title: Multilayer appearance on contrast-enhanced susceptibility-weighted images on patients with brain abscesses: Possible origins and effects of postprocessing.
abstract: OBJECTIVE
  To demonstrate the presence of a multilayer appearance of the capsule on contrast-enhanced (CE) susceptibility-weighted imaging (SWI) in patients with pyogenic brain abscesses. Possible origins for the appearance and effects of postprocessing settings are discussed.
  
  
  METHODS
  Fourteen patients with pyogenic brain abscesses underwent post gadolinium-enhanced SWI at 1.5 T. All SWI images were postprocessed with various filter and mask settings to compare the image appearance. Computer simulations using a paramagnetic spherical shell model were performed to verify the clinical findings.
  
  
  RESULTS
  Pyogenic brain abscesses demonstrated a multilayer appearance with a darkened ring within the enhanced capsule on CE-SWI in all patients. The multilayer appearance was slice-orientation-dependent, decreased with larger widths of the high-pass filter, and increased with larger numbers of phase mask multiplication operations, consistently on both simulation results and the clinical images.
  
  
  CONCLUSIONS
  CE-SWI shows the multilayer appearance of the capsule in pyogenic brain abscesses, which may arise from postprocessing procedures originally designed to enhance susceptibility contrast. Although SWI may provide additional information valuable in the diagnosis of pyogenic brain abscesses, image interpretation should be exercised with caution, particularly for CE-SWI.
authors.affiliation: Graduate Institute of Biomedical Electronics and Bioinformatics, National Taiwan University, Taipei, Taiwan, Republic of China.
authors.forename: Hing-Chiu
authors.initials: HC
authors.lastname: Chang
authors.forename: Tzu-Chao
authors.initials: TC
authors.lastname: Chuang
authors.forename: Hsiao-Wen
authors.initials: HW
authors.lastname: Chung
authors.forename: Huey-Shyan
authors.initials: HS
authors.lastname: Lin
authors.forename: Ping-Hong
authors.initials: PH
authors.lastname: Lai
authors.forename: Mei-Jui
authors.initials: MJ
authors.lastname: Weng
authors.forename: Jui-Hsun
authors.initials: JH
authors.lastname: Fu
authors.forename: Po-Chin
authors.initials: PC
authors.lastname: Wang
authors.forename: Shang-Chieh
authors.initials: SC
authors.lastname: Li
authors.forename: Huay-Ben
authors.initials: HB
authors.lastname: Pan
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D001921:Brain / Q000473:pathology*; D001922:Brain Abscess / Q000473:pathology*; D002648:Child; D002675:Child, Preschool; D003287:Contrast Media; D005260:Female; D005682:Gadolinium; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D055815:Young Adult
chemical_list: D003287:Contrast Media; D005682:Gadolinium