Radiology
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
QUICK SEARCH:   [advanced]


     

DOI: 10.1148/radiol.2401050984
This Article
Right arrow Figures Only
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Submit a response
Right arrow Alert me when this article is cited
Right arrow Alert me when eLetters are posted
Right arrow Alert me if a correction is posted
Right arrow Citation Map
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Slater, A.
Right arrow Articles by Halligan, S.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Slater, A.
Right arrow Articles by Halligan, S.
(Radiology 2006;240:101-109.)
© RSNA, 2006

Experimental Studies

Colonic Polyps: Effect of Attenuation of Tagged Fluid and Viewing Window on Conspicuity and Measurement—In Vitro Experiment with Porcine Colonic Specimen1

Andrew Slater, MRCP, FRCR, Stuart A. Taylor, MD, MRCP, FRCR, David Burling, MRCP, FRCR, Louise Gartner, MRCP, Julia Scarth, MRCS and Steve Halligan, MD, FRCP, FRCR

1 From the Department of Imaging, University College Hospital, University of London, 250 Euston Rd, London NW1 2BU, England (S.A.T., S.H.); and Department of Intestinal Imaging, St Mark's Hospital, London, England (A.S., D.B., L.G., J.S.). Received June 13, 2005; revision requested August 9; revision received August 22; accepted September 15; final version accepted October 17. Address correspondence to S.A.T. (e-mail: csytaylor{at}yahoo.co.uk).

Purpose: To investigate effect of attenuation of tagged fluid and viewing window on polyp conspicuity and measurement with porcine colonic specimen.

Materials and Methods: Eleven (3–10-mm-diameter) polyps were created in porcine colon and the specimen submerged in saline. Four–detector row CT was performed after gas distension and after filling with six barium sulfate suspensions (attenuation, 100–1000 HU). Two readers independently measured maximal two-dimensional polyp diameter on each data set with the following four viewing windows and window levels and window widths, respectively: colon (–150 HU, 1500 HU), lung (–500 HU, 1500 HU), bone (500 HU, 2500 HU), and abdomen (40 HU, 400 HU). In consensus, polyp conspicuity (compared with air data set) was assigned a grade of 1–4 for each viewing window (grade 1, not seen or barely visible; grade 4, optimally seen). For statistical analysis, conspicuity grades were collapsed to a two-point scale. Data were analyzed with Mann-Whitney, Kruskal-Wallis, and {chi}2 tests.

Results: Accuracy of polyp measurement was independent of viewing window for attenuation of tagged fluid of 100–300 HU but differed significantly for 500–1000 HU (P < .001); that for colonic and bone viewing windows was superior (median size difference, 1.0 mm; interquartile range, 0.5–1.5). Conspicuity differed significantly according to viewing window at all attenuation values (P < .001). For 100–300 HU with abdominal viewing window, 83% (24 of 29) of observations were assigned grade 3 or 4 (best). For 500–1000 HU with bone viewing window, 94% (30 of 32) of observations were assigned grade 3 or 4 (superior). Overall conspicuity was best with bone viewing windows at 700 HU.

Conclusion: Polyp conspicuity and measurement in tagged data sets were optimized at 700 HU with bone viewing windows. At less than 300 HU, conspicuity improved with abdominal viewing windows.

© RSNA, 2006




This article has been cited by other articles:


Home page
 Am. J. Roentgenol.Home page
A. H. de Vries, H. W. Venema, J. Florie, C. Y. Nio, and J. Stoker
Influence of Tagged Fecal Material on Detectability of Colorectal Polyps at CT: Phantom Study
Am. J. Roentgenol., October 1, 2008; 191(4): W181 - W189.
[Abstract] [Full Text] [PDF]