The Clinical Application Of Diffusion Tensor Imaging In The Prognostic Assessment Of The Motor Areas Of Cerebral Cortex

Objective: This research applied the technology of magnetic resonance diffusiontensor imaging（DTI）in the patients with tumors in cortical motor areas, observed thechanges of fractional anisotropy（FA）in corticospinal tract（CST）, evaluated theimpairment and repair of cortical spinal tract, investigated pathophysiological mechanismsof neurologic injury and repair in the view of molecular image, and aimed to provide atheoretical basis for the design of individualized surgical treatment and prognosticevaluation for the patients with cerebral cortex motor area.Methods: Twenty cases of cerebral cortex motor area tumors were included in thisstudy. Inclusive criteria:①Tumor located in the cerebral cortex motor area.②Initial onset,no history of chemotherapy or radiation therapy.③stable vital signs, alert, cooperated inthe DTI scans.④No severe heart, lung, liver, renal dysfunction and other serious systemicdiseases.⑤Strictly complied with the orders to complete follow-up.⑥Approval of theconsent of the patient and/or their families. The group consisted of20patients,14malesand7females (age:11～69, average:45.80±14.31). All patients underwent surgicaltreatment. According to the pathological findings, patients were divided into2groups：intra-axial tumor group(glioma12cases) and extra-axial tumor group (meningioma7cases and metastatic tumors1case). All the patients underwent conventional MRI and DTIexamination (TE/TR:112minimum/10000ms, matrix:128×128， FOV:240mm,thickness:4.0mm, spaceing:0.5mm,b value:1000s/mm2,) using GE signa exiteimaging system. The data were used to generate fractional anisotropy maps by the softwareof Dtv.Ⅱ.R2. The FA value were measured in the region of compressed CST andcorresponding contralateral normal regions, directionally encoded color maps and3Dtractography of bilateral CST of all patients were created.The Brunnstrom scale wereemployed for assessment of the functional status at the time of pre-opertaion, the seventhday after surgery, sixth month after surgery. FA values of bilateral CST were measured.The configurations of CST were showed using DTI. SPSS13.0were used to assess therelationship between FA value and CST injury, Brunnstrom scale and recovery. Results: The FA value in the region of compressed CST was significant lower thanthat in normal hemisphere. FA images and3D DTI can display corticospinal tract clearly.DTI shows that the CST was compression, displacement, translocation, and break. Fourgrades could be defined according to the DTI: integral CST with no compression anddisplacement (Grade1), integral CST with compression and displacement (Grade2),partial discontinuity of CST(Grade3), completely discontinuity of CST(Grade4). At thethree time points, the reduction of ipsilateral CST FA values were negatively correlatedwith Brunnstrom score and ipsilateral CST injury was negatively correlated withcontralateral limb muscle strength. In this research, we find that:①The7th postoperativeday CST injury level and Brunnstrom score decreased significantly compared with thepreoperative.②CST injury level and Brunnstrom score after6months improvedsignificantly compared to7days after the surgery, even better than preoperative.③CSTdamage level of the intra-axial lesions were more higher than the level in the extra thelesions, and postoperative recovery is poorer.④The recovery of limb muscle strengthdepends on the repair of the CST.Conclusion: The FA value, a parameter of the diffusion tensor imaging, may thequantitatively reflect the damage of the corticospinal tract in the patients with cerebralmotor area tumors. DTI can vividly display the damage of the corticospinal tract in thepatients with the cerebral cortex motor area tumors.The integration and reconstructiontechniques can further show the tridimensional relationship between tumor and CST. DTIand DTT analysis of CST damage were of great value in the design of surgical plan and theassessment of neurological impairment and prognosis. Intra-axial tumor group, comparedwith extra-axial tumor group, showed higher CST injury level and poorer limb functionrecovery. Recovery of neurological function may depend on the restoration of the CST.