Abdominal Imaging

, Volume 32, Issue 1, pp 96–104 | Cite as

Comparison of routine and unprepped CT colonography augmented by low fiber diet and stool tagging: a pilot study

  • Abraham H. Dachman
  • Damien O. Dawson
  • Philippe Lefere
  • Hiro Yoshida
  • Nasreen U. Khan
  • Nicole Cipriani
  • David T. Rubin
Article

Abstract

Background

We performed a pilot study examining the feasibility of a new unprepped CT colonography (CTC) strategy: low fiber diet and tagging (unprepped) vs. low fiber diet, tagging and a magnesium citrate cleansing preparation (prepped). Prior reports of tagging were limited in that the residual stool was neither measured and stratified by size nor did prior reports subjectively evaluate the ease of interpretation by a reader experienced in interpreting CTC examinations.

Methods

Prospective randomized to unprepped n = 14 and prepped n = 14. Colonic segments were subjectively evaluated for residual stool that would potentially interfere with interpretation. Scores were given in the following categories: percentage of residual stool that was touching or nearly touching mucosa, the largest piece of retained stool, effectiveness of tagging, height of residual fluid, degree of distention, ease of interpretation, and reading time.

Results

Ease of the CT read (scale where 4 = optimal read) averaged 1.3 for the unprepped group and 2.3 for the prepped group. The mean read time averaged 17.5 min for unprepped and 17.9 min for prepped. The degree of distention (scale where 4 = well distended) averaged 3.7 for unprepped and 3.6 for prepped. Supine and prone images combined, the unprepped group had 160 segments with stool; prepped group had 58 segments. The amount of stool covering the mucosa in all segments averaged 1.6 (33%–66% coverage) in the unprepped group and 0.35 (<33% mucosal coverage) in the prepped group. The mean size of the largest piece of stool was 33.67 mm for unprepped and 4.01 mm for prepped. Percentage of tagged stool was not significantly different between the groups (range of 94–98%). The height of residual fluid averaged 8.37 mm for unprepped and 13.4 mm for prepped. Three polyps in three patients were found during optical colonoscopy (OC) in the unprepped group (5, 6, and 10 mm), none of which were prospectively detected at CTC. Three polyps in three patients were detected during OC in the prepped group (5, 10, and 15 mm), two of which were prospectively detected at CTC. Two false-positive lesions were observed at CTC in one patient in the prepped group.

Conclusion

There was more stool in the unprepped group and while this factor did not slow down the reading time, it made the examination subjectively harder to interpret and likely caused the three polyps in this group to be missed. We conclude that a truly unprepped strategy that leaves significant residual stool, even if well tagged, is not desirable.

Keywords

CT colonography Colonoscopy Colon cancer CT technique 

Notes

Acknowledgments

This research was funded in part by EZ-EM Inc., American Cancer Society, Illinois Division, Inc., Grant number 03-29, and General Clinical Research Center, NCI Grant number M01RR00055.

References

  1. 1.
    Gryspeerdt S, Lefere P, Herman M, et al. (2005) CT colonography with fecal tagging after incomplete colonoscopy. Eur Radiol 15(6):1192–1202PubMedCrossRefGoogle Scholar
  2. 2.
    Lefere PA, Gryspeerdt SS, Dewyspelaere J, et al. (2002) Dietary fecal tagging as a cleansing method before CT colonography: initial results polyp detection and patient acceptance. Radiology 224(2):393–403PubMedCrossRefGoogle Scholar
  3. 3.
    Bielen D, Thomeer M, Vanbeckevoort D, et al. (2003) Dry preparation for virtual CT colonography with fecal tagging using water-soluble contrast medium: initial results. Eur Radiol 13(3):453–458PubMedGoogle Scholar
  4. 4.
    Thomeer M, Carbone I, Bosmans H, et al. (2003) Stool tagging applied in thin-slice multidetector computed tomography colonography. J Comput Assist Tomogr 27(2):132–139PubMedCrossRefGoogle Scholar
  5. 5.
    Gryspeerdt S, Lefere P, Dewyspelaere J, et al. (2002) Optimisation of colon cleansing prior to computed tomographic colonography. JBR–BTR 85(6):289–296PubMedGoogle Scholar
  6. 6.
    Iannaccone R, Laghi A, Catalano C, et al. (2004) Computed tomographic colonography without cathartic preparation for the detection of colorectal polyps. Gastroenterology 127(5):1300–1311PubMedCrossRefGoogle Scholar
  7. 7.
    Callstrom MR, Johnson CD, Fletcher JG, et al. (2001) CT colonography without cathartic preparation: feasibility study. Radiology 219(3):693–698PubMedGoogle Scholar
  8. 8.
    Thomeer M, Bielen D, Vanbeckevoort D, et al. (2002) Patient acceptance for CT colonography: what is the real issue? Eur Radiol 12(6):1410–1415PubMedCrossRefGoogle Scholar
  9. 9.
    Dachman AH, Kuniyoshi JK, Boyle CM, et al. (1998) CT colonography with three-dimensional problem solving for detection of colonic polyps. AJR 171(4):989–995PubMedGoogle Scholar
  10. 10.
    Macari M, Lavelle M, Pedrosa I, et al. (2001) Effect of different bowel preparations on residual fluid at CT colonography. Radiology 218(1):274–277PubMedGoogle Scholar
  11. 11.
    Pickhardt PJ, Choi JH (2003) Electronic cleansing and stool tagging in CT colonography: advantages and pitfalls with primary three-dimensional evaluation. AJR 181(3):799–805PubMedGoogle Scholar
  12. 12.
    Fidler JL, Johnson CD, MacCarty RL, et al. (2002) Detection of flat lesions in the colon with CT colonography. Abdom Imaging 27(3):292–300PubMedGoogle Scholar
  13. 13.
    Yoshida H, Dachman AH (2005) CAD techniques, challenges, and controversies in computed tomographic colonography. Abdom Imaging 30(1):26–41PubMedCrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media, LLC 2006

Authors and Affiliations

  • Abraham H. Dachman
    • 1
  • Damien O. Dawson
    • 2
  • Philippe Lefere
    • 3
  • Hiro Yoshida
    • 4
  • Nasreen U. Khan
    • 5
  • Nicole Cipriani
    • 1
  • David T. Rubin
    • 6
  1. 1.Department of RadiologyThe University of ChicagoChicagoUSA
  2. 2.Department of RadiologyUniversity of Pittsburgh Medical CenterPittsburghUSA
  3. 3.Department of RadiologyStedelijk ZiekenhuisRoeselareBelgium
  4. 4.Department of RadiologyMassachusetts General Hospital and Harvard Medical SchoolBostonUSA
  5. 5.ChicagoUSA
  6. 6.Department of Medicine, Section of GastroenterologyThe University of ChicagoChicagoUSA

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