European Radiology

, Volume 18, Issue 8, pp 1666–1673

CT colonography: computer-aided detection of morphologically flat T1 colonic carcinoma

  • Stuart A. Taylor
  • Gen Iinuma
  • Yutaka Saito
  • Jie Zhang
  • Steve Halligan
Computer Tomography

Abstract

The purpose was to evaluate the ability of computer-aided detection (CAD) software to detect morphologically flat early colonic carcinoma using CT colonography (CTC). Twenty-four stage T1 colonic carcinomas endoscopically classified as flat (width over twice height) were accrued from patients undergoing staging CTC. Tumor location was annotated by three experienced radiologists in consensus aided by the endosocpic report. CAD software was then applied at three settings of sphericity (0, 0.75, and 1). Computer prompts were categorized as either true positive (overlapping tumour boundary) or false positive. True positives were subclassified as focal or non focal. The 24 cancers were endoscopically classified as type IIa (n=11) and type IIa+IIc (n=13). Mean size (range) was 27 mm (7–70 mm). CAD detected 20 (83.3%), 17 (70.8%), and 13 (54.1%) of the 24 cancers at filter settings of 0, 0.75, and 1, respectively with 3, 4, and 8 missed cancers of type IIa, respectively. The mean total number of false-positive CAD marks per patient at each filter setting was 36.5, 21.1, and 9.5, respectively, excluding polyps. At all settings, >96.1% of CAD true positives were classified as focal. CAD may be effective for the detection of morphologically flat cancer, although minimally raised laterally spreading tumors remain problematic.

Keywords

Colonography Computed tomographic Diagnosis Computer-assisted Colonic neoplasms 

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Copyright information

© European Society of Radiology 2008

Authors and Affiliations

  • Stuart A. Taylor
    • 1
    • 5
  • Gen Iinuma
    • 2
  • Yutaka Saito
    • 3
  • Jie Zhang
    • 4
  • Steve Halligan
    • 1
  1. 1.Department of Specialist X-RayUniversity College HospitalLondonUK
  2. 2.Diagnostic Radiology DivisionNational Cancer Centre HospitalTokyoJapan
  3. 3.Endoscopy DivisionNational Cancer Centre HospitalTokyoJapan
  4. 4.Department of RadiologyBeijing Friendship HospitalXuanwu DistrictChina
  5. 5.Department of ImagingUniversity College HospitalLondonUK

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