title: MR quantification of cerebral ventricular volume using a semiautomated algorithm.
abstract: OBJECTIVE
  A semiautomated border identification algorithm, insensitive to user bias, is evaluated for accuracy and speed in the measurement of ventricular volumes from three-dimensional MR images.
  
  
  METHODS
  A three-dimensional gradient-echo technique was implemented on a Signa clinical imaging system. Data from phantoms and patients were analyzed for volume using a segmentation algorithm designed with: 1) correction for partial volume averaging; 2) insensitivity to user bias; and 3) speed. Accuracy, precision, and intra- and interobserver variability were determined.
  
  
  RESULTS
  Average error for phantom studies was 4% to 6%, or 1 to 2 cc across the volumes, which ranged from normal to mild hydrocephalus (< 60 cc). Patient studies showed intra- and interobserver error of 2.3% and 7.8%, respectively. The correction for partial volume averaging resulted in a threefold decrease in error. Data were acquired and reconstructed within 7 minutes. Experienced radiologists required less than 15 minutes to perform each analysis.
  
  
  CONCLUSIONS
  This algorithm allows accurate measurement of ventricular volumes in an efficient, minimally supervised manner.
authors.affiliation: Nuclear Magnetic Resonance Center, Massachusetts General Hospital, Charlestown 02129.
authors.forename: L A
authors.initials: LA
authors.lastname: Johnson
authors.forename: J D
authors.initials: JD
authors.lastname: Pearlman
authors.forename: C A
authors.initials: CA
authors.lastname: Miller
authors.forename: T I
authors.initials: TI
authors.lastname: Young
authors.forename: K R
authors.initials: KR
authors.lastname: Thulborn
mesh_terms: D000328:Adult; D000368:Aged; D002552:Cerebral Ventricles / Q000033:anatomy & histology* / Q000473:pathology; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D008961:Models, Structural; D015588:Observer Variation