Gastrointestinal

European Radiology

, Volume 21, Issue 2, pp 345-352

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 LimAffiliated withDepartment of Radiology, Seoul National University Bundang HospitalInstitute of Radiation Medicine, Seoul National University College of Medicine, Seoul National University Medical Research Center
  • , Kyoung Ho LeeAffiliated withDepartment of Radiology, Seoul National University Bundang HospitalInstitute of Radiation Medicine, Seoul National University College of Medicine, Seoul National University Medical Research Center Email author 
  • , So Yeon KimAffiliated withDepartment of Radiology, Seoul National University Bundang HospitalInstitute of Radiation Medicine, Seoul National University College of Medicine, Seoul National University Medical Research Center
  • , Kil Joong KimAffiliated withDepartment of Radiation Applied Life Science, Seoul National University College of Medicine
  • , Bohyoung KimAffiliated withSchool of Computer Science and Engineering, Seoul National University
  • , Hyunna LeeAffiliated withSchool of Computer Science and Engineering, Seoul National University
  • , Seong Ho ParkAffiliated withDepartment of Radiology and Research Institute of Radiology, Asan Medical Center, University of Ulsan College of Medicine
  • , Jeffrey H. YanofAffiliated withPhilips Healthcare, CT Clinical Science
  • , Seung-sik HwangAffiliated withDepartment of Social & Preventive Medicine, Inha University School of Medicine
    • , Young Hoon KimAffiliated withDepartment of Radiology, Seoul National University Bundang HospitalInstitute of Radiation Medicine, Seoul National University College of Medicine, Seoul National University Medical Research Center

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Abstract

Objective

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.

Methods

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 (CTDI vol ) 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 CTDI vol and the effect of ATT on image noise while adjusting for other variables including abdominal circumference.

Results

CTDI vol varied from 0.88 to 2.54 mGy. There was no significant correlation between CTDI vol and ATT (p = 0.61). ATT did not significantly affect CTDI vol (p = 0.93), while abdominal circumference was the only factor significantly affecting CTDI vol (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.

Conclusion

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

Keywords

CT colonography Radiation dose Tagging Automatic exposure control