Study On The Value Of Apparent Diffusion Coefficient （ADC Value） And Relative Apparent Diffusion Coefficient （rADC Value） In Diagnosing Intracranial Space-occupying Lesions

Objective:In this study,the apparent diffusion coefficient（ADC value）and relative apparent diffusion coefficient（rADC value）in solid area,surrounding edema area and cystic necrosis area of intracranial space occupying lesions were analyzed to explore the application value of ADC value and rADC value in the differential diagnosis of intracranial space occupying lesions.Materials and Methods:The clinical data of 94 patients with intracranial space-occupying lesions who received craniotomy or biopsy from July 2019 to December2021 in the Neurosurgery Department of China-japan Friendship Hospital of Jilin University were selected.There were 25 cases of high-grade glioma（HGGs）,20 cases of low-grade glioma（LGGs）,10 cases of schwannoma,21 cases of meningioma,10 cases of metastatic tumor,7cases of brain abscess and 1 case of hemangioblastoma.ADC values of HGGs,LGGs,meningioma and schwannoma were measured in tumor body and peritumoral edema,and rADC values were calculated.The diagnostic efficiency of HGGs and LGGs was compared by comparing THE ADC value and rADC value of tumor area,and the correlation between the ADC value and rADC value of glioma grade and tumor area was analyzed.ADC values were measured and rADC values were calculated in the purulent cavity area or cystic necrosis area and peripheral edema area of brain abscess and cystic necrosis area and peripheral edema area.Result:1.The ADC Mean value and rADC value of HGGs were lower than those of LGGs,with significant statistical difference（P<0.001）.The sensitivity and specificity of ADC mean were 80.00% and 76.00%respectively.The sensitivity and specificity of rADC values were 80.00%and 80.00% respectively.The mean ADC value and rADC value were negatively correlated with glioma grade（r=-0.605 and-0.646,respectively）.However,the ADC mean value of HGGs and LGGs and rADC value of THE peritumoral edema area had no statistical significance（P>0.05）.The results showed that rADC value was more effective than ADC mean value in differentiating HGGs from LGGs.2.The ADC Mean value and rADC value of schwannoma were higher than those of meningioma,and the difference was statistically significant（P<0.001）.The sensitivity and specificity of ADC mean were80.00% and 90.50% respectively.The sensitivity and specificity of rADC values were 80.00% and 95.20% respectively.The results showed that rADC value was more effective than ADC mean value in differentiating schwannoma from meningioma.3.The ADC Mean and rADC values in the necrotic area of cystic brain tumor were higher than those in the abscess cavity,and the difference was statistically significant（P<0.001）.There was no statistical significance in ADC mean and rADC values of cystic necrosis area or edema area around abscess cavity of brain tumor and abscess（P>0.05）.Conclusion:1.The sensitivity and specificity of ADC mean value and rADC value in differentiating brain abscess and cystic necrotizing brain tumor were 100%.ADC mean and rADC values were most effective in differentiating brain abscess from cystic necrotizing brain tumor.2.ADC value has certain reference value for the prediction of glioma grade,and is negatively correlated with glioma grade.According to ROC analysis results,the sensitivity and specificity of rADC value for HGGs and LGGs were significantly higher than that of ADC mean value for HGGs and LGGs.3.When it is difficult to distinguish meningioma from vestibular schwannoma,ADC value and rADC value can be used as important parameters to distinguish the two.According to ROC analysis results,the sensitivity and specificity of rADC value in differentiating schwannoma from meningioma was higher than that of ADC mean value.4.At present,MR-DWI cannot replace the pathological results of biopsy or surgery.