title: Increased anisotropy in neonatal meningitis: an indicator of meningeal inflammation.
abstract: BACKGROUND
  Increased anisotropy in brain abscesses has been shown to be due to adhesion of inflammatory cells and is suggestive of an active inflammatory process. The objective of this study was to determine if similar changes occur in the pia-arachnoid on the surface of the cerebral cortex in patients with pyogenic meningitis, and if these changes regress following antibiotic therapy.
  
  
  METHODS
  Diffusion tensor imaging (DTI) was performed on 14 term neonates (mean age 13 days) with bacterial meningitis and 10 healthy age- and sex-matched controls. Regions of interest (ROIs) were placed on areas including the leptomeninges, the cerebral cortex and adjoining subcortical white matter for quantitation of mean fractional anisotropy (FA) and diffusivity (MD) values. Follow-up MRI was performed in five of the neonates in the patient group after 2 weeks of antibiotic treatment. FA and MD values were compared in patients before and after antibiotic treatment as well as with those in the healthy controls.
  
  
  RESULTS
  Significantly higher FA values but no difference in MD values were observed in the patient group as compared to the healthy controls at both time points (before and after antibiotic treatment). Significantly decreased FA values in the frontal, occipital and temporal cortical regions were observed in patients following antibiotic treatment.
  
  
  CONCLUSIONS
  DTI-derived FA may be of value in the noninvasive assessment of meningeal inflammatory activity and treatment response in neonates.
authors.affiliation: Department of Radiodiagnosis, Sanjay Gandhi Post Graduate Institute of Medical Sciences, Lucknow, UP, India.
authors.forename: Richa
authors.initials: R
authors.lastname: Trivedi
authors.forename: Gyanendra K
authors.initials: GK
authors.lastname: Malik
authors.forename: Rakesh K
authors.initials: RK
authors.lastname: Gupta
authors.forename: Amit
authors.initials: A
authors.lastname: Gupta
authors.forename: Kavindra
authors.initials: K
authors.lastname: Nath
authors.forename: Kashi N
authors.initials: KN
authors.lastname: Prasad
authors.forename: Ankur
authors.initials: A
authors.lastname: Purwar
authors.forename: Divya
authors.initials: D
authors.lastname: Rathore
authors.forename: Ram K S
authors.initials: RK
authors.lastname: Rathore
authors.forename: Ponnada A
authors.initials: PA
authors.lastname: Narayana
mesh_terms: D016880:Anisotropy; D000900:Anti-Bacterial Agents / Q000627:therapeutic use*; D002540:Cerebral Cortex / Q000378:metabolism / Q000473:pathology*; D038524:Diffusion Magnetic Resonance Imaging; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007231:Infant, Newborn; D008297:Male; D016920:Meningitis, Bacterial / Q000188:drug therapy / Q000378:metabolism / Q000473:pathology*; D011237:Predictive Value of Tests; D016896:Treatment Outcome
chemical_list: D000900:Anti-Bacterial Agents