Kevin Noel O'Regan MD, MRCPI, Presenter: Nothing to Disclose

Desmond Alan, Abstract Co-Author: Nothing to Disclose

Carmel Curran, Abstract Co-Author: Nothing to Disclose

Anne Marie McGarrigle, Abstract Co-Author: Nothing to Disclose

Mannudeep Karanvirsingh Kalra MD, Abstract Co-Author: Nothing to Disclose

Fergus Shanahan, Abstract Co-Author: Nothing to Disclose

Michael M. Maher MD, FRCR, Abstract Co-Author: Nothing to Disclose

et al, Abstract Co-Author: Nothing to Disclose

et al, Abstract Co-Author: Nothing to Disclose

To establish imaging trends in a cohort of patients with Crohn’s disease over a 14-year period and to evaluate the effect of increasing use of CT on the radiation dose received by these patients.

A retrospective analysis was performed with approval from the local ethics committee. 390 patients with Crohn’s disease (Mean age 43 yrs; Range 18- 81; 206F: 184M) referred to a tertiary centre were studied over the time period 1992 to 2006. Demographic data, number and type of radiology examinations, radiation dose parameters for all CT examinations and results of all examinations were recorded. Using data from 1998 to 2006, CTDIw and DLP were calculated using standard CT phantoms for all head, chest and abdominal CT studies. Effective dose was subsequently calculated using conversion factors as published in the European Guidelines, based on ICRP recommendations.

Of 390 patients with Crohn’s Disease referred to our centre from 1992 to 2006, 235 patients underwent radiological investigation. 3616 studies were performed in total, with an average of 15.3 investigations per patient (Range 1-144). A significant increase (7.2-fold) in the use of CT was noted in these patients during the study period with abdominopelvic CT accounting for 81% (268/331) of CT examinations. Barium examinations decreased by 37%. Effective dose per patient from CT examinations ranged from 0.3mSv to 80.6mSv with a mean of 13mSv (S.D. 10.94mSv) per patient over an 8-year study period. About 87% of the CT effective dose was attributable to abdominopelvic CT with doses significantly higher (85.2%) for multislice compared with single slice CT.

Increasing applications and availability of CT for patients with Crohn’s disease has led to a dramatic rise in CT usage, and ultimately, exposure to ionizing radiation in this predominantly young population.

Radiation dose reduction and use of other modalities such as MRI should be considered in these patients.

O'Regan, K, Alan, D, Curran, C, McGarrigle, A, Kalra, M, Shanahan, F, Maher, M, et al, , et al, , Radiation Dose and Imaging Trends in Patient’s with Crohn’s Disease.  Radiological Society of North America 2007 Scientific Assembly and Annual Meeting, November 25 - November 30, 2007 ,Chicago IL. http://archive.rsna.org/2007/5007042.html