The Role Of Diffusion Weighted Imaging In Differential Diagnosis Of Intracranial Tumors

Part I:The Role of Diffusion Weighted Imaging in Differential Diagnosis of Subtypes of MeningiomaObjective:To evaluate the role of diffussion weighted imaging(DWI)and Apparent diffusion coefficient (ADC) in differential diagnosis.of benign and malignant meningioma,and the role of DWI and ADC in differential diagnosis of different subtypes of meningioma.Materials and methods:We retrospectively analyzed the DW MR images (b-value 1000 s/mm2) of 141 cases of meningioma confirmed by surgery an pathology. We divided these cases into two groups,benign and malignant.The two group's ADC and rADC (ADC ratio) were compared,and the optimal cutoff for the ADC and rADC to differentiate between these groups was determined by using receiver operating characteristic(ROC) analysis.Indeed we divided these cases into several groups by their pathological subtype, and compare the ADC and rADC of these groups.Results:Among the 141 cases,67 were fibrous meningioma;51 were epithelial meningioma;9 were angiomatous meningioma;7 were Atypical meningioma;7 were anaplastic meningioma. The mean rADC of malignant meningiomas was significantly lower compared with benign meningiomas(P<0.01).ROC analysis showed that rADC thresholds of 0.84 had the best accuracy;the sensitivity and specificity were 78.6% and 81,4% respectively.The mean rADC of angiomatous meningiomas was significantly higher than any other subtypes(P<0.01).The mean rADC of anaplastic meningiomas was significantly lower than fibrous meningiomas,epithelial meningioma and angiomatous meningioma(P<0.01).There was no significant difference among fibrous meningioma,epithelial meningioma or atypical meningioma.The mean rADC of peritumoral brain edema of angiomatous meningioma was significantly higher than fibrous meningioma(p<0.05).Conclusion:ADC may provide important imformation about the pathological subtypes of meningioma and can improve the diagnostic accuracy of subtypes of meningioma.Part II:The Role of Diffusion Weighted Imaging in Differential Diagnosis of Different Grading of Glioma.Objective:To evaluate the role of diffussion weighted imaging(DWI)and Apparent diffusion coefficient(ADC) in differential diagnosis of different grade glioma. Materials and methods:We retrospectively analyzed the DW MR images(b-value 1000 s/mm2)of 124 cases of glioma(I-IV),each one had been confirmed by surgery an pathology. We divided these cases into two groups,benign and malignant.The two groups' rADC (ADC ratio)and rADCmin(minmum ADC ratio) were compared,and the optimal cutoff for the rADC and rADCmin to differentiate between the groups was determined by using receiver operating characteristic(ROC) analysis.Results:Among the 124 cases,7 were WHO I (pilocytic astrocytoma);43 were WHOII(Oligoastrocytoma);20 were WHOâ…¢(anaplastic astrocytoma);54 were WHOIV(gioblastoma).The mean rADC and rADCmin of high grade glioma was significantly lower compared with low grade glioma (P<0.01).ROC analysis showed that rADC and rADCmin thresholds of 2.01 and 1.17, respectively, had the best accuracy:at the rADC threshold of 2.01,the sensitivity and specificity were 89.6% and 89.4%. At the rADCmin threshold of1.17, the sensitivity and specificity were 85.4% and 91.0%. Conclusion:Measuring rADC and rADCmin can provide valuable diagnostic information for the preoperative grading of glioma and can improve the diagnostic accuracy. Partâ…¢:The Role of Diffusion Weighted Imaging in Differential Diagnosis of Brain Matastases Derived from Different Tissue and GlioblastomaObjective:To evaluate the role of diffussion weighted imaging(DWI)and Apparent diffusion coefficient(ADC) in differential diagnosis of different pathological brain matastases and glioblastoma.Materials and methods:We retrospectively analyzed DW MR images(b-value 1000 s/mm2) of 34 cases of brain matastases and 54 cases of glioblastoma, each one had been confirmed by surgery an pathology. The mean ADC and rADC of brain matastases and glioblastoma were measured and compared. We did the receiver operating characteristic (ROC) curve, trying to get the cutoff for the rADC to differentiate between the groups.Indeed we divided the brain matastases into several groups by their pathological subtype, and compared the rADC of these groups.Results:The mean rADC of glioblastoma was lower compared with brain matastases(P<0.01).But The area under the ROC curve is too small.That mean rADC was not a good diagnostic tool to differentiate brain matastases from glioblastoma.Among these 34 cases,17 were adenocarcinoma;5 were squamous carcinoma;5 were clear cell carcinomma;7 were poorly differentiated carcinoma.The mean rADC of poorly differentiated carcinoma was significantly lower than adenocarcinoma and clear cell carcinomma (P<0.01).The mean rADC of glioblastoma was significantly lower than adenocarcinoma and clear cell carcinomma (P<0.01).There was no significant difference among quamous carcinoma,poorly differentiated carcinoma or glioblastoma. Conclusion: rADC plays limited role in differentiating between brain matastases and glioblastoma,but can provide some imformation about primary tumor.