title: Diagnosis of early colorectal cancer invasion depth by quantitative evaluation of the basal indentation in CT colonography.
abstract: OBJECTIVE
  To investigate the feasibility of diagnosing the invasion depth of early colorectal cancer (CRC) by quantitatively evaluating the basal indentation (BI)-i.e., the intestinal lateral deformity-in CT colonography (CTC).
  
  
  METHODS
  34 early CRCs (13 Tis CRCs and 21 T1 CRCs) in 32 patients who underwent a preoperative CTC were retrospectively examined. Two radiologists calculated the depth of the BI on a computed tomographic air-contrast enema (CT enema) image, the depth of the BI due to the geometric function (BI-G) on a cross-sectional multiplanar reconstruction (CS-MPR) image, and the ratio of the BI to the BI-G (i.e., the "BI ratio") for each lesion. The BI ratios of the Tis and T1 CRCs were compared.
  
  
  RESULTS
  The BI ratios were significantly higher in the T1 CRCs than in the Tis CRCs (p < 0.0001). The optimum cutoff value of the BI ratio for differentiating the T1 CRCs from the Tis CRCs was 1.64, with a sensitivity, specificity, and area under the curve of 90.5 %, 100 %, and 0.974, respectively.
  
  
  CONCLUSIONS
  We have demonstrated for the first time that quantitatively evaluating the BI can improve the accuracy of diagnosis of early CRC invasion depth.
authors.affiliation: Department of Clinical Radiology, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan. mmiya@radiol.med.kyushu-u.ac.jp.
authors.forename: Mitsutoshi
authors.initials: M
authors.lastname: Miyasaka
authors.affiliation: Department of Clinical Radiology, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan.
authors.forename: Daisuke
authors.initials: D
authors.lastname: Tsurumaru
authors.affiliation: Department of Clinical Radiology, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan.
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Nishimuta
authors.affiliation: Department of Clinical Radiology, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan.
authors.forename: Yoshiki
authors.initials: Y
authors.lastname: Asayama
authors.affiliation: Department of Molecular Imaging and Diagnosis, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Kawanami
authors.affiliation: Department of Surgery, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan.
authors.forename: Eiji
authors.initials: E
authors.lastname: Oki
authors.affiliation: Department of Anatomic Pathology, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan.
authors.forename: Minako
authors.initials: M
authors.lastname: Hirahashi
authors.affiliation: Department of Clinical Radiology, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Honda
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003106:Colon / Q000000981:diagnostic imaging / Q000473:pathology; D023881:Colonography, Computed Tomographic / Q000379:methods*; D015179:Colorectal Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology*; D055088:Early Detection of Cancer / Q000379:methods*; D005069:Evaluation Studies as Topic; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009361:Neoplasm Invasiveness / Q000000981:diagnostic imaging / Q000473:pathology; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
keywords: Basal indentation; CT colonography; Cross-sectional multiplanar reconstruction; Early colorectal cancer; Geometric function