MRI Evaluation Before The Radiation Treatment Following The Surgery On The Glioblastoma

Background and ObjectiveGlioma is the most popular primary tumor in skull.The occurrences of glioblastoma are 35%-61% of the intracranial tumors.77.5% of Gliomasare glioblastomas.The occurrences of glioblastoma are increasing year and year.The main therapy is removal with surgery.Due to the biological character of infiltrative growth of the tumors,it is difficult to remove completely the tumors with surgery.Furthermore,the tumors easily reoccur after the surgery.As a result,the auxiliary radiation treatment is generally employed after surgery.In order to precisely define the target region for radiation treatment after surgery,the position,morphology and size of the residual tumors,the MRI image of the glioblastoma after the surgery and before the radiation treatment is discussed in this research to provide direction to define the target region for the radiation treatment following the surgery.Materials and methodThe MRI images of patients of glioma after surgery and before radiation treatment in 106 cases are reviewed,of which the benign astrocytic gliomas in 36 cases are in the control group;the malicious gliomas in 70 cases are in the test group.Both are Supratentorial gliomas.All the cases after surgery are confirmed withpathology.One month before surgery and after surgery the tumors are subjected to plan MRI scan and enhancement scan.Within the boundary of 1cm to the peritumoral area,the peritumoral edema area is divided into the near peritumoral edema area and the far peritumoral edema area.The ADC is measured for the near peritumoral edema area and the far peritumoral edema area,respectively,and the correspondingrADC values are calculated.All the cases are trailed to the formation of softening lesion or reoccurrence of tumors.All the patients are let known and agree with the research.ResultThe features of MRI of the glioblastoma before radiation treatment and after surgery:(1)the occurrence of postoperative reactional enhancement is 52.9%(37/70).The occurrence is present as early as 18 hours after surgery and the most obvious during 6 days to 30 days after surgery.The tumors appear circle and the thin walls are obviously enhanced.The walls are smooth,regular,sharp and of uniform thickness.The minimum thickness is less than 1mm,and the maximum thickness is around3.5mm.Most of the thickness is not more than 3mm.Most of the circled walls are accompanied with the nodular enhancement.DWI has not the symptom of obvious dispersion.(2)the occurrence of residual tumors is 15.7%(11/70).The outline of lesion is not clear with blur boundary.The maximum thickness is around 5mm.the minimum thickness is 2mm.most of the thickness is not more than 3mm.the lesion appears the shape of garland,nodular or lump enhancement.There is the contrast to the enhanced tumors before surgery.DWI displays high signal,while ADC displays low signal.(3)The high occurrence of meninx enhancement near the surgery region is around 81.4%(57/70).The tumors display the enhancement of arc shape.The enhancement thickness is around 2--3mm with the maximum of around 4mm;(4)edema after surgery: there is a high occurrence of around 87.1%(61/70).FLAIR displays high signal.DWI is not restricted from dispersion.It is difficult to identify edema after surgery from peritumoral edema region before surgery.The rADC value(1.75+0.24)of the region near the benign glioma and the rADC value(1.87+0.22)of the far region have not significant statistical difference(P=0.13).The rADC value(1.62+0.39)of the near region of malign glioma is significantly lower than that(1.93+0.56)of the far region.P=0.00 is obtained.There exists the statistical significance.The rADC values for near region and the far region of benign glioma and malign glioma have not significant statistical difference(P>0.05);(5)hematocele or errhysis in the surgery region is around 35.7%(25/70).T1 WI displays high signal.ConclusionThe MRI images of glioblastoma after surgery display the complexity and diversity.However,each sequence of MRI has its own features and the value of identification which can provide comprehensive and detailed image information.Further direction is provided to define the region for radiation treatment.There exists the important clinical significance for the preparation of therapy protocol for further radiation treatment.