Indications for computed tomography in patients with minor head injury

Computed tomography (CT) is widely used as a screening test in patients with minor head injury, although the results are often normal. We performed a study to develop and validate a set of clinical criteria that could be used to identify patients with minor head injury who do not need to undergo CT.

In the first phase of the study, we recorded clinical findings in 520 consecutive patients with minor head injury who had a normal score on the Glasgow Coma Scale and normal findings on a brief neurologic examination; the patients then underwent CT. Using recursive partitioning, we derived a set of criteria to identify all patients who had abnormalities on CT scanning. In the second phase, the sensitivity and specificity of the criteria for predicting a positive scan were evaluated in a group of 909 patients.

Of the 520 patients in the first phase, 36 (6.9 percent) had positive scans. All patients with positive CT scans had one or more of seven findings: headache, vomiting, an age over 60 years, drug or alcohol intoxication, deficits in short-term memory, physical evidence of trauma above the clavicles, and seizure. Among the 909 patients in the second phase, 57 (6.3 percent) had positive scans. In this group of patients, the sensitivity of the seven findings combined was 100 percent (95 percent confidence interval, 95 to 100 percent). All patients with positive CT scans had at least one of the findings.

For the evaluation of patients with minor head injury, the use of CT can be safely limited to those who have certain clinical findings.