title: Usefulness of the apparent diffusion coefficient for the evaluation of the white matter to differentiate between glioblastoma and brain metastases.
abstract: OBJECTIVE
  To determine whether there are significant differences in the apparent diffusion coefficient (ADC) between the apparently normal peritumor white matter surrounding glioblastomas and that surrounding brain metastases.
  
  
  METHODS
  We retrospectively reviewed 42 patients with histologically confirmed glioblastomas and 42 patients with a single cerebral metastasis. We measured the signal intensity in the apparently normal peritumor white matter and in the abnormal peritumor white matter on the ADC maps. We used mean ADC values in the contralateral occipital white matter as a reference from which to design normalized ADC indices. We compared mean values between the two tumor types. We calculated the area under the receiver operator characteristic curve and estimated the sensitivity and specificity of the measurements taken.
  
  
  RESULTS
  Supratentorial lesions and compromise of the corpus callosum were more common in patients with glioblastoma than in patients with brain metastases. The maximum diameter of the enhanced area after injection of a contrast agent was greater in the glioblastomas (p<0.001). The minimum ADC value measured in the apparently normal peritumor white matter was higher for the glioblastomas than for the metastases (p=0.002). Significant differences in the ADC index were found only for the minimum ADC value in apparently normal peritumor white matter. The sensitivity and specificity were less than 70% for all variables analyzed.
  
  
  CONCLUSIONS
  There are differences in the ADC values of apparently normal peritumor white matter between glioblastomas and cerebral metastases, but the magnitude of these differences is slight and the application of these differences in clinical practice is still limited.
authors.affiliation: Área de Neurorradiología, Servicio de Diagnóstico por Imágenes, Hospital Italiano de Buenos Aires, Ciudad Autónoma de Buenos Aires, Argentina. Electronic address: arielmiquelini@gmail.com.
authors.forename: L A
authors.initials: LA
authors.lastname: Miquelini
authors.affiliation: Área de Neurorradiología, Servicio de Diagnóstico por Imágenes, Hospital Italiano de Buenos Aires, Ciudad Autónoma de Buenos Aires, Argentina.
authors.forename: M S
authors.initials: MS
authors.lastname: Pérez Akly
authors.affiliation: Área de Neurorradiología, Servicio de Diagnóstico por Imágenes, Hospital Italiano de Buenos Aires, Ciudad Autónoma de Buenos Aires, Argentina.
authors.forename: J A
authors.initials: JA
authors.lastname: Funes
authors.affiliation: Área de Neurorradiología, Servicio de Diagnóstico por Imágenes, Hospital Italiano de Buenos Aires, Ciudad Autónoma de Buenos Aires, Argentina.
authors.forename: C H
authors.initials: CH
authors.lastname: Besada
mesh_terms: D001932:Brain Neoplasms / Q000000981:diagnostic imaging* / Q000556:secondary*; D003937:Diagnosis, Differential; D038524:Diffusion Magnetic Resonance Imaging; D005260:Female; D005909:Glioblastoma / Q000000981:diagnostic imaging*; D006801:Humans; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D066127:White Matter / Q000000981:diagnostic imaging*
keywords: Brain; Cerebro; Diffusion magnetic resonance imaging; Difusión por resonancia magnética; Glioblastoma; Metastasis; Metástasis