title: Comparison of magnetic resonance imaging sequences with computed tomography to detect low-grade subarachnoid hemorrhage: Role of fluid-attenuated inversion recovery sequence.
abstract: OBJECTIVE
  To compare computed tomography (CT) with magnetic resonance imaging (MRI) for the presumptive diagnosis and localization of acute and subacute low-grade subarachnoid hemorrhage (SAH).
  
  
  METHODS
  We consecutively enrolled 45 patients clinically suspected of low-grade SAH, comparing them with a control group. We obtained axial nonenhanced CT scans as well as fluid-attenuated inversion recovery (FLAIR) and T2-weighted gradient echo (T2*) MRI sequences at 1.0 T. Two neuroradiologists scrutinized the presence of blood at 26 different regions in the intracranial subarachnoid space (SAS).
  
  
  RESULTS
  Three of 45 patients had normal CT and MRI scans, and SAH was excluded by lumbar puncture. We demonstrated SAH on CT scans in 28 of 42 (66.6%) patients, T2* sequences in 15 of 42 (35.7%) patients, and FLAIR sequences in 42 of 42 (100%) patients. Fluid-attenuated inversion recovery sequences were superior to CT in 16 of the 26 evaluated regions.
  
  
  CONCLUSIONS
  The FLAIR sequence was superior for presumptive diagnosis and localization of acute and subacute low-grade SAH, representing a potential tool in this setting.
authors.affiliation: Section of Radiology, Santa Casa de Misericórdia de São Paulo, São Paulo, Brazil.
authors.forename: Antônio José
authors.initials: AJ
authors.lastname: da Rocha
authors.forename: Carlos Jorge
authors.initials: CJ
authors.lastname: da Silva
authors.forename: Hugo Pereira Pinto
authors.initials: HP
authors.lastname: Gama
authors.forename: Carlos Eduardo
authors.initials: CE
authors.lastname: Baccin
authors.forename: Flávio Túlio
authors.initials: FT
authors.lastname: Braga
authors.forename: Fabiane de Araújo
authors.initials: Fde A
authors.lastname: Cesare
authors.forename: José Carlos Esteves
authors.initials: JC
authors.lastname: Veiga
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016022:Case-Control Studies; D016009:Chi-Square Distribution; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007223:Infant; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D018709:Statistics, Nonparametric; D013345:Subarachnoid Hemorrhage / Q000175:diagnosis* / Q000000981:diagnostic imaging; D014057:Tomography, X-Ray Computed