European Radiology

, Volume 21, Issue 2, pp 345–352 | Cite as

Does the amount of tagged stool and fluid significantly affect the radiation exposure in low-dose CT colonography performed with an automatic exposure control?

  • Hyun Kyong Lim
  • Kyoung Ho Lee
  • So Yeon Kim
  • Kil Joong Kim
  • Bohyoung Kim
  • Hyunna Lee
  • Seong Ho Park
  • Jeffrey H. Yanof
  • Seung-sik Hwang
  • Young Hoon Kim



To determine whether the amount of tagged stool and fluid significantly affects the radiation exposure in low-dose screening CT colonography performed with an automatic tube-current modulation technique.


The study included 311 patients. The tagging agent was barium (n = 271) or iodine (n = 40). Correlation was measured between mean volume CT dose index (CTDIvol) and the estimated x-ray attenuation of the tagged stool and fluid (ATT). Multiple linear regression analyses were performed to determine the effect of ATT on CTDIvol and the effect of ATT on image noise while adjusting for other variables including abdominal circumference.


CTDIvol varied from 0.88 to 2.54 mGy. There was no significant correlation between CTDIvol and ATT (p = 0.61). ATT did not significantly affect CTDIvol (p = 0.93), while abdominal circumference was the only factor significantly affecting CTDIvol (p < 0.001). Image noise ranged from 59.5 to 64.1 HU. The p value for the regression model explaining the noise was 0.38.


The amount of stool and fluid tagging does not significantly affect radiation exposure.


CT colonography Radiation dose Tagging Automatic exposure control 


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Copyright information

© European Society of Radiology 2010

Authors and Affiliations

  • Hyun Kyong Lim
    • 1
    • 2
  • Kyoung Ho Lee
    • 1
    • 2
  • So Yeon Kim
    • 1
    • 2
  • Kil Joong Kim
    • 3
  • Bohyoung Kim
    • 4
  • Hyunna Lee
    • 4
  • Seong Ho Park
    • 5
  • Jeffrey H. Yanof
    • 6
  • Seung-sik Hwang
    • 7
  • Young Hoon Kim
    • 1
    • 2
  1. 1.Department of RadiologySeoul National University Bundang HospitalSeongnam-siKorea
  2. 2.Institute of Radiation MedicineSeoul National University College of Medicine, Seoul National University Medical Research CenterBundangKorea
  3. 3.Department of Radiation Applied Life ScienceSeoul National University College of MedicineSeoulKorea
  4. 4.School of Computer Science and EngineeringSeoul National UniversitySeoulKorea
  5. 5.Department of Radiology and Research Institute of Radiology, Asan Medical CenterUniversity of Ulsan College of MedicineSeoulKorea
  6. 6.Philips Healthcare, CT Clinical ScienceClevelandUSA
  7. 7.Department of Social & Preventive MedicineInha University School of MedicineIncheonKorea

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