| part1Rearch of the relation between the MR imaging characteristicand the grade of pathologyof Brainstem GliomasBackground and ObjectiveBrainstem glioma is the most common tumor in brain lesions, which accounts for more than75%. The brain stem is the central life, which consists of all kinds of complicated nerve nuclear group and fiber bundle.The risk ofbrainstem surgical is greatly.while glioma shows infiltrative growth and its lesions boundaries are difficult to be identified,that is undoubtedly increase the difficuty of surgery.Due to the above reasons,the operation of brainstem glioma is one of the most challenging surgery in the neurosurgery field. MRI is consideredto the better imaging examination for describe glioma growth characteristics, especially enhance MRI can more perfect understanding the growth of gliomas characteristics. At present, the research about MRI imaging supratentorial gliomas has been more and more mature. Different from the supratentorial gliomas, brainstem glioma MRIperformance has the characteristics of its own because of the complex anatomy characteristics. Perfectlygrasping these features is better for us anticipatingpathological level before, making operation strategyand improve prognosis. Limited to the low overall incidence of brainstem glioma andthe greatly risk of surgical, few units can carry out the brainstem operationespecially brainstem gliomas operation in the domestic. So, the literature about big cases of brainstem glioma MRI imaging findings is less, the experience available for reference is so little. We review a large number of brainstem glioma MRI characteristics in order to summarize different pathological grading brainstem gliomas’MRI feature^anticipate pathological gradingin the preoperative and make operation strategy.Methods94cases of patients with brainstem gliomas,who has accepted surgery treatment in the NanFang Hospital on January1,2004to December1,2010,are divided into high-grade gliomas (WHO Ⅲ-Ⅳ) group and low-grade glioma group (WHO Ⅰ-Ⅱ).MRI characteristics of brainstem gliomas were retrospectively analyzed, using the PACS image system.Compare the difference between the two groupson preoperative enhance MRI tumor size, origin place, growth type, enhance, cystic degeneration,the necrosis, cross midline growth, package basal artery, T1and T2sequence signal. Use SPSS16.0application package do a chi-square test, P<0.05as statistically significant.ResultsThere was significant difference (P<0.05) of the cystic degeneration the necrosis、cross midline growth、package basal arterybetween high-grade gliomas group and low-grade gliomas group. There was no significant difference (P>0.05) of the origin place、growth type、enhance、tumor size、T1and T2sequence signalbetween high-grade gliomas group and low-grade gliomas group.Conclusion1、MRI imaging characteristics of the brainstem glioma performance is diverse.To a certain degree,we can judge the malignant glioma degree preoperative through the cystic degeneration、the necrosis、cross midline growth and package basal artery, and guide the operation plan and make the next step treatment.2、Tumor signal on MRI, enhance efficiency, the origin of position and brainstem glioma degree of malignancy have no reference to tumor pathology grade. Preoperativewe cannot use these images features anticipate degree malignant. But in some extent, they could help us understand tumour texture and other biological characteristics, which can help doctors estimate operation difficulty, improve operation effect.3、Brainstem glioma operation indications including focal endogenous glioma、 exogenous glioma、tectum glioma. Operation effect of the three kinds of brainstem glioma is good, the prognosis is satisfied. Wethink total resection of the tumor as far as possible is the first choice for those patients. Operation effect of diffuse brainstem glioma is poor, prognosis is poor,we do not suggest directly surgery as the first choose.4、The diameter of focal brainstem glioma has nothing to do with pathologic grade. There are still a big part of low-grade gliomas in the tumor,whosediameter more than2cm.Tumor size is not sole factor to judge whether it can be surgery, and effect the curative effect of operation.With the help of skilled microsurgical technology、the new equipment such as laser knife, a lot of gliomas, whichwas defined as diffuse type in the past time, can also has a chance of a surgery and improve their life cycle through "sculpture type" resection. More of the large brainstem glioma can also have the opportunity through the surgery made pretty good curative effect.5、The volume of exogenous brainstem glioma usually is very largest. The diameter commonly exceed2cm.They usually grow surpass the brainstem back side, even enter intofourth ventricle. The risk of surgery in this type gliomausually is small. Most of them can get a better outcome through resecting the tumor along the exogenous section begins.6、Different from the other gliomas, mosttectum gliomas are low-grade gliomas,which have a special biological characteristics of their own. Tumor diameter is concerned withglioma grade. Most