Dilatation of the temporal horn in subarachnoid haemorrhage.

CT studies of 50 patients with spontaneous subarachnoid haemorrhage (SAH) and 100 randomly selected patients were reviewed with regard to the size of the frontal and temporal horns of the lateral ventricles. The temporal horn was classified into four grades, based on the size of its posterior portion at the level of the midbrain. The horn was clearly visible in 66% of patients with SAH, but in only 2% of controls. In the SAH group, the temporal horn tended to dilate sooner than the frontal horn after haemorrhage and could be seen clearly in a larger proportion of patients. Thus, assessment of the size of the temporal horn appears to be a simple and sensitive method for assessing ventricular dilatation. In addition, dilatation of the temporal horn may prove to be an important indirect sign suggesting SAH in patients in whom no high density clot is seen on CT.