title: Diffusion-weighted MRI hyperintensity patterns differentiate CJD from other rapid dementias.
abstract: BACKGROUND
  Diffusion-weighted imaging (DWI) and fluid-attenuated inversion recovery (FLAIR) MRI have high sensitivity and specificity for Creutzfeldt-Jakob disease (CJD). No studies, however, have demonstrated how MRI can distinguish CJD from nonprion causes of rapidly progressive dementia (npRPD). We sought to determine the diagnostic accuracy of MRI for CJD compared to a cohort of npRPD subjects.
  
  
  METHODS
  Two neuroradiologists blinded to diagnosis assessed DWI and FLAIR images in 90 patients with npRPD (n = 29) or prion disease (sporadic CJD [sCJD], n = 48, or genetic prion disease [familial CJD, n = 6, and Gerstmann-Sträussler-Scheinker, n = 7]). Thirty-one gray matter regions per hemisphere were assessed for abnormal hyperintensities. The likelihood of CJD was assessed using our previously published criteria.
  
  
  RESULTS
  Gray matter hyperintensities (DWI > FLAIR) were found in all sCJD cases, with certain regions preferentially involved, but never only in limbic regions, and rarely in the precentral gyrus. In all sCJD cases with basal ganglia or thalamic DWI hyperintensities, there was associated restricted diffusion (apparent diffusion coefficient [ADC] map). This restricted diffusion, however, was not seen in any npRPD cases, in whom isolated limbic hyperintensities (FLAIR > DWI) were common. One reader's sensitivity and specificity for sCJD was 94% and 100%, respectively, the other's was 92% and 72%. After consensus review, the readers' combined MRI sensitivity and specificity for sCJD was 96% and 93%, respectively. Familial CJD had overlapping MRI features with sCJD.
  
  
  CONCLUSIONS
  The pattern of FLAIR/DWI hyperintensity and restricted diffusion can differentiate sCJD from other RPDs with a high sensitivity and specificity. MRI with DWI and ADC should be included in sCJD diagnostic criteria. New sCJD MRI criteria are proposed.
authors.affiliation: Department of Neurology, Memory & Aging Center, University of California, San Francisco, San Francisco, CA 94143-1207, USA.
authors.forename: P
authors.initials: P
authors.lastname: Vitali
authors.forename: E
authors.initials: E
authors.lastname: Maccagnano
authors.forename: E
authors.initials: E
authors.lastname: Caverzasi
authors.forename: R G
authors.initials: RG
authors.lastname: Henry
authors.forename: A
authors.initials: A
authors.lastname: Haman
authors.forename: C
authors.initials: C
authors.lastname: Torres-Chae
authors.forename: D Y
authors.initials: DY
authors.lastname: Johnson
authors.forename: B L
authors.initials: BL
authors.lastname: Miller
authors.forename: M D
authors.initials: MD
authors.lastname: Geschwind
mesh_terms: D001921:Brain / Q000473:pathology; D015331:Cohort Studies; D007562:Creutzfeldt-Jakob Syndrome / Q000175:diagnosis* / Q000473:pathology; D003704:Dementia / Q000175:diagnosis* / Q000473:pathology; D003937:Diagnosis, Differential; D038524:Diffusion Magnetic Resonance Imaging; D016098:Gerstmann-Straussler-Scheinker Disease / Q000175:diagnosis / Q000473:pathology; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008032:Limbic System / Q000473:pathology; D019579:Neocortex / Q000473:pathology; D015588:Observer Variation; D017096:Prion Diseases / Q000473:pathology; D012189:Retrospective Studies