Objective To analyse the effect of Naoshuning on brain edema through observing the dynamic changes of magnetic resonance imaging（MRI） in rats with brain contusion and laceration.Methods All 114 male SD rats were randomly divided into Naoshuning group

model group and sham-operation group. The rat model of brain contusion and laceration was established by free-falling impact according to Feeney’s method.After the operation the dynamic changes of MRI signal intensity（SI） and volume in T

2

WI focus were observed consecutively

and the brain water content was determined by using dry-wet method.Results There were changes observed in increased SI of T

2

in the cerebral hemisphere with operation.SI got the highest level and volume on the first day and then decreased gradually and reached the lowest level on the seventh day

which showed a parallel course with brain water content.In Naoshuning group SI in T

2

WI focus

edema volume and brain water content were significantly lower than those in the model group at all time points（P

<

0.05）.The absorption rate of edema in Naoshuning group was significantly higher than that in the model group（P

<

0.005） seven days after the operation. Conclusion The non-invasive MRI examination can be used to analyse quantitatively the degree of brain trauma and edema in rats after the treatment with Naoshuning

which is reliable for review the curative effect.Naoshuning can improve the absorption of edema after brain contusion and laceration.