title: Spectrum and Prevalence of Pathological Intracranial Magnetic Resonance Imaging Findings in Acute Bacterial Meningitis.
abstract: OBJECTIVE
  Aim of this study was to determine the spectrum and prevalence of pathological intracranial magnetic resonance imaging (MRI) findings in patients with acute bacterial meningitis.
  
  
  METHODS
  We retrospectively identified all consecutive patients with cerebral spinal fluid proven bacterial meningitis who presented at our neurology department between 2007 and 2012. Pathogenic agents and clinical symptoms were noted. MR-examinations were evaluated regarding presence and localization of pathological signal alterations in the different sequences by two neuroradiologists in consensus.
  
  
  RESULTS
  A total of 136 patients with purulent bacterial meningitis were identified. In 114 cases the bacterial pathogen agent was proven and in 75 patients an MRI was available. In 62 of the 75 (82.7 %) patients meningitis-associated pathologic imaging findings were evident on MRI. Overall, intraventricular signal alterations, i.e., signs of pyogenic ventriculitis, were present in 41 cases (54.7 %), while sulcal signal changes were found in 22 cases (29.3 %). Intraparenchymatous signal alterations affected the cortex in 15 cases (20 %), and the white matter in 20 patients (26.7 %). The diffusion-weighted imaging and fluid attenuated inversion recovery sequences were most sensitive in the detection of these changes and showed any pathologic findings in 67.6 and 79.6 %, respectively. Patients with streptococcal meningitis showed significantly more often (n = 29 of 34, 85.3 %) intraventricular and/or sulcal diffusion restrictions than patients with meningitis caused by other agents (n = 12 of 37, 32.4 %) (p< 0.0001).
  
  
  CONCLUSIONS
  Pathological MR findings are frequently found in patients with acute bacterial meningitis. Intraventricular diffusion restrictions, i.e., signs of pyogenic ventriculitis, are more often found in patients with streptococcal, especially pneumococcal, infection.
authors.affiliation: Department of Neuroradiology, Klinikum Grosshadern, Ludwig-Maximilian-University, Marchioninistrasse 15, 81377, Munich, Germany. nina.lummel@med.uni-muenchen.de.
authors.forename: N
authors.initials: N
authors.lastname: Lummel
authors.affiliation: Department of Neuroradiology, Klinikum Grosshadern, Ludwig-Maximilian-University, Marchioninistrasse 15, 81377, Munich, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Koch
authors.affiliation: Department of Neurology, Klinikum Grosshadern, Ludwig-Maximilian-University, Munich, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Klein
authors.affiliation: Department of Neurology, Klinikum Grosshadern, Ludwig-Maximilian-University, Munich, Germany.
authors.forename: H W
authors.initials: HW
authors.lastname: Pfister
authors.affiliation: Department of Neuroradiology, Klinikum Grosshadern, Ludwig-Maximilian-University, Marchioninistrasse 15, 81377, Munich, Germany.
authors.forename: H
authors.initials: H
authors.lastname: Brückmann
authors.affiliation: Department of Neuroradiology, Klinikum Grosshadern, Ludwig-Maximilian-University, Marchioninistrasse 15, 81377, Munich, Germany.
authors.forename: J
authors.initials: J
authors.lastname: Linn
mesh_terms: D000208:Acute Disease; D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001921:Brain / Q000000981:diagnostic imaging / Q000473:pathology; D005260:Female; D005858:Germany / Q000453:epidemiology; D006801:Humans; D000069544:Infectious Encephalitis / Q000000981:diagnostic imaging* / Q000453:epidemiology* / Q000473:pathology; D008279:Magnetic Resonance Imaging / Q000706:statistics & numerical data*; D008297:Male; D016920:Meningitis, Bacterial / Q000000981:diagnostic imaging* / Q000453:epidemiology* / Q000473:pathology; D008875:Middle Aged; D015995:Prevalence; D015203:Reproducibility of Results; D012307:Risk Factors; D012680:Sensitivity and Specificity
keywords: Acute bacterial meningitis; DWI; FLAIR; Pneumococcal meningitis; Sulcal; Ventriculitis