title: Diffusion tensor imaging in evaluation of posterior fossa tumors in children on a 3T MRI scanner.
abstract: BACKGROUND
  Primary intracranial tumors in children are commonly located in the posterior fossa. Conventional MRI offers limited information regarding the histopathological type of tumor which is essential for better patient management.
  
  
  OBJECTIVE
  The purpose of the study was to evaluate the usefulness of advanced MR imaging techniques like diffusion tensor imaging (DTI) in distinguishing the various histopathological types of posterior fossa tumors in children.
  
  
  METHODS
  DTI was performed on a 3T MRI scanner in 34 untreated children found to have posterior fossa lesions.
  
  
  METHODS
  Using third party software, various DTI parameters [apparent diffusion coefficient (ADC), fractional anisotropy (FA), radial diffusivity, planar index, spherical index, and linear index] were calculated for the lesion.
  
  
  METHODS
  Data were subjected to statistical analysis [analysis of variance (ANOVA)] using SPSS 15.0 software.
  
  
  RESULTS
  We observed significant correlation (P < 0.01) between ADC mean and maximum, followed by radial diffusivity (RD) with the histopathological types of the lesions. Rest of the DTI parameters did not show any significant correlation in our study.
  
  
  CONCLUSIONS
  The results of our study support the hypothesis that most cellular tumors and those with greater nuclear area like medulloblastoma would have the lowest ADC values, as compared to less cellular tumors like pilocytic astrocytoma.
authors.affiliation: Department of Radiology, Sri Sathya Sai Institute of Higher Medicial Sciences, Bangalore, Karnataka, India.
authors.forename: Zarina Abdul
authors.initials: ZA
authors.lastname: Assis
authors.affiliation: Department of Neuroimaging and Interventional Radiology, National Institute of Mental Health and Neurosciences, Bangalore, Karnataka, India.
authors.forename: Jitender
authors.initials: J
authors.lastname: Saini
authors.affiliation: Department of Neurosurgery, National Institute of Mental Health and Neurosciences, Bangalore, Karnataka, India.
authors.forename: Manish
authors.initials: M
authors.lastname: Ranjan
authors.affiliation: Department of Neuroimaging and Interventional Radiology, National Institute of Mental Health and Neurosciences, Bangalore, Karnataka, India.
authors.forename: Arun Kumar
authors.initials: AK
authors.lastname: Gupta
authors.affiliation: Department of Neuroimaging and Interventional Radiology, National Institute of Mental Health and Neurosciences, Bangalore, Karnataka, India.
authors.forename: Paramveer
authors.initials: P
authors.lastname: Sabharwal
authors.affiliation: Senior Medical Advisor, Biocon Ltd, Bangalore, Karnataka, India.
authors.forename: Purushotham R
authors.initials: PR
authors.lastname: Naidu
keywords: Apparent diffusion coefficient; children; diffusion tensor imaging; fractional anisotropy; linear index; planar index; posterior fossa tumors; radial diffusivity; spherical index