individual experience of the treating physician, which contributes to overutilization and variability in imaging utilization. The goals of this study are to ascertain the predictors of positive head CT in non-trauma patients and demonstrate feasibility of a clinical scoring algorithm to improve yield. We retrospectively reviewed 500 consecutive ED non-trauma patients evaluated with non-contrast head CT after presenting with headache, altered mentation, syncope, dizziness, or focal neurologic deficit. Medical records were assessed for clinical risk factors: focal neurologic deficit, altered mental status, nausea/vomiting, known malignancy, coagulopathy, and age. Data was analyzed using logistic regression and receiver operator characteristic (ROC) curves and three derived algorithms. Positive CTs were found in 51 of 500 patients (10.2 %). Only two clinical factors were significant: focal neurologic deficit (adjusted odds ratio (OR) 20.7; 95 % confidence interval (CI) 9.4-45.7) and age >55 (adjusted OR 3.08; CI 1.44-6.56). Area under the ROC curve for all three algorithms was 0.73-0.83. In proposed algorithm C, only patients with focal neurologic deficit (major risk factor) or ≥2 of the five minor risk factors (altered mental status, nausea/vomiting, known malignancy, coagulopathy, and age) would undergo CT imaging. This may reduce utilization by 34 % with only a small decrease in sensitivity (98 %). Our simple scoring algorithm utilizing multiple clinical risk factors could help to predict the non-trauma patients who will benefit from CT imaging, resulting in reduced radiation exposure without sacrificing sensitivity.