Final Activity Report Summary - RADIATION (Radiation dose associated with computerised tomography in patients with Crohn's disease)
There is increasing concern worldwide regarding radiation exposure to patients as a result of CT scanning. The concern arises from the substantial increase in radiation dose associated with CT scanning compared to other imaging studies such as chest radiographs (plain x-ray (CR)); e.g. the dose of a CT scan of the abdomen and pelvis is equivalent to the dose from 300-500 chest x-rays. The concern regarding radiation dose and CT scanning is compounded by the substantial increase in the use of CT scanning worldwide in the past decade.
The aim of this research programme was to investigate the extent of cumulative radiation exposure, as a result of diagnostic imaging, over a 15-year study period in Crohn's Disease patients (CD) (a benign condition affecting the gastrointestinal tract, characterised by relapsing course, requiring repeated diagnostic examinations including CT scanning, barium studies and plain radiography) and to investigate the contribution CT scanning versus other imaging techniques to overall patient dose. The first stage of the research programme involved a study of 409 patients with CD who were investigated and treated at a single hospital. We found that Identifiable subsets of patients with CD (patients in whom CD was diagnosed at age <17, patients in which CD affected the upper gastrointestinal tract, patients with penetrating disease, patients who required treatment with intravenous steroids or drugs which affect the immune system such as infliximab, patients who have undergone multiple (>1) surgeries were at risk of exposure to significant amounts of diagnostic radiation.
During the next phase, we compared radiation exposure incurred by CD patients versus other groups of inflammatory bowel disease patients (IBD) and found that CD patients incurred the highest radiation dose, followed by patients with indeterminate colitis and that ulcerative colitis patients incurred a much lower radiation dose.
We then investigated the issue of whether the utilisation of CT scanning and resultant patient exposure annually had changed over our 15-year study period and whether changes in CT technology (e.g. multislice CT (MSCT) had impacted such utilisation. The study found that the use of computed tomography increased significantly and accounted for 77.2% of diagnostic radiation exposure. We also found a significant increase in radiation exposure among CD patients with new MSCT technology. This was a very important finding as multislice CT has replaced single slice technology at almost all hospitals across the EU and highlighted the importance of prioritising radiation exposure when designing imaging protocols for MSCT.
Our group also examined novel ways of deciding when a CT is really indicated and will lead to changes in management of CD patients. We investigated the role of serum C-reactive protein (CRP), a biochemical marker of inflammation, which correlates with CD activity. In clinical practice, requests for CT scans are often accompanied by information that CRP level is elevated. We assessed the performance of serum CRP as a predictor for positive CT findings in patients with CD. We showed that with normal CRP, CT is unlikely to show clinically significant disease. These findings may aid in reducing utilisation of CT in CD.
We have also examined the contribution of other imaging modalities, e.g. CR to cumulative radiation exposure in CD patients and have evaluated diagnostic yield of this modality in CD patients. The findings of our study have suggested that CR have a low diagnostic yield in CD and have limited impact on management and given the exposure to ionising radiation, clinicians should be selective when ordering CR for CD patients.
The last component of our research programme has focused on education of undergraduate medical students in radiation protection. The first part of this programme surveyed undergraduate medical students' knowledge of radiation exposure associated with a range of imaging investigations on entry to medical school and at end of each year of 5-year medical undergraduate programme (MUGP). We found improvements in awareness of radiation protection as students progressed through MUGP but levels of knowledge were disappointing even in final year. We therefore introduced a compulsory E-learning module in year 3 of MUGP. We assessed the impact of this module by surveying students' knowledge before and following completion of programme. The study is still a work-in-progress but already the study was awarded the Radiological Society of Ireland Medical Audit Prize in Sept 2009.
The aim of this research programme was to investigate the extent of cumulative radiation exposure, as a result of diagnostic imaging, over a 15-year study period in Crohn's Disease patients (CD) (a benign condition affecting the gastrointestinal tract, characterised by relapsing course, requiring repeated diagnostic examinations including CT scanning, barium studies and plain radiography) and to investigate the contribution CT scanning versus other imaging techniques to overall patient dose. The first stage of the research programme involved a study of 409 patients with CD who were investigated and treated at a single hospital. We found that Identifiable subsets of patients with CD (patients in whom CD was diagnosed at age <17, patients in which CD affected the upper gastrointestinal tract, patients with penetrating disease, patients who required treatment with intravenous steroids or drugs which affect the immune system such as infliximab, patients who have undergone multiple (>1) surgeries were at risk of exposure to significant amounts of diagnostic radiation.
During the next phase, we compared radiation exposure incurred by CD patients versus other groups of inflammatory bowel disease patients (IBD) and found that CD patients incurred the highest radiation dose, followed by patients with indeterminate colitis and that ulcerative colitis patients incurred a much lower radiation dose.
We then investigated the issue of whether the utilisation of CT scanning and resultant patient exposure annually had changed over our 15-year study period and whether changes in CT technology (e.g. multislice CT (MSCT) had impacted such utilisation. The study found that the use of computed tomography increased significantly and accounted for 77.2% of diagnostic radiation exposure. We also found a significant increase in radiation exposure among CD patients with new MSCT technology. This was a very important finding as multislice CT has replaced single slice technology at almost all hospitals across the EU and highlighted the importance of prioritising radiation exposure when designing imaging protocols for MSCT.
Our group also examined novel ways of deciding when a CT is really indicated and will lead to changes in management of CD patients. We investigated the role of serum C-reactive protein (CRP), a biochemical marker of inflammation, which correlates with CD activity. In clinical practice, requests for CT scans are often accompanied by information that CRP level is elevated. We assessed the performance of serum CRP as a predictor for positive CT findings in patients with CD. We showed that with normal CRP, CT is unlikely to show clinically significant disease. These findings may aid in reducing utilisation of CT in CD.
We have also examined the contribution of other imaging modalities, e.g. CR to cumulative