Evaluating The Relevance Of Corticospinal Tract Injury And Motor Function Recovery By Using Diffusion Imaging Before And After Mass Resection

[Objective] Brain tumors usually locate near the motor areas, even involve the motor areas. Especially the brain gliomas usually locate cortical area and white matter, and lead to damage of the function of neurons and white matter fibers. So it bring about clinical sings and symptoms. We demand to know the relationship of tumor and white matter, and the degree of tumor involving the matter. Research of this topic apply the technique of diffusion tensor imaging and diffusion tensor tractography to sought correlations between preoperative and postoperative DTI and clinical motor deficits in patients with space-occupying lesions involving the corticospinal tract (CST). DTI should be of great value in the microsurgical planning as well as estimation and reduction of potential postoperative neurological deficits for the cerebral tumors resection.[Materials and Methods] DTI and DTT were performed using Siemens Magnetom Avanto 1.5T and Trio Tim 3.0T imaging system. To that end,We sought correlations between preoperative and postoperative DTI and clinical motor deficits in patients with space-occupying lesions involving the corticospinal tract (CST).46 cases of brain tumors were come from Tianjin huanhu hospital January 2009 to 2010,all the patients with histologically confirmed. All the patients underwent routine MRI, contrast-enhanced MRI,DTI and DTT, analyzing the relationship between the changes of white matter fibres around the tumors and the side of limb muscle strength weakened. Fractional anisotropy(FA) values were measured in regions of CST were injured by tumors and contralateral normal CST. Comparing the differences of FA values between injured by tumors and contralateral normal CST using paired t-test; Comparing the differences between meningeoma,metastatic tumor,low grade astrocytoma and high grade astrocytoma (FA) were injured by tumors using ANOVA. Using the Spearman rank correlation analysis revealed, there was a significant correlation (rs=-0.848, P<0.001) between the CST injured degree and musle strength. Comparing the differences of motor deficits in patients with different tumors involving the corticospinal tract (CST),and comparing the differences of motor deficits in patients with tumors involving the different position of CST usingX2 test. The measurement results indicated with, x±s P<0.05 that the difference was statistically significant.[Results]1. FA changes of CST were injured by meningeon,metastatic tumor,low grade astrocytoma,high grade astrocytoma and contralateral normal CST FA values were 0.681±0.126,0.762±0.047; 0.303±0.101,0.624±0.025; 0.605±0.19,0.659±0.119; 0.528±0.236,0.682±0.112, by the paired t-test,were not found significant statistical difference of meningeoma and low grade astrocytoma of lesions side and normal side,P>0.05.There were found significant statistical difference of metastatic tumor and high grade astrocytoma of lesions side and normal side,P<0.05.2. Between meningeoma,metastatic tumor,low grade astrocytoma and high grade astrocytoma (FA) were injured by tumors using ANOVA,were found significant statistical difference, using ANOVA.3. Using the Spearman rank correlation analysis revealed, there was a significant correlation (rs=-0.848, P<0.001) between the CST injured degree and musle strength.4. The rate of muscle strength decline with space-occupying lesions involving the corticospinal tract were 50%(5/10),75%(3/4),70%(7/10),86.4%(19/22), were not found significant statistical difference (X2=4.816, P>0.05), byX2test.5.The relationship between the degree of CST injury and musle strength and the degree of muscle strength returned.Meningeoma lead to CST shift (8/10),but the structure was complete.50% patients had motor deficits, and the musle strength wasⅣ, and only lightly decline. We could observe the CST repositioning on FA map and DTT map after operative,at the same time the musle strength returned normal. Metastatic tumor not only lead to CST shift but also lead to CST break(3/4),75% patients had motor deficits,3 cases musle strength wereⅢ, and returnedⅣafter operative.1 case was not involved.10 cases were low grade astrocytoma,3 cases'CSTs were shifted and part of them were broken,6 cases'CSTs were slightly shifted,1 case was not involved.70%(7/10) patients had motor deficits,4 cases musle strength wereⅢ, and 2 cases were IV after operative,and 2 cases; returnedⅤafter operative.2 cases musle strength were IV,and returned V after operative.22 cases were high grade astrocytoma,6 cases'CSTs were shifted and part of them were broken,13 cases were shifted,3 cases were not involved. 86.4%(19/22) patients had motor deficits,1 case musle strength wasⅠ,and it returned to V after operative.2 cases musle strength wereⅡ,1 case returned toⅣ,1 case declined to 0.4 cases musle strength wereⅢbefore operative,1 case was stillⅢ1 case returned toⅣ, 1case declined toⅠ,1 case declined to V.11 cases musle strength wereⅣpreoperative.10 cases musle strength returned to V.1 case left lower limbs musle strength wereⅣ,1 case returned to V.3 cases musle strength were V preoperative and postoperative.[Conclusion]1. The meningeoma at the surface of brain,it can press the brain lead to it shift,but it can not destroy the brain.The positon of CST can recovery to normal and it can keep to integrity.So meningeoma injury the CST is gently,and the muscle strength is not low obviously.The muscles strength can recovery to normal afteroperation.2. Metastatic tumor,low grade astrocytoma,high grade astrocytoma take place in the brain.They can injury the CST immediatenessly.The degree of injury of CST concerned with distance of tumors and CST.The distance of tumors and CST was close the degree of injury of CST was severity.The degree of malignant was high which lead to the degree of injury of CST was severity.Which destroyed the integrity and directionality of CST.It was concerned with muscle strength and the degree of muscle strength recovery afteropetation.3. FA values was important parameter,which reflect the integrity and directionality of CST.Low FA values reflect the quantity of CST were reduce,which prompted the anisotropy of diffusion were low.It hinted that muscle strength was low and it recovery to normal was very difficulty postoperative.So it was very important to patients to treat at early stage of tumors.4.DTT can clearly and accurately show the relationship between the CST and brain tumor, it can provide message for operation.The degree of CST damage was closely related with the change and the recovery in motor function. The more serious damage in CST, the much lower score of limb muscle strength, but recovery in limb motor function was concerned with operation. In accordance with the relations of the CST damage degree and muscle strength can provide valuable prognostic information for postoperative treatment and rehabilitation.