title: Differentiation of brain abscesses from necrotic glioblastomas and cystic metastatic brain tumors with diffusion tensor imaging.
abstract: OBJECTIVE
  The differentiation of abscesses from glioblastomas and metastases may not always be possible on the basis of DWI. Our hypothesis was that differences in diffusion properties as detected by DTI allow differentiation of abscess from glioblastomas and metastasis. Furthermore, diagnostic performance of tensor metrics quantifying anisotropy or tensor shapes is better than that of ADC in measuring mean diffusivity for this purpose.
  
  
  METHODS
  DTI was performed in 15 abscesses, 15 necrotic glioblastomas, and 26 cystic metastases. In each lesion, manually segmented into 4 regions of interest (ie, cystic cavity, enhancing rim, and immediate [edema most adjacent to the enhancing rim] and distant zones of edema), FA, ADC, C(l), C(p), and C(s) values were measured and statistically compared among groups and evaluated with ROC curve analysis. The presence of a hyperintense FA rim (a rim of edematous tissue that was hyperintense on the FA map) was assessed visually.
  
  
  RESULTS
  Abscess was significantly different from glioblastoma for all tensor metrics measured in the cystic cavity and immediate zone of edema and for all except C(l) in the enhancing rim. Abscess was significantly different from metastasis for all tensor metrics measured in the cystic cavity and enhancing rim and for FA, ADC, and C(l) in immediate zone of edema. The incidence of a hyperintense FA rim was significantly higher in glioblastoma and metastasis compared with abscess. The 3 tensor metrics with the highest performance in differentiating abscess from glioblastoma and metastasis were FA, C(l), and C(s) of the cystic cavity.
  
  
  CONCLUSIONS
  DTI is able to differentiate abscess from glioblastoma and metastasis. FA, C(l), and C(s) outperformed ADC in diagnostic performance comparisons.
authors.affiliation: Department of Medical Imaging and Intervention, Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Tao-Yuan, Taiwan.
authors.forename: C H
authors.initials: CH
authors.lastname: Toh
authors.forename: K-C
authors.initials: KC
authors.lastname: Wei
authors.forename: S-H
authors.initials: SH
authors.lastname: Ng
authors.forename: Y-L
authors.initials: YL
authors.lastname: Wan
authors.forename: C-P
authors.initials: CP
authors.lastname: Lin
authors.forename: M
authors.initials: M
authors.lastname: Castillo
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D016880:Anisotropy; D001922:Brain Abscess / Q000473:pathology*; D001929:Brain Edema / Q000473:pathology; D001932:Brain Neoplasms / Q000473:pathology* / Q000556:secondary*; D003560:Cysts / Q000473:pathology; D003937:Diagnosis, Differential; D056324:Diffusion Tensor Imaging / Q000379:methods*; D005260:Female; D005909:Glioblastoma / Q000473:pathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D008959:Models, Neurological; D009336:Necrosis / Q000473:pathology; D055815:Young Adult