title: Comparison of MR imaging findings in paediatric and adult patients with acute mastoiditis and incidental intramastoid bright signal on T2-weighted images.
abstract: OBJECTIVE
  To compare MR imaging features in patients with incidental mastoid T2-hyperintensity with those of clinical acute mastoiditis, to ascertain characteristic differences between them.
  
  
  METHODS
  MR images of 35 adult and paediatric patients with clinical acute mastoiditis and 34 consecutive age-matched controls without relevant middle ear pathology and with incidental T2-hyperintensity that covered ≥ 50 % of the mastoid were retrospectively analysed with regard to signal, diffusion, and enhancement characteristics, and presence of complications.
  
  
  RESULTS
  Incidental mastoid T2-hyperintensity that covered ≥ 50 % of the mastoid volume was found in 4.6 % of reviewed MR scans (n = 2341), and associated significantly (p < 0.05) less with the involvement of the tympanic cavity (38 % vs. 74 %) and mastoid antrum (56 % vs. 80 %), hypointense-to-CSF signal intensity on T2 FSE (6 % vs. 86 %), intramastoid diffusion restriction (0 % vs. 62 %), intense intramastoid enhancement (0 % vs. 51 %), periosteal enhancement (3 % vs. 69 %), perimastoid dural enhancement 3 % vs. 43 %), bone destruction (0 % vs 49 %), intratemporal abscess or cholesteatoma (0 % vs. 24 %), labyrinth involvement (0 % vs. 14 %), and extracranial abscesses (0 % vs. 20 %).
  
  
  CONCLUSIONS
  Hypointense-to-CSF signal intensity on T2WI, restricted diffusion, intense intramastoid enhancement among other MR imaging characteristics favoured an acute mastoiditis diagnosis over clinically non-relevant incidental mastoid pathology.
  
  
  CONCLUSIONS
  • Intramastoid T2-hyperintensity alone is not a reliable sign for acute mastoiditis. • In acute mastoiditis, intramastoid T2-weighted signal intensity is usually hypointense to CSF. • Diffusion restriction and intense intramastoid enhancement are absent in incidental mastoid effusion. • An ADC value ≥ 1.72 × 10 (-3) mm (2) /s contradicts the AM diagnosis.
authors.affiliation: Department of Radiology, HUS Medical Imaging Centre, Helsinki University Hospital and University of Helsinki, POB 340, Haartmaninkatu 4, Helsinki, 00029, Finland. riste.saat@hus.fi.|Department of Radiology, East Tallinn Central Hospital, Tallinn, Estonia. riste.saat@hus.fi.
authors.forename: R
authors.initials: R
authors.lastname: Saat
authors.affiliation: Department of Radiology, HUS Medical Imaging Centre, Helsinki University Hospital and University of Helsinki, POB 340, Haartmaninkatu 4, Helsinki, 00029, Finland.
authors.forename: G
authors.initials: G
authors.lastname: Mahmood
authors.affiliation: Department of Otorhinolaryngology and Head and Neck Surgery, Helsinki University Hospital and University of Helsinki, Helsinki, Finland.
authors.forename: A
authors.initials: A
authors.lastname: Laulajainen-Hongisto
authors.affiliation: Department of Otorhinolaryngology and Head and Neck Surgery, Helsinki University Hospital and University of Helsinki, Helsinki, Finland.
authors.forename: L
authors.initials: L
authors.lastname: Lempinen
authors.affiliation: Department of Otorhinolaryngology and Head and Neck Surgery, Helsinki University Hospital and University of Helsinki, Helsinki, Finland.
authors.forename: A A
authors.initials: AA
authors.lastname: Aarnisalo
authors.affiliation: Department of Otorhinolaryngology and Head and Neck Surgery, Helsinki University Hospital and University of Helsinki, Helsinki, Finland.
authors.forename: J
authors.initials: J
authors.lastname: Jero
authors.affiliation: Department of Radiology, HUS Medical Imaging Centre, Helsinki University Hospital and University of Helsinki, POB 340, Haartmaninkatu 4, Helsinki, 00029, Finland.
authors.forename: A
authors.initials: A
authors.lastname: Markkola
mesh_terms: D000038:Abscess / Q000000981:diagnostic imaging*; D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D018424:Cholesteatoma, Middle Ear / Q000000981:diagnostic imaging*; D007758:Ear, Inner / Q000000981:diagnostic imaging; D004432:Ear, Middle / Q000000981:diagnostic imaging*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008416:Mastoid / Q000000981:diagnostic imaging; D008417:Mastoiditis / Q000000981:diagnostic imaging*; D008875:Middle Aged; D012189:Retrospective Studies; D055815:Young Adult
keywords: Magnetic resonance imaging; Mastoiditis; Middle ear; Otitis media; Temporal bone