title: Reliability and validity of an algorithm for fuzzy tissue segmentation of MRI.
abstract: OBJECTIVE
  A new multistep, volumetric-based tissue segmentation algorithm that results in fuzzy (or probabilistic) voxel description is described. This algorithm is designed to accurately segment gray matter, white matter, and CSF and can be applied to both single channel high resolution and multispectral (multiecho) MR images.
  
  
  METHODS
  The reliability and validity of this method are evaluated by assessing (a) the stability of the algorithm across time, rater, and pulse sequence; (b) the accuracy of the method when applied to both real and synthetic image datasets; and (c) differences in specific tissue volumes between individuals with a specific genetic condition (fragile X syndrome) and normal control subjects.
  
  
  RESULTS
  The algorithm was found to have high reliability, accuracy, and validity. The finding of increased caudate gray matter volume associated with the fragile X syndrome is replicated in this sample.
  
  
  CONCLUSIONS
  Since this segmentation approach incorporates "fuzzy" or probabilistic methods, it has the potential to more accurately address partial volume effects, anatomical variation within "pure" tissue compartments, and more subtle changes in tissue volumes as a result of disease and treatment. The method is a component of software that is available in the public domain and has been implemented on an inexpensive personal computer thus offering an attractive and promising method for determining the status and progression of both normal development and pathology of the CNS.
authors.affiliation: Department of Psychiatry, Stanford University School of Medicine, CA 94305-5719, USA.
authors.forename: A L
authors.initials: AL
authors.lastname: Reiss
authors.forename: J G
authors.initials: JG
authors.lastname: Hennessey
authors.forename: M
authors.initials: M
authors.lastname: Rubin
authors.forename: L
authors.initials: L
authors.lastname: Beach
authors.forename: M T
authors.initials: MT
authors.lastname: Abrams
authors.forename: I S
authors.initials: IS
authors.lastname: Warsofsky
authors.forename: A M
authors.initials: AM
authors.lastname: Liu
authors.forename: J M
authors.initials: JM
authors.lastname: Links
mesh_terms: D000293:Adolescent; D000328:Adult; D000465:Algorithms; D001921:Brain / Q000033:anatomy & histology*; D016022:Case-Control Studies; D002421:Caudate Nucleus / Q000473:pathology; D002555:Cerebrospinal Fluid; D002648:Child; D002675:Child, Preschool; D003198:Computer Simulation; D019992:Databases as Topic; D005260:Female; D005600:Fragile X Syndrome / Q000175:diagnosis / Q000473:pathology; D017143:Fuzzy Logic; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008838:Microcomputers; D019047:Phantoms, Imaging; D011336:Probability; D017150:Public Sector; D015203:Reproducibility of Results; D012984:Software; D013997:Time Factors