of themcan get good prognosis through actively surgery. Prognosis of tectum gliomais is one of the best prognosis of all brainstem gliomas.part2Application of MR diffusion tensor imaging in preoperation and postoperation patients of brainstem lesionBackground and ObjectiveBrainstem lesions accounts for approximately1.4%-2.4% of all brian tumorand more than10%-20% of childhood central nervous system tumors. Treatment of brainstem lesion include surgery、radiation therapy and chemotherapy. The brain stem is the central life, which consists of all kinds of complicated nerve nuclear group and fiber bundle.The risk of brainstem surgical is greatly, So the operation of brainstem glioma is one of the most challenging surgery in the neurosurgery field. Intraoperative to protecting the vital fiber which surrounding lesions is the key to the success of the operation. Conventional MRI techniques can offer the information about lesion location、size and so on, which could help to anticipate pathological grading in the preoperative and make operation strategy. But the MRIcan’t distinguish the fiber bundles around brainstemlesion,This obviously can’t satisfy the neurosurgeon who want to protect important fiber surrounding the lesions.Diffusion tensor imaging (DTI) is a new non-invasive imaging technology in recent years, which is based on conventional MRI techniques and diffusion-weighted imaging (DWI) techniques and can show white matter fiber bundles in vivo.More and more applications of diffusion tensor imaging (DTI) and diffusion tensor tractography (DTT) in the field of neurosurgery have been used, especially in the preoperative diagnosis of supratentorial tumors, preoperative evaluation of supratentorialtumor characteristics, operation guide for the surgeon to remove the tumor aspossible and to protect thesurrounding vital nerve fiber bundle, and postoperative evaluation of effects after tumorresection. DTIimage is easy to distortion Because of the complex brainstem and brainstem periphery anatomical structure and brainstem lesions in the posterior fossa.Because above reason, a little applications of diffusion tensor imaging (DTI) and diffusion tensor tractography (DTT) in the field of brainstem lesion have been usedin the domestic. So, the experience available for reference is so little. We review20brainstem lesionDTI characteristics in order to summarize brainstem lesionDTI feature-. anticipate pathological grading in the preoperative and make operation strategy.Methodspatients and Control SubjectsThe study was approved by the local Institutional Review Board at NanFang Hospital. Twenthpatientswith a brainstem lesion as experimental groupwere included in the study. Another10healthy adult as control group (5girls,5boys;18-38years of age) Data Acquisition and AnalysisAcquisition.All patientswere scanned on a3.TMR scanner (GE signa Excite) with an eight-channel head coil utilizing SENSE parallel imaging technique. DTI was acquired using a single shot spin-echo echo-planar imaging; TR12,000ms, TE75.6ms, slice thickness3mm, gap0mm.25diffusion directions at b=1000s/mm2were acquired in addition to b=0images. Acquisition time was about6min.44slices were taken for whole brain coverage from vertex to foramen magnum. All data were transferred to a workstation for analysis with Functool software supplied by GE signa Excite. Color coded Fractional Anisotropy (FA) and apparent diffusion coefficient (ADC) maps were calculated. The maps were then stored and reviewed by using the hospital PACS system.Analyses.ADC and FA values of the brainstem lesionand healthy adult were measured at5different axial levels of the brain stem:cerebral peduncles, rostral pons, mid pons, caudal pons, and rostral medulla. To ensure consistency and consensus, all the regions were outlined by the same technician, and2board-certified neuroradiologist subsequently confirmed them. Areas with necrosis and cystic degenerationwere excluded to the extent possible, patterns of fiber alteration based on morphological appearance were classified in four groups similar to Lazar’s technique as follows:Group I:"normal";Group Ⅱ:"deviated" if the tract was in abnormal location and/or direction due to mass effect of the lesion; Group III:"deformed" if there was a partial defect or interruption in parts of tractwhile rest of itwas identifiable on directional color maps and DTT; Group IV:"interrupted" if the tractwas discontinuous or defective completely on FA color maps and DTT.ADC values and FA values values were measured and analyzed in regions of solid tumor, surrounding edema, adjacent normal white matter in10cases of low-grade gliomas and5cases of high-grade gliomas.10healthy normal persons were examined using DTI, and white matter fiber tracts of the three-dimensional were reconstructed.2D ROI set is seed, ROI were set at the base of the pons and internal capsule limb, and then"Tracking Multiple a ROI of nerve fibers"generated three-dimensional tracer images of bilateral CST、ML and so on.Evaluation of neurological deficits and follow-up. Neurological examinations and DTIs were repeated after surgery within a week