title: Apparent diffusion coefficient of intracranial germ cell tumors.
abstract: The role of diffusion weighted imaging and apparent diffusion coefficient in intracranial germ cell tumors has not been fully elucidated. The aim of this study was to evaluate whether the ADC correlates with the histologic subtypes of germ cell tumors. We also aimed to investigate whether the ADC values can predict treatment response. The authors retrospectively analyzed the ADC values of the enhancing and solid regions of germ cell tumors. The absolute ADC values and the normalized ADC values were compared among different histologic diagnoses. The ADC values before and after the first course of chemotherapy were also compared between the different prognostic groups. Ten patients were included in the study. The median age at diagnosis was 9.3 years (range 5.3-13.8 years). There were four patients with germinoma and six patients with nongerminomatous germ cell tumor (NGGCT) including five mixed germ cell tumors and one immature teratoma. The mean absolute and normalized ADC values (×10(-3) mm(2)/s) were significantly lower in germinomas [0.835 ± 0.065 (standard deviation) and 1.11 ± 0.096, respectively] than in NGGCTs (1.271 ± 0.145 and 1.703 ± 0.223, respectively) (p = 0.01). The ADC values before and after the first course of chemotherapy were available in four patients. The ADC value after the first chemotherapy had a tendency to increase more in patients who eventually demonstrated complete response with chemotherapy than in patients who required second-look surgery. Assessment of the ADC values of germ cell tumors is considered to facilitate differentiation of histological subtypes of germ cell tumors. Evaluation of the ADC may also be useful for predicting treatment response.
authors.affiliation: Division of Neurosurgery, National Center for Child Health and Development, Okura 2-10-1, Setagaya-ku, Tokyo, 157-8535, Japan, hideki_o@d5.dion.ne.jp.
authors.forename: Hideki
authors.initials: H
authors.lastname: Ogiwara
authors.forename: Yoshiyuki
authors.initials: Y
authors.lastname: Tsutsumi
authors.forename: Kentarou
authors.initials: K
authors.lastname: Matsuoka
authors.forename: Chikako
authors.initials: C
authors.lastname: Kiyotani
authors.forename: Keita
authors.initials: K
authors.lastname: Terashima
authors.forename: Nobuhito
authors.initials: N
authors.lastname: Morota
mesh_terms: D000293:Adolescent; D001932:Brain Neoplasms / Q000473:pathology*; D002648:Child; D002675:Child, Preschool; D038524:Diffusion Magnetic Resonance Imaging; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008297:Male; D009373:Neoplasms, Germ Cell and Embryonal / Q000473:pathology*; D012189:Retrospective Studies