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Low-dose CT Using Iterative Reconstruction in Patients With Inflammatory Bowel Disease

The recruitment status of this study is unknown. The completion date has passed and the status has not been verified in more than two years.
Verified November 2010 by University College Cork.
Recruitment status was:  Recruiting
Information provided by:
University College Cork Identifier:
First received: November 18, 2010
Last updated: NA
Last verified: November 2010
History: No changes posted
The purpose of this study is to validate the use of a low-dose computed tomography (CT) protocol and facilitate reduced radiation doses in patients with inflammatory bowel disease (IBD). This is to be achieved using new computer software (Iterative Reconstruction and Automatic Tube Modulation) which will enable low-dose CT imaging at doses equivalent to that of an abdominal radiograph.

Inflammatory Bowel Disease
Crohn's Disease
Ulcerative Colitis

Study Type: Observational
Study Design: Observational Model: Cohort
Time Perspective: Prospective

Resource links provided by NLM:

Further study details as provided by University College Cork:

Primary Outcome Measures:
  • The adequacy of low dose CT in patients with Inflammatory bowel disease compared with standard dose CT [ Time Frame: At the time of CT ] [ Designated as safety issue: No ]
    Radiation dose of a standard CT abdomen and pelvis will be divided into 2 quotients. A low-dose CT scan acquired using automatic tube current modulation (ATM) requiring 10% the dose of a standard abdominal CT and equating to that of a conventional abdominal radiograph. High noise index will be used ensuring reduced mAs. Increased image noise will be overcome by the IR filter. A second CT using 90% of the standard abdominal CT dose will ensure a diagnostic study is acquired.

Secondary Outcome Measures:
  • The correlation of C-reactive protein assay with CT disease severity in inflammatory bowel disease. [ Time Frame: CRP sample on same day as CT ] [ Designated as safety issue: No ]
    The severity of inflammatory bowel disease will also be quantified based on the CT appearances. The disease severity as measured by CT will be correlated with C-reactive protein measured on the day of imaging.

Estimated Enrollment: 250
Study Start Date: June 2010
Estimated Study Completion Date: December 2011
Estimated Primary Completion Date: December 2011 (Final data collection date for primary outcome measure)
Inflammatory bowel disease
Patients with inflammatory bowel disease requiring CT for clinical purposes will be studied.

Detailed Description:

The increasing use of CT has prompted the development of new scanning protocols which reduce radiation doses to patients and minimise the likelihood of radiation related morbidity. The use of disease specific low-dose CT examinations is an emerging method of limiting radiation doses.

Research conducted in Cork University Hospital(CUH) by the current authors has identified a pressing need to reduce radiation doses in patients with IBD. A retrospective study of radiation doses in patients with Crohn's disease demonstrated that increasing numbers of CT exams are performed with average cumulative effective doses rising from 7.9 to 25mSv when the first 5-years of the 15 year study period were compared with the final 5-years. Eight-five percent of the dose during the final 5-year period was due to CT. Younger patients with more severe disease requiring surgery or steroids were more likely to undergo an increased number of exams. 15.5% of patients received cumulative effective doses of greater than 75mSv. This quantity of radiation exposure is associated with a 7.3% increase in mortality from cancer. In addition, patients with Crohn's disease are inherently predisposed to gastrointestinal and hepatobiliary carcinoma and small bowel lymphoma.

As an alternative to CT, IBD patients are frequently imaging with conventional abdominal radiography. The effective dose of a conventional abdominal radiograph (CAR) is approximately 10% that of a standard abdominal CT varying between 0.7 -0.1mSv. The current authors have also investigated the value of CAR. We retrospectively examined over 500 CAR's performed over a 16 year period in patients with IBD. Patients had an average of 3.5 CAR's performed but there were positive findings in less than 30% of exams. Many of these findings were non-specific requiring further investigation. For example separation of bowel loops on a plain radiograph has a wide differential diagnosis including abscess formation, presence of a phlegmonous mass, fibrofatty proliferation, bowel wall thickening and lymphadenopathy.

Patients with inflammatory bowel disease referred to CUH will undergo a modified abdominal CT protocol. The radiation dose of a standard CT abdomen and pelvis will be divided into 2 quotients. Patients will have a low-dose CT scan requiring approximately 10% of the dose of a standard abdominal CT. This equates to the radiation dose of a conventional abdominal radiograph. Patients will be imaged with a second CT exam using 90% of the standard abdominal CT dose ensuring a diagnostic study is acquired. Patients will be given oral and intravenous contrast agents as for a standard CT. Patients will have a C-reactive protein measured on the day of CT and will have their heights and weights also measured at the time of scanning. Patients will have a plain film of abdomen performed prior to CT.


Ages Eligible for Study:   18 Years and older   (Adult, Senior)
Genders Eligible for Study:   All
Accepts Healthy Volunteers:   No
Sampling Method:   Non-Probability Sample
Study Population
Patients under the care of the hospital gastrointestinal services including in-patients and outpatients.

Inclusion Criteria:

  • Adult patients requiring a CT abdomen for clinical purposes will be included

Exclusion Criteria:

  • Pediatric patients
  Contacts and Locations
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Please refer to this study by its identifier: NCT01244386

Cork University Hospital
Cork, Co Cork, Ireland
Sponsors and Collaborators
University College Cork
Principal Investigator: Michael M Maher, MD University College Cork
Study Director: Owen J O'Connor, MD University College Cork
Study Director: Fergus Shanahan, MD University College Cork
  More Information

Responsible Party: Dr Michael M. Maher MD, University College Cork Identifier: NCT01244386     History of Changes
Other Study ID Numbers: 10-CT-Crohn's 
Study First Received: November 18, 2010
Last Updated: November 18, 2010
Health Authority: Ireland: Research Ethics Committee

Keywords provided by University College Cork:
Computed tomography
Iterative reconstruction
Automatic tube current modulation
Crohn's disease
Inflammatory bowel disease
Radiation dose optimization
C reactive protein

Additional relevant MeSH terms:
Crohn Disease
Colitis, Ulcerative
Intestinal Diseases
Inflammatory Bowel Diseases
Gastrointestinal Diseases
Digestive System Diseases
Colonic Diseases processed this record on January 17, 2017