Normal computed tomograms in acute head injury: correlation of intracranial pressure, ventricular size, and outcome

To assess the predictive value of a normal computed tomographic (CT) scan obtained shortly after head injury, we reviewed all cases of patients with acute closed injury seen at the North Carolina Baptist Hospital over a 42-month period for whom initial CT scanning and continuous intracranial pressure (ICP) monitoring had been done. Of 160 patients meeting those criteria, the initial CT scan was interpreted as normal in 17 patients, all of whom had a Glasgow coma scale score of 9 or less. Of those 17 patients, 7 had elevated ICP (higher than 25 mm Hg) and required mannitol. Six of the 7 had a major pulmonary injury. From the 27 CT scans of the 17 patients, we calculated an inverse cella media index and compared it to previously published standards in an attempt to delineate more quantitatively the "slit ventricles" often seen in cases of head injury. Two patients died of extracranial injuries; I had severe disability and 2 had moderate disability - all related to extracranial factors. The remaining 12 made good recoveries. From these findings, we conclude that a normal initial CT scan in patients with closed head injury and pulmonary injury does not preclude increased ICP (and thus should not preclude ICP monitoring) and that patients with closed head injury and a normal initial CT scan in the absence of associated extracranial injuries should make a good recovery.