title: Mild cognitive impairment: baseline and longitudinal structural MR imaging measures improve predictive prognosis.
abstract: OBJECTIVE
  To assess whether single-time-point and longitudinal volumetric magnetic resonance (MR) imaging measures provide predictive prognostic information in patients with amnestic mild cognitive impairment (MCI).
  
  
  METHODS
  This study was conducted with institutional review board approval and in compliance with HIPAA regulations. Written informed consent was obtained from all participants or the participants' legal guardians. Cross-validated discriminant analyses of MR imaging measures were performed to differentiate 164 Alzheimer disease (AD) cases from 203 healthy control cases. Separate analyses were performed by using data from MR images obtained at one time point or by combining single-time-point measures with 1-year change measures. Resulting discriminant functions were applied to 317 MCI cases to derive individual patient risk scores. Risk of conversion to AD was estimated as a continuous function of risk score percentile. Kaplan-Meier survival curves were computed for risk score quartiles. Odds ratios (ORs) for the conversion to AD were computed between the highest and lowest quartile scores.
  
  
  RESULTS
  Individualized risk estimates from baseline MR examinations indicated that the 1-year risk of conversion to AD ranged from 3% to 40% (average group risk, 17%; OR, 7.2 for highest vs lowest score quartiles). Including measures of 1-year change in global and regional volumes significantly improved risk estimates (P = 001), with the risk of conversion to AD in the subsequent year ranging from 3% to 69% (average group risk, 27%; OR, 12.0 for highest vs lowest score quartiles).
  
  
  CONCLUSIONS
  Relative to the risk of conversion to AD conferred by the clinical diagnosis of MCI alone, MR imaging measures yield substantially more informative patient-specific risk estimates. Such predictive prognostic information will be critical if disease-modifying therapies become available.
  
  
  BACKGROUND
  http://radiology.rsna.org/lookup/suppl/doi:10.1148/radiol.11101975/-/DC1.
authors.affiliation: Department of Radiology, University of California, San Diego, 9500 Gilman Dr, La Jolla, CA 92093, USA. lkmcevoy@ucsd.edu
authors.forename: Linda K
authors.initials: LK
authors.lastname: McEvoy
authors.forename: Dominic
authors.initials: D
authors.lastname: Holland
authors.forename: Donald J
authors.initials: DJ
authors.lastname: Hagler
authors.forename: Christine
authors.initials: C
authors.lastname: Fennema-Notestine
authors.forename: James B
authors.initials: JB
authors.lastname: Brewer
authors.forename: Anders M
authors.initials: AM
authors.lastname: Dale
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000150:complications / Q000175:diagnosis* / Q000473:pathology; D016022:Case-Control Studies; D016009:Chi-Square Distribution; D003072:Cognition Disorders / Q000175:diagnosis* / Q000209:etiology / Q000473:pathology; D016002:Discriminant Analysis; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D011446:Prospective Studies; D012372:ROC Curve; D012680:Sensitivity and Specificity; D016019:Survival Analysis