The Prospective Study About The Relationship Between The State Of Perimesencephalic Cistern On Computed Tomography Scaning And The Outcome Of The Patients Suffering Acute Craniocerebral Injury

Lately,more and more authors attached importance to the CT scanning features ,especially the status of perimesencephalic cistern as a prognostic parameter for patients with acute craniocerebral injury. Most authors described the status of perimesencephalic cistern as open,compressed or absent cisterns. However, no one has quantified the status of perimesencephalic cistern and described the correlation between the quantified status of perimesencephalic cistern and outcome.This study try to explore the relationship between the state of perimesencephalic cistern on computed tomography scaning,the degree of the deformation of midbrain and the outcome of the patients suffering acute craniocerebral injury. A prospective study was carried out on 132 successively hospitalized cases of acute craniocerebral injury. Initial CT scanning was performed in all cases 20 minutes to 12 hours after trauma. The CT scan features including the states of perimesencephalic cisterns, the deformation of midbrain and the ratio of occipitofrontal diameter and transverse diameter of the midbrain of 132 cases were measured .132 cases were divided into 6 groups according the width of perimesencephalic cistern: absent cisterns group, narrower than 0.5mm group, 0.5-lmm group, 1-2mm group, 2-3mm group and wider than 3mm group. Meanwhile, 132 patients also were divided into 2 groups: deformed midbrain group and undeformed midbrain group and into 2 groups according the ratio of occipitofrontal diameter and transverse diameter of the midbrain: abnormal ratio group (<0.9 or > 1.1)and normal group (0.9-1.1) respectively The patients in each group were dichotomized into unfavorable (dead, vegetative status, severe disability) and favorable outcome (good recovery/moderate disability) respect to the GOS at 3 months and the outcomes of patients in each feature were examined using chi-square test.Results:The rates of favorable outcome (moderate disability/good recovery) of the patients in absent cisterns group, narrower than 0.5mm group,0.5-lmm group,1-2mm group,2-3mm group and wider than 3mm group were 37.04%, 52.38%, 58.82%, 85.00%, 77.27% and 92.00% respectively. The mortality rate or the possibility of living vegetatively of the patients with perimesencephalic cistern narrower than 1mm(P<0.05) ,especially narrower than 0.5mm(P<0.005) was very high . Deformation of midbrain also significantly influence outcomes of those patients. In the deformation group, 26 patients recovered favorably (48.15%) and 28 unfavorably (51.85%); however, in the undeformation group, 62 patients recovered favorably(79.49%) and only 16 unfavorably (20.51%) (P<0.005). The rate of unfavorable recovery increased to 42.67% when the ratio of occipitofrontal diameter and transverse diameter of the midbrain was more than 1.1 or less than 0.9 and only 21.05% when the ratio between 0.9 to 1.1. (P<0.01). Conclusion: The state of compressed perimesencephalic cistern(<1mm) and the deformation of midbrain would significantly enhance the mortality rate or the possibility of living vegetatively of the patients with acute craniocerebral injury.