title: Digital bowel cleansing free colonic polyp detection method for fecal tagging CT colonography.
abstract: OBJECTIVE
  Fecal tagging computed tomographic colonography (ftCTC) reduces the discomfort and the inconvenience of patients associated with bowel cleansing procedures before CT scanning. In conventional colonic polyp detection techniques for ftCTC, a digital bowel cleansing (DBC) technique is applied to detect polyps in tagged fecal materials (TFM). However, DBC removes the surface of soft tissues and hampers polyp detection. We developed a colonic polyp detection method for CT colonographic examination that enables the detection of polyps surrounded by air and polyps surrounded by TFM without DBC.
  
  
  METHODS
  CT values inside the polyps surrounded by air and polyps surrounded by TFM tend to gradually increase (blob structure) and decrease (inverse-blob structure) from outward to inward, respectively. We developed blob and inverse-blob structure enhancement filters based on the eigenvalues of a Hessian matrix to detect polyps using their intensity characteristic. False-positive elimination is performed using three feature values: volume, maximum value of filter outputs, and standard deviation of CT values inside the polyp candidates.
  
  
  RESULTS
  The proposed method is applied to 104 cases of ftCTC images that include 57 polyps larger than 6 mm in diameter. The sensitivity of the method was 91.2% (52/57) with 11.4 false positives per case.
  
  
  CONCLUSIONS
  The proposed method detects polyps with high sensitivity and 11.4 false positives per case without adverse effects on the DBC.
authors.affiliation: Suenaga Laboratory, Graduate School of Information Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi, 464-8603, Japan. moda@suenaga.m.is.nagoya-u.ac.jp
authors.forename: Masahiro
authors.initials: M
authors.lastname: Oda
authors.forename: Takayuki
authors.initials: T
authors.lastname: Kitasaka
authors.forename: Kensaku
authors.initials: K
authors.lastname: Mori
authors.forename: Yasuhito
authors.initials: Y
authors.lastname: Suenaga
authors.forename: Tetsuji
authors.initials: T
authors.lastname: Takayama
authors.forename: Hirotsugu
authors.initials: H
authors.lastname: Takabatake
authors.forename: Masaki
authors.initials: M
authors.lastname: Mori
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Natori
authors.forename: Shigeru
authors.initials: S
authors.lastname: Nawano
mesh_terms: D000465:Algorithms; D001185:Artificial Intelligence; D002400:Cathartics; D003111:Colonic Polyps / Q000000981:diagnostic imaging*; D023881:Colonography, Computed Tomographic / Q000379:methods*; D005243:Feces; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods*; D010363:Pattern Recognition, Automated / Q000379:methods*; D011856:Radiographic Image Enhancement / Q000379:methods*; D011857:Radiographic Image Interpretation, Computer-Assisted / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012815:Signal Processing, Computer-Assisted; D013382:Subtraction Technique
chemical_list: D002400:Cathartics