title: High-b-value diffusion MR imaging and basal nuclei apparent diffusion coefficient measurements in variant and sporadic Creutzfeldt-Jakob disease.
abstract: OBJECTIVE
  DWI using a standard b-value of 1000 s/mm(2) has emerged as the most sensitive sequence for the diagnosis of CJD. The purpose of this study was to investigate whether DWI at a high b-value (b = 3000 s/mm(2)) and ADC measurements in the basal nuclei improve the diagnosis of vCJD and sCJD compared with visual assessment of DWI at a standard b-value (b = 1000 s/mm(2)).
  
  
  METHODS
  Eight patients with vCJD, 9 patients with sCJD, and 5 healthy volunteers underwent DWI at b = 1000 s/mm(2), and 5 vCJD patients, 4 sCJD patients, and 1 growth hormone-related CJD patient underwent DWI at b = 3000 s/mm(2). Two consultant neuroradiologists performed a visual comparison of the b = 1000 and b = 3000 images. Mean MR SI and ADC values were determined for C, P, and DM thalamus ROIs bilaterally at each b-value. SI ratios for each ROI relative to white matter were calculated.
  
  
  RESULTS
  In 9 out of 10 patients, the higher b-value images were more sensitive to SI change, particularly in cortex and thalamus, with higher SI ratios at b = 3000 in the DM thalamus. For sCJD at b = 1000, we found significantly lower ADC values in the C and P compared with controls (mean C ADC = 587.3 +/- 84.7 mm(2)/s in sCJD patients versus 722.7 +/- 16.6 mm(2)/s in controls; P = .007), and at b = 3000, the differences were more pronounced. In comparison, in vCJD at b = 1000, ADC values were elevated in the Pu (mean Pu ADC = 837.6 +/- 33.0 mm/s(2) in vCJD patients versus 748.0 +/- 17.3 mm/s(2) in controls; P < .001) but failed to reach significance at b = 3000.
  
  
  CONCLUSIONS
  Our results demonstrate that b = 3000 DWI, being more sensitive to slowly diffusing tissue water, is more sensitive to pathology in sCJD than is conventional DWI. High-b-value DWI increases confidence in the radiologic diagnosis of human prion disease.
authors.affiliation: National Prion Clinic, National Hospital for Neurology and Neurosurgery, London, United Kingdom. harpreet.hyare@uclh.nhs.uk
authors.forename: H
authors.initials: H
authors.lastname: Hyare
authors.forename: J
authors.initials: J
authors.lastname: Thornton
authors.forename: J
authors.initials: J
authors.lastname: Stevens
authors.forename: S
authors.initials: S
authors.lastname: Mead
authors.forename: P
authors.initials: P
authors.lastname: Rudge
authors.forename: J
authors.initials: J
authors.lastname: Collinge
authors.forename: T A
authors.initials: TA
authors.lastname: Yousry
authors.forename: H R
authors.initials: HR
authors.lastname: Jäger
mesh_terms: D000328:Adult; D000368:Aged; D001479:Basal Ganglia / Q000378:metabolism* / Q000473:pathology*; D002540:Cerebral Cortex / Q000378:metabolism / Q000473:pathology; D007562:Creutzfeldt-Jakob Syndrome / Q000378:metabolism* / Q000473:pathology*; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012680:Sensitivity and Specificity; D013788:Thalamus / Q000378:metabolism / Q000473:pathology; D014867:Water / Q000378:metabolism; D055815:Young Adult
chemical_list: D014867:Water