title: Evaluation of an expert system on lymph node pathology.
abstract: BACKGROUND
  Pathfinder is an Expert System that assists pathologists in making accurate diagnoses in the domain of lymph-node pathology. Pathfinder provides a differential diagnosis based on the initial histological feature(s) observed by the pathologist, and suggests to the user additional histological features for observation that are likely to narrow the differential diagnosis.
  
  
  OBJECTIVE
  To evaluate the diagnostic accuracy of pathologists with and without the Pathfinder.
  
  
  METHODS
  Thirty H&E stained slides from 30 lymph node biopsy specimens on which a Consensus diagnosis was made by two experts were reviewed by 19 pathologists to evaluate Pathfinder. After a period of training, 10 pathologists using Pathfinder (Interactive Computer Method) and 9 pathologists using the Routine Method (diagnosis without computer) determined a differential diagnosis for 15 slides (Test 1). Pathologists were then crossed over, trained, and evaluated the remaining 15 slides (Test 2). For each test, the proportion of "correct" diagnoses was compared between methods. In addition, the information integration attributes (making logical diagnosis given a set of specific histologic features) of Pathfinder and pathologists were compared. Finally, feature identification and quantification skills of pathologists were determined and correlated with the percent correct diagnosis.
  
  
  RESULTS
  The diagnostic accuracy using Pathfinder was greater than that using the Routine Method (40% v 32%, P = .02). Diagnostic accuracy for the group of pathologists who made diagnosis using the Routine Method in Test 1 increased when they made diagnosis using Pathfinder in Test 2 (27% to 44%, P < .0001). The proportion of correct diagnosis for the group of pathologists who used Pathfinder in Test 1 remained virtually unchanged when they gave up Pathfinder in Test 2 (35% to 37%). The percentage of incompatible feature identification ("atypical proliferation" diagnosis) was significantly lower after using Pathfinder (P < .0001). In addition, information integration attributes of Pathfinder were significantly superior than that of the pathologists (P < .0001).
  
  
  CONCLUSIONS
  Pathfinder is a valuable tool that assists pathologists in making accurate diagnosis because it has superior attributes than pathologists to integrate information and to screen for observations incompatible with any specific disease.
authors.affiliation: Department of Pathology, University of Southern California School of Medicine, USA.
authors.forename: B N
authors.initials: BN
authors.lastname: Nathwani
authors.forename: K
authors.initials: K
authors.lastname: Clarke
authors.forename: T
authors.initials: T
authors.lastname: Lincoln
authors.forename: C
authors.initials: C
authors.lastname: Berard
authors.forename: C
authors.initials: C
authors.lastname: Taylor
authors.forename: K C
authors.initials: KC
authors.lastname: Ng
authors.forename: R
authors.initials: R
authors.lastname: Patil
authors.forename: M C
authors.initials: MC
authors.lastname: Pike
authors.forename: S P
authors.initials: SP
authors.lastname: Azen
mesh_terms: D001706:Biopsy; D003661:Decision Support Techniques; D003936:Diagnosis, Computer-Assisted / Q000295:instrumentation*; D003937:Diagnosis, Differential; D005069:Evaluation Studies as Topic; D005103:Expert Systems / Q000295:instrumentation*; D006801:Humans; D008198:Lymph Nodes / Q000473:pathology*; D008206:Lymphatic Diseases / Q000473:pathology; D008223:Lymphoma / Q000473:pathology*; D010338:Pathology, Clinical / Q000295:instrumentation* / Q000379:methods