OBJECTIVETo explore prospectively the relationship between the state of perimesencephalic cistern and the degree of deformation of the midbrain on CT scanning and the outcome of the patients with acute craniocerebral injury.

METHODSThe CT scan features including the states of perimesencephalic cisterns, the deformations of the midbrain and the ratios of the occipitofrontal diameter and the transverse diameter of the midbrain of 132 cases were measured. The GOS of the patients 3 months after trauma were regarded as outcome.

RESULTSThe rate of unfavorable outcome (dead, vegetative status, severe disability) was significantly correlated with perimesencephalic cistern narrower than 1 mm (P<0.05), especially narrower than 0.5 mm (P<0.005), deformed midbrain (P<0.005) or abnormal ratio (<0.9 or >1.1) of the occipitofrontal diameter and transverse diameter of the midbrain (P<0.01). But the patient's perimesencephalic cistern wider than 1mm and the patients without deformed midbrain got favorable outcome (moderate disability/good recovery).

CONCLUSIONSThe state of the compressed perimesencephalic cistern (<1 mm) and the deformation of the midbrain may significantly indicate unfavorable outcome of the patients with acute craniocerebral injury.