title: Combined diffusion imaging and MR spectroscopy in the diagnosis of human prion diseases.
abstract: OBJECTIVE
  The physiopathologic bases underlying the signal intensity changes and reduced diffusibility observed in prion diseases (TSEs) are still poorly understood. We evaluated the interest of MRS combined with DWI both as a diagnostic tool and a way to understand the mechanism underlying signal intensity and ADC changes in this setting.
  
  
  METHODS
  We designed a prospective study of multimodal MR imaging in patients with suspected TSEs. Forty-five patients with a suspicion of TSE and 11 age-matched healthy volunteers were included. The MR imaging protocol included T1, FLAIR, and DWI sequences. MRS was performed on the cerebellum, pulvinar, right lenticular nucleus, and frontal cortex. MR images were assessed visually, and ADC values were calculated.
  
  
  RESULTS
  Among the 45 suspected cases, 31 fulfilled the criteria for probable or definite TSEs (19 sCJDs, 3 iCJDs, 2 vCJDs, and 7 genetic TSEs); and 14 were classified as AltDs. High signals in the cortex and/or basal ganglia were observed in 26/31 patients with TSEs on FLAIR and 29/31 patients on DWI. In the basal ganglia, high DWI signals corresponded to a decreased ADC. Metabolic alterations, increased mIns, and decreased NAA were observed in all patients with TSEs. ADC values and metabolic changes were not correlated; this finding suggests that neuronal stress (vacuolization), neuronal loss, and astrogliosis do not alone explain the decrease of ADC.
  
  
  CONCLUSIONS
  MRS combined with other MR imaging is of interest in the diagnosis of TSE and provides useful information for understanding physiopathologic processes underlying prion diseases.
authors.affiliation: Department of Neuroradiology, Pitié-Salpêtrière Hospital, Paris, France. galanaud@dat.org
authors.forename: Damien
authors.initials: D
authors.lastname: Galanaud
authors.forename: S
authors.initials: S
authors.lastname: Haik
authors.forename: M G
authors.initials: MG
authors.lastname: Linguraru
authors.forename: J-P
authors.initials: JP
authors.lastname: Ranjeva
authors.forename: B
authors.initials: B
authors.lastname: Faucheux
authors.forename: E
authors.initials: E
authors.lastname: Kaphan
authors.forename: N
authors.initials: N
authors.lastname: Ayache
authors.forename: J
authors.initials: J
authors.lastname: Chiras
authors.forename: P
authors.initials: P
authors.lastname: Cozzone
authors.forename: D
authors.initials: D
authors.lastname: Dormont
authors.forename: J-P
authors.initials: JP
authors.lastname: Brandel
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001927:Brain Diseases / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology; D002531:Cerebellum / Q000378:metabolism / Q000473:pathology; D003342:Corpus Striatum / Q000378:metabolism / Q000473:pathology; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D005625:Frontal Lobe / Q000378:metabolism / Q000473:pathology; D006801:Humans; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D008875:Middle Aged; D017096:Prion Diseases / Q000378:metabolism* / Q000473:pathology* / Q000503:physiopathology; D011446:Prospective Studies; D020649:Pulvinar / Q000378:metabolism / Q000473:pathology; D012680:Sensitivity and Specificity