title: T2*-weighted MR angiography substantially increases the detection of hemorrhage in the wall of brain abscess: implications in clinical interpretation.
abstract: BACKGROUND
  The purpose of the present study was to identify the true prevalence of hemorrhage in the abscess using T2*-weighted angiography (SWAN) imaging and to study its influence on diffusion tensor imaging (DTI) metrics.
  
  
  METHODS
  Fifteen patients of brain abscess underwent conventional, SWAN, and DT imaging on a 3-T MRI followed by its confirmation with histology. DTI metrics were quantified by region-of-interest analysis on hemorrhagic and non-hemorrhagic regions of the abscess wall. Prussian blue staining was performed on excised abscess walls to confirm hemorrhage on histology.
  
  
  RESULTS
  Eleven of 15 patients showed evidence of hemorrhage on both Prussian blue staining as well as SWAN imaging. Fractional anisotropy (FA) and linear anisotropy (CL) values were significantly higher, while spherical anisotropy was significantly lower in hemorrhagic compared to non-hemorrhagic regions of the abscess wall.
  
  
  CONCLUSIONS
  Hemorrhage in the abscess wall is a common feature and may not always indicate neoplasm. The presence of intracellular iron in addition to concentrically laid collagen fibers may have synergistic effect on FA and CL values in the abscess wall. Inclusion of SWAN to MRI protocol will define the true prevalence of hemorrhage in brain abscess.
authors.affiliation: MR Section, Department of Radiodiagnosis, Sanjay Gandhi Post Graduate Institute of Medical Sciences, Lucknow, Uttar Pradesh, 226014, India. rgupta@sgpgi.ac.in
authors.forename: Rakesh Kumar
authors.initials: RK
authors.lastname: Gupta
authors.forename: Vaishali
authors.initials: V
authors.lastname: Tomar
authors.forename: Rishi
authors.initials: R
authors.lastname: Awasthi
authors.forename: Abhishek
authors.initials: A
authors.lastname: Yadav
authors.forename: Nuzhat
authors.initials: N
authors.lastname: Husain
authors.forename: Vikas
authors.initials: V
authors.lastname: Bharadwaj
authors.forename: Bal K
authors.initials: BK
authors.lastname: Ojha
authors.forename: Sanjay
authors.initials: S
authors.lastname: Behari
authors.forename: Kashi N
authors.initials: KN
authors.lastname: Prasad
authors.forename: Ram Kishore Singh
authors.initials: RK
authors.lastname: Rathore
mesh_terms: D000293:Adolescent; D000328:Adult; D001921:Brain / Q000473:pathology*; D001922:Brain Abscess / Q000150:complications* / Q000473:pathology*; D002543:Cerebral Hemorrhage / Q000209:etiology* / Q000473:pathology*; D002648:Child; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D018810:Magnetic Resonance Angiography / Q000379:methods*; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D055815:Young Adult