PT  - JOURNAL ARTICLE
AU  - Harreld, J.H.
AU  - Zou, P.
AU  - Sabin, N.D.
AU  - Edwards, A.
AU  - Han, Y.
AU  - Li, Y.
AU  - Bieri, O.
AU  - Khan, R.B.
AU  - Gajjar, A.
AU  - Robinson, G.
AU  - Merchant, T.E.
TI  - Pretreatment Normal WM Magnetization Transfer Ratio Predicts Risk of Radiation Necrosis in Patients with Medulloblastoma
AID  - 10.3174/ajnr.A7393
DP  - 2022 Feb 01
TA  - American Journal of Neuroradiology
PG  - 299--303
VI  - 43
IP  - 2
4099  - http://www.ajnr.org/content/43/2/299.short
4100  - http://www.ajnr.org/content/43/2/299.full
SO  - Am. J. Neuroradiol.2022 Feb 01; 43
AB  - BACKGROUND AND PURPOSE: Radiation necrosis, for which abnormal WM enhancement is a hallmark, is an uncommon complication of craniospinal irradiation in children with medulloblastoma. The magnetization transfer ratio measures macromolecular content, dominated by myelin in the WM. We investigated whether the pretreatment supratentorial (nonsurgical) WM magnetization transfer ratio could predict patients at risk for radiation necrosis after radiation therapy for medulloblastoma.MATERIALS AND METHODS: Ninety-five eligible patients with medulloblastoma (41% female; mean age, 11.0 [SD, 5.4]  years) had baseline balanced steady-state free precession MR imaging before proton or photon radiation therapy. Associations among baseline supratentorial magnetization transfer ratio, radiation necrosis (spontaneously resolving/improving parenchymal enhancement within the radiation field)3, age, and the presence of visible brain metastases were explored by logistic regression and parametric/nonparametric techniques as appropriate.RESULTS: Twenty-three of 95 (24.2%) children (44% female; mean age, 10.7 [SD, 6.7] years) developed radiation necrosis after radiation therapy (19 infratentorial, 1 supratentorial, 3 both). The mean pretreatment supratentorial WM magnetization transfer ratio was significantly lower in these children (43.18 versus 43.50, P = .03). There was no association between the supratentorial WM magnetization transfer ratio and age, sex, risk/treatment stratum, or the presence of visible brain metastases.CONCLUSIONS: A lower baseline supratentorial WM magnetization transfer ratio may indicate underlying structural WM susceptibility to radiation necrosis and may identify children at risk for developing radiation necrosis after craniospinal irradiation for medulloblastoma.bSSFPbalanced steady-state free precessionCTCAECommon Terminology Criteria for Adverse EventsM0non-MT-sensitizedMMTMT-sensitizedMTmagnetization transferMTRmagnetization transfer ratioPFSposterior fossa syndromeRNradiation necrosisRTradiation therapySTsupratentorial