@article{oai:sapmed.repo.nii.ac.jp:00008100,
 author = {伊東, 民雄 and 福岡, 誠二 and 岡, 亨治 and 尾崎, 義丸 and 安斉, 公雄 and 大里, 俊明 and 中川原, 譲二 and 中村, 博彦},
 issue = {1},
 journal = {北海道脳神経疾患研究所医誌 = Journal of Hokkaido Brain Research Foundation},
 month = {Mar},
 note = {Object: The purpose of this study is to establish a strategy for dealing with asymptomatic meningiomas (AMs), on the basis of assessing the natural history and treatment results of surgery or Gamma knife radiosurgery (GKRS) for AMs. Methods: We reviewed the imaging studies of the 227 patients with AMs between July 1987 and April 2002. Of these 227 patients, 116 were surgically removed, 41 performed GKRS, and 70 were treated conservatively. Of these conservatively treated patients, 49 received follow-up care for more than 6 months (range 6-104 months). Results: In 12 of these 49 cases, the tumor size increased, but only one developed symptoms related to the meningioma. There was no significant difference in the follow-up periods, sex, or tumor location between patients with and without tumor growth. However, a multivariate analysis revealed that the likelihood of tumor growth significantly increased according to no calcification and younger age. Conclusions: 1. In 70 to 80% of 49 AMs, tumor size did not increased during a 36M average follow-up period. 2. Especially, these tumors with calcification on CT did not increased. 3. In these cases which were no calcification, younger patients, high intensity on T2WI, larger tumor volume with perifocal edema, it is possible to increase in the tumor size, so surgery or  GKRS should be taken into consideration on the good general condition.},
 pages = {1--6},
 title = {無症候性髄膜腫の自然歴と治療適応},
 volume = {13},
 year = {2003}
}