title: Prognostic value of diffusion tensor imaging parameters for Gamma Knife radiosurgery in meningiomas.
abstract: OBJECTIVE Diffusion tensor imaging (DTI) parameters are able to differentiate between meningioma subtypes. The hypothesis that there is a correlation between DTI parameters and the change in tumor size after Gamma Knife radiosurgery (GKRS) was analyzed. METHODS DTI parameters were measured using MRI before GKRS in 26 patients with meningiomas. The findings were correlated with the change in tumor size after treatment as measured at the last follow-up (range 12.5-45 months). RESULTS Only those meningiomas that showed the highest fractional anisotropy (FA), the lowest spherical index of the tensor ellipsoid (Cs), and the lowest radial diffusivity (RD) either increased or remained stable in terms of volume, whereas all other meningiomas decreased in volume. The correlation between the DTI parameters (correlation values of -0.81 for FA, 0.75 for Cs, 0.66 for RD, and 0.66 for mean diffusivity) and the rate of volume change per month was significant (p ≤ 0.001). Other factors, including original tumor size, prescription dose, and patient age, did not correlate significantly. CONCLUSIONS Meningiomas that show high FA values-as well as low Cs, low RD, and low mean diffusivity values-do not respond as well to GKRS in comparison with meningiomas with low FA values. This finding might be due to their higher content level of fibrous tissue. In particular, the meningioma with the highest FA value (0.444) considerably increased in volume (by 32.3% after 37 months), whereas the meningioma with the lowest FA value (0.151) showed the highest rate of reduction (3.3% per month) in this study.
authors.affiliation: Centro Gamma Knife Dominicano, and.|Radiology, CEDIMAT, Plaza de la Salud, Santo Domingo, Dominican Republic.
authors.forename: Herwin
authors.initials: H
authors.lastname: Speckter
authors.affiliation: Centro Gamma Knife Dominicano, and.
authors.forename: Jose
authors.initials: J
authors.lastname: Bido
authors.affiliation: Centro Gamma Knife Dominicano, and.
authors.forename: Giancarlo
authors.initials: G
authors.lastname: Hernandez
authors.affiliation: Centro Gamma Knife Dominicano, and.
authors.forename: Diones Rivera
authors.initials: DR
authors.lastname: Mejía
authors.affiliation: Centro Gamma Knife Dominicano, and.
authors.forename: Luis
authors.initials: L
authors.lastname: Suazo
authors.affiliation: Centro Gamma Knife Dominicano, and.
authors.forename: Santiago
authors.initials: S
authors.lastname: Valenzuela
authors.affiliation: Departments of 2 Science and.
authors.forename: Eddy
authors.initials: E
authors.lastname: Perez-Then
authors.affiliation: Centro Gamma Knife Dominicano, and.|Radiology, CEDIMAT, Plaza de la Salud, Santo Domingo, Dominican Republic.
authors.forename: Peter
authors.initials: P
authors.lastname: Stoeter
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D056324:Diffusion Tensor Imaging; D005260:Female; D006801:Humans; D008297:Male; D008577:Meningeal Neoplasms / Q000473:pathology / Q000532:radiotherapy*; D008579:Meningioma / Q000473:pathology / Q000532:radiotherapy*; D008875:Middle Aged; D011379:Prognosis; D011446:Prospective Studies; D016634:Radiosurgery / Q000379:methods; D047368:Tumor Burden
keywords: Cl = longitudinal index of the tensor ellipsoid; Cp = planar index of the tensor ellipsoid; Cs = spherical index of the tensor ellipsoid; DTI = diffusion tensor imaging; FA = fractional anisotropy; GKRS = Gamma Knife radiosurgery; Gamma Knife; MD = mean diffusivity; RD = radial diffusivity; diffusion tensor imaging; meningioma; stereotactic radiosurgery