and after3months.Neurological findings werecompared with qualitative assessment of DTT before and aftersurgery.Neurological information for motor, sensory, and cranial nerve findings were complete in all20patients with brainstem lesions. The neurological evaluation was performed by a investigator blinded to the DTI findings.The neurological deficits were classified into4categories:motor, sensory, cranial nerve, and ataxia. The severity of deficitwithin each category (except sensory) was also graded as follows: absent if no deficit was present; mild if neurologic deficit resulted in no loss of function of the limb or, in the case of cranial nerves,50%loss of function;moderate if neurologic deficit resulted in loss of function that restricted activity or, in the case of cranial nerves,50%loss of function; and severe if there was marked loss of function prohibiting activity and complete paralysis in the case of cranial nerves. Sensory deficits were graded as absent if not present, mild if noted by the examiner only, moderate if the patient reported with no loss of function, and severe if loss of sensation affected function of the limb as well.Statisticalanalysis.All tests were performed by using SPSS16.0. A P value of0.05was considered statistically significant.Results1、The DTI signal of grey and white matter is different.Corticopontine, corticospinal, inferior and superior cerebellopeduncular, transverse, medial lemniscal could be display in the DTI. In the FAimaging,those fiber present equal or low signal. And that nerve nuclei present equal or high signal. In the ADC imaging,fiber present equal or high signal,the nerve nuclei present equal or low signal.The color-coding was assigned as red transverse, green anterior-posterior, and blue cranio-caudal directions.There was no significant difference (P>0.05) of the FA and ADC values of corticospinalis tractus、medial lemniscal、transverse、inferior and superior cerebellopeduncular between rostral pons, mid pons, caudal pons in the normal control group.2、Twenty patients (12male and8female) with an average ageof25.25years (range,4-55yr) with primary brainstem masses including three cavernomas, fifteen glial tumors, two hemangioblastomawere included in the study. Fifteen gliomas patients including ten brainstem low-grade gliomas and five high-grade gliomas.3、ADC values of corticospinalis tractus、medial lemniscal、transverse、inferior and cerebellopeduncular is higher in brainstem lesion than normal contral. There was significant difference (P<0.05) of the ADC values of corticospinalis tractus、medial lemniscal、transverse、cerebellopeduncular between patients group and control group.FA values of corticospinalis tractus、medial lemniscal、 transverse、 cerebellopeduncular is lower in brainstem lesion than normal contral. There was significant difference (P<0.05) of the FA values of corticospinalis tractus、medial lemniscal、transverse、inferior and superior cerebellopeduncular between patients group and control group.4、In benign and malignant tumors, displacement can occur in peritumoral white matter fiber tracts; White matter fiber tracts in tumor edema mainly showed edema infiltration and destruction, Edema and infiltration occur mainly in benign, low malignant brain tumor area. The destruction of white matter fiber tracts inmalignant tumors mainly related to peritumoral white matter fiber tracts and the extent of the damage Was proportional to the degree of malignancy of tumors.5、The states of fiber tracts were damaged greatly in the periphery of high-grade gliomas than low grade (P<0.05). Further, the states of fiber tracts were destroyed heavily in the periphery of gliomas that had higher expression of VEGF or Ki-67(P<0.05). But there were poor correlation (P>0.05) between MMP-9or CD44expression and the state of fiber tracts adjacent to gliomas.6、ADC values is higher in tumor area than in peritumoral edema area both for low-grade gliomas and high grade gliomas. There was significant difference(P<0.05) of the ADC values between tumor area, peritumoral edema area and the adjacent normal white matter. There was not significant.difference (P>0.05) of the ADC between real tumor area and peritumoral edema area for low-grade gliomas. The ADC value of solid tumor for high grade gliomas was higher than that of low-grade glioma, and there was significant difference statistically (P<0.05).The FA values showed no significant difference (P>0.05) between solid tumor area and peritumoral edema, but there was significant difference (P<0.05) between solid tumor and the adjacent white matter and eontralateral white matter for both low and high grade gliomas. There were significant differences between (P<0.05) among solid tumor regions of low and high grade gliomas, tumor edema, adjacent white matter. The FA values of solid area of low-grade gliomaslowerthan the high-level tumor parenchyma of FA values, and therewere significant differences between the two of them (P<0.05).7、There are18cases of motor dysfunction in20cases of patients with brainstem lesion, including10cases of mild,7cases of moderate and1cases of severe. The degree of motor