Taylor SA, Slater A, Halligan S, Honeyfield L, Roddie ME, Demeshski J, Amin H, Burling D
CT Colonography: Automated Measurement of Colonic Polyps Compared with Manual Techniques--Human in Vitro Study. [JOURNAL ARTICLE]
Radiology 2006 Nov 14.
Purpose: To prospectively investigate the relative accuracy and reproducibility of manual and automated computer software measurements by using polyps of known size in a human colectomy specimen. Materials and
Methods: Institutional review board approval was obtained for the study; written consent for use of the surgical specimen was obtained. A colectomy specimen containing 27 polyps from a 16-year-old male patient with familial adenomatous polyposis was insufflated, submerged in a container with solution, and scanned at four-section multi-detector row computed tomography (CT). A histopathologist measured the maximum dimension of all polyps in the opened specimen. Digital photographs and line drawings were produced to aid CT-histologic measurement correlation. A novice (radiographic technician) and an experienced (radiologist) observer independently estimated polyp diameter with three methods: manual two-dimensional (2D) and manual three-dimensional (3D) measurement with software calipers and automated measurement with software (automatic). Data were analyzed with paired t tests and Bland-Altman limits of agreement.
Results: Seven polyps (</=6-mm diameter) could not be extracted by using the software; 20 polyps (5-15-mm diameter) remained for analysis. Automated measurement was not significantly different from histologic size for the experienced reader (mean difference, 0.63 mm; P = .06) or novice reader (mean difference, 0.58 mm; P = .12). With manual 2D measurement and manual 3D measurement, the experienced reader (1.21-mm mean difference, P < .001, and 0.68-mm mean difference, P = .03, respectively) and novice reader (1.54-mm mean difference, P < .001, and 0.84-mm mean difference, P = .002, respectively) significantly underestimated polyp size. Interobserver agreement was good and similar for all three methods (95% limits of agreement span, approximately 2.5 mm). Intraobserver agreement was related to reader experience, with differences of up to 2.5 mm within expected limits of agreement.
Conclusion: For polyps smaller than 1 cm, measurement differences of up to 2.5 mm are within the expected limits of inter- and intraobserver agreement for all measurement techniques. Automated and manual 3D polyp measurements are more accurate than manual 2D measurements. (c) RSNA, 2006.
More from this journal |
