title: Comparative performance of two polyp detection systems on CT colonography.
abstract: OBJECTIVE
  The purpose of our study was to evaluate two current automatic polyp detection systems to determine their sensitivity and false-positive rate in patients who have undergone CT colonography and subsequent endoscopy.
  
  
  METHODS
  We evaluated two polyp detection systems--Polyp Enhanced Viewing (PEV) and the Summers computer-aided detection (CAD) system (National Institutes of Health [NIH]) using a unique cohort of CT colonography examinations: 31 examinations with true-positive lesions identified by radiologists and 34 examinations with false-positive lesions incorrectly identified by radiologists. All patients had reference-standard colonoscopy within 7 days of CT. Candidate lesions were compared with the endoscopic reference standard and prospective radiologist interpretation. The sensitivity and false-positive rates were calculated for each system.
  
  
  RESULTS
  The NIH system had a higher sensitivity than the PEV tool for polyps > or = 1 cm (22/23, 96%; 78-99%, 95% CI vs 14/23, 61%; 38-81%, 95% CI; p = 0.008, respectively). There was no significant difference in the detection of medium-sized polyps 6-9 mm in size (8/13 vs 6/13, p = 0.68, respectively). The PEV tool had an average of 1.18 false-positive detections per patient, whereas the NIH tool had an average of 5.20 false-positive detections per patient, with the PEV tool having significantly fewer false-positive detections in both patient groups (p < 0.001).
  
  
  CONCLUSIONS
  One polyp detection system tended to operate with a higher sensitivity, whereas the other tended to operate with a lower false-positive rate. Prospective trials using polyp detection systems as a primary or secondary means of CT colonography interpretation appear warranted.
authors.affiliation: Department of Radiology, Mayo Clinic, 200 First St. SW, Rochester, MN 55905, USA.
authors.forename: J G
authors.initials: JG
authors.lastname: Fletcher
authors.forename: Fargol
authors.initials: F
authors.lastname: Booya
authors.forename: Ronald M
authors.initials: RM
authors.lastname: Summers
authors.forename: David
authors.initials: D
authors.lastname: Roy
authors.forename: Lutz
authors.initials: L
authors.lastname: Guendel
authors.forename: Bernhard
authors.initials: B
authors.lastname: Schmidt
authors.forename: Cynthia H
authors.initials: CH
authors.lastname: McCollough
authors.forename: Jeff L
authors.initials: JL
authors.lastname: Fidler
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D003111:Colonic Polyps / Q000000981:diagnostic imaging*; D023881:Colonography, Computed Tomographic / Q000379:methods*; D005189:False Positive Reactions; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional; D008297:Male; D008875:Middle Aged; D011857:Radiographic Image Interpretation, Computer-Assisted; D012680:Sensitivity and Specificity