dysfunction in connection with the value of△FA of CST (r=0.794,P<0.05). There are14cases of sensory dysfunction in20cases of patients with brainstem lesion, including10cases of mild,4cases of moderate. The degree of sensory dysfunction in connection with the value of AFA of ML (r=0.918,P<0.05)8、Depending on the relation between brainstem lesion and the surrounding fiber bundles in DTI, Growth type of pons lesion are divided into six categories.Q type:in the cross-sectional of DTI, the brainstem lesion originated in the backsides of brainstem.The CST、ML and TP are often displace in the front of the lesion. Because of the blocking effect of bilateral CST、ML and TP,the lesion usually grow surpass the brainstem back side, even enter intofourth ventricle.Most of the tumors are benign lesion,and the prognosis are satisfied.Stype(S1and S2):in the cross-sectional of DTI, the brainstem lesion is located in the front of ML and behind of CST or originated in pedunculus Cerebellaris Medius. S1type:The ML is often displace in the behind of the lesion. Because of the blocking effect of bilateral CST and ML, the lesion usually grow surpass the pedunculus Cerebellaris Medius, even enter intothe lateral of brainstem. Most of the tumors also are benign lesion,and the prognosis are satisfied.S2type:Most of the tumors also are malignancy lesion, the blocking effect of bilateral CST、ML and TP are so slight that the volumn of tumor is often large.The CST、ML are often infiltrated even destroyed. The lesion usually growcross midline of brainstem. The risk of surgery is great and the prognosis is not satisfying.T type:in the cross-sectional of DTI, the brainstem lesion is located in the front of CST. Most of the tumors also are benign lesion.Because of the blocking effect of bilateral CST and TP are so strong that the lesion usually grow intoprepontine cistern. The CST、ML are often displace in the behind of tumors. The risk of surgery is small and the prognosis is satisfied.Conclusion1、There was significant difference (P<0.05) of the FA and ADC values of corticospinalis tractus、medial lemniscal in the cerebral peduncles、rostral pons、 mid pons、caudal pons、rostral medulla. The value of FA of corticospinalis tractus in the cerebral peduncles is the most greatest than another lays. There was no significant difference (p>0.05) of the FA and ADC values of corticospinalis tractus、medial lemniscal、transverse、inferior and cerebellopeduncular between rostral pons, mid pons, caudal pons in the normal control group.The biggest value of FA of fiber is corticospinalis tractus, following medial lemniscal、 transverse、inferior and cerebellopeduncular2、DTT combine with MRI contribute to the diagnosis and differential diagnosis of brainstem lesions. Through determining the FA, ADC values of tumor surrounding in different parts, We can judge he boundary between the tumor essence area and normal tissue. So, DTI can provide the radiographic basis for total resection of the tumor safety.3、There is a linear relation between various fiber AFA and the degree of nerve function loss.4、The benign lesion such as cavernomas and hemangioblastomaoften push the surrounding fibers away, accompanying with infiltration.While, the malignancy lesion usually destroythe fibers.5、The states of fiber tracts surrounding the brainstem glioma is determined by glioma invasiveness,not by its proliferative.6、Depending on the relation between brainstem lesion and the surrounding fiber bundles in DTI, Growth type of pons lesion are divided into six categories. Q type:in the cross-sectional of DTI, the brainstem lesion originated in the back sides of brainstem. The CST、ML and TP are often displace in the front of the lesion. Because of the blocking effect of bilateral CST、ML and TP, the lesion usually grow surpass the brainstem back side, even enter intofourth ventricle. Most of the tumors are benign lesion,and the prognosis are satisfied. Stype(S1and S2):in the cross-sectional of DTI, the brainstem lesion is located in the front of ML and behind of CST or originated in pedunculus Cerebellaris Medius. S1type:The ML is often displace in the behind of the lesion. Because of the blocking effect of bilateral CST and ML, the lesion usually grow surpass the pedunculus Cerebellaris Medius, even enter intothe lateral of brainstem. Most of the tumors also are benign lesion,and the prognosis are satisfied. S2type:Most of the tumors also are malignancy lesion, the blocking effect of bilateral CST ML and TP are so slight that the volumn of tumor is often large. The CST、ML are often infiltrated even destroyed. The lesion usually growcross midline of brainstem. The risk of surgery is great and the prognosis is not satisfying. T type: in the cross-sectional of DTI, the brainstem lesion is located in the front of CST Most of the tumors also are benign lesion.Because of the blocking effect of bilateral CST and TP are so strong that the lesion usually grow intoprepontine cistern. The CST、ML are often displace in the behind of tumors. The risk of surgery is small and the prognosis is satisfied. |
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