Usefullness Of MR Diffusion Weighted Imaging In Evaluation Of Peritumoral Edema Of Brain Tumor

【Objective】Peritumoral edema is the common concomitantsymptom of brain tumor, frequently in gliomas and metastases. Theroutine magnetic resonance imagings which are well knowed can onlyshow the signal of the gross,appearance of the mass. MR Diffusionweighted imaging, DWI which depended on the movement of watermolecular can not only show the microcosmic massage but also analysisthe movement of the water molecular by using apparent diffusioncoefficient, ADC. DWI using in solid part of tumor before, but it is usedin evaluateing peritumoral edema this time, analysis the ADC characterof different brain tumors and different grades gliomas, study the value ofDWI in peritumoral edema.【Material and Methods】60 cases of brain tumors including 44gliomas and 16 metastases. All the cases were provedpathologyicallyroved clinically and were performed by precontrast MRIscan (including conventional sagittal,coronal T1-weighted images and axial T2-weighted images,DWI images) and postcontrast MRI scan(including sagittal, axial, coronal T1-weighted images). The solid partsof tumors are enhanced, which are isointensity or hypointensity inT1-weighted images and changed in T2-weighted images. Theperitumoral signal abnormality was divided into two regions to allowinvestigation of whether ADC varies with distance from the enhancingportion of the tumor. The region which is close 1cm called immediatetumomal edema, far than 1cm called distant peritumoral edema.Measured in immediate,distant peritumoral edema and contralateralcorresponding white matter. We measured 3-5 region of interest ROIS inevery region, calculated the mean of the region. We calculated the ratiosto the contralateral corresponding ROI of peritumoral edema and whitematter surrounding the edema.【Results】1. The figure and images of peritumoral edema(1) The figure and images of peritumoral edema in low-gradegliomas: Peritumoral edema of low-grade glioma is slight, it is ringedema surrounding the mass, the figure is regular, the infiltration tosurrounding white matter is not evident. The region shows slightly lowsignal on T1WI; slightly high signal on T2WI; high signal on FLAIR; slightly low signal on DWI; slightly high signal on ADC, and higher thancontralateral corresponding white matter; no enhanced postcontrast MRI,shows slightly low signal.(2) The figure and images of peritumoral edema in high-gradegliomas: Peritumoral edema of high-grade glioma is evident, it is largepatchy edema surrounding the mass, the figure is irregular, theinfiltration to surrounding white matter is evident, but usually restrictedby cortex and ventricles of brain. The region shows slightly low signal onT1WI; slightly high signal on T2WI; high signal on FLAIR; slightly lowsignal on DWI; slightly high signal on ADC, and higher thancontralateral corresponding white matter; no enhanced postcontrast MRI,shows slightly low signal.(3) The figure and images of peritumoral edema in single metastases:Peritumoral edema of single metastases is evident, it is lobulated edemasurrounding the mass, the figure is irregular, the infiltration tosurrounding white matter is evident,. The region shows slightly lowsignal on T1WI; slightly high signal on T2WI; high signal on FLAIR;slightly low signal on DWI; slightly high signal on ADC, and higherthan contralateral corresponding white matter; no enhanced postcontrastMRI. 2. DatesThe mean rADC of immediate peritumoral edema in low-gradegliomas is 2.1067±0.2474; the mean rADC of immediate peritumoraledema in high-grade gliomas is 1.8889±0.2918; distant peritumoraledema is 2.1449±0.2790; the mean rADC of immediate peritumoraledema in single metastases is 2.1442±0.2636; distant peritumoraledema is 1.8948±0.2168. The rADC of immediate and distantperitumoral edema in high-grade gliomas used two single specimen t-test,showed significant difference between them (t=2.974, P=0.005),immediate is lower than distant. The rADC of immediate and distantperitumoral edema in single metastases used two single specimen t-test,showed significant difference between them (t=2.923, P=0.007),immediate is higher than distant. The rADC of immediate peritumoraledema in low-grade gliomas,high-grade gliomas and single metastasesused the AVOVA indicate significant difference (F=5.355,P=0.007); the rADC of low-grade gliomas and high-grade gliomasshows significant difference (P=0.009), the rADC of singlemetastases and high-grade gliomas shows significant difference(P=0.005), the rADC of low-grade gliomas and single metastasesshows no significant difference (P=0.672), the the rADC of high-grade gliomas is lower than the other two. The above all used SPSS11.00 For Windows【Conclusion】1. Using DW I, the rADC of immediate peritumoral edema washelpful in differentiating high-grade glioma from metastasis. The rADCof immediate peritumoral edema of high-grade glioma is lower than thatof single metastases, the rADC of distant peritumoral edema shows nosignificant difference between high-grade glioma and metastasis.2. The rADC of immediate peritumoral edema is lower than that ofdistant edema in high-grade glioma, which is contrary to metastasis.3. The rADC of immediate peritumoral edema was helpful in gradingglioma. The rADC of immediate peritumoral edema is lower than that ofdistant edema in high-grade glioma, which is contrary to low-gradeglioma. The rADC of immediate peritumoral edema in high-grade gliomais lower than that in low-grade glioma.