PURPOSE: To correlate histologic subtypes with MR signal intensity in meniagioma and to find etiologic factors responsible for the signal characteristics of T2WI. MATERIALS AND METHODS: We. reviewed MRIs and histopathologic studies in 35 cases of meningioma. MR signal intenisty was measured with respect to cerebral cortex(gray matter) as hypointense, isointense, or hyperintense. Pathologically, meningioma was classified into subtypes, acording to the new WHO classification of brain tumors. The degree of cellularity, collagen, and vascularity was graded from 1 to 3, and presence or absence of psammoma bodies, microcysts, micronecrosis and microhemorrhage was obeserved. Multiple linear regression analysis was done to find relationship between the pathologic findings and MR signal intensity of T2WI. RESULTS: Even in the same subtype, cellularity, collagen and vascularty of the tumor were different. T1WI was not useful in discriminating pathologic subtype because most tumors were isointense or hypointense to the cortex regardless of histologic type. Most tumors showed various signal intensity on T2WI, but T2WI were not useful, either. Exceptionally, all five cases of microcystic meningiomas were hyperintense on T2W1. In analysing the relationship between MR signal intensity and pathologic factor, increased collagen content produced decreased signal intensity(P<0.01) and the existence of microcyst resulted in high signal intensity(P<0.01). Cellularity, vascularity, microcalcification, micronecrosis and microhemorrhage had no relationship with signal intensity on T2WI. CONCLUSION: Except for the five microcystic meningiomas with hyperintenty on T2WI there was no relationship between MR signal intensity and subtype of meningiomas. Pathologic factors influencing T2 signal intensity were microcyst and collagen. Even in the same subtypes of meningiomas, the T2 signal intensity was different. This may be due to different ratio of microcyst and collagen.