Purpose:To determine whether histogram analysis of diffusiontensor (DT) magnetic resonance (MR) imaging metrics, including tensor shape measurements, can help determine the grades and subtypes of meningiomas.
Materials and Methods:The institutional review board approved this HIPAAcompliant study. Nine atypical, three anaplastic, and 39 typical meningiomas were retrospectively studied. The 39 typical meningiomas included one secretory meningioma and 11 fi broblastic, 11 transitional, 14 meningothelial, and two angiomatous meningiomas. DT imaging metrics, including fractional anisotropy, mean diffusivity, linear anisotropy coeffi cient, planar anisotropy coeffi cient (CP), spherical anisotropy coeffi cient (CS), and eigenvalue skewness (SK), as well as normalized signal intensity from contrastenhanced T1-and T2-weighted images, were measured from the enhancing region of the tumor. Mean, variance, skewness, and kurtosis were extracted from the histograms. A two-level decision tree was designed, and a multivariate logistic regression analysis was used at each level to determine the best model for classifi cation.
Results:Histogram skewness of SK and kurtosis of SK were significantly higher in atypical and anaplastic meningiomas than in typical meningiomas ( P , .01). Among typical meningiomas, signifi cant differences in histogram measures of CP and CS between fi broblastic meningiomas and other subtypes were observed ( P , .01). The best model for differentiating atypical and anaplastic meningiomas from typical meningiomas consisted of mean and skewness of SK and kurtosis of T1 signal intensity , with an area under the receiver operating characteristic curve (AUC) of 0.946. The best model for differentiating fi broblastic meningiomas from other subtypes consisted of skewness of T2 signal intensity and kurtosis of CP (AUC, 0.970).
Conclusion:Histogram analysis of DT imaging metrics can help determine the grades and subtypes of meningiomas, which can better assist in surgical planning.q RSNA, 2011Supplemental material: http://radiology.rsna.org/lookup /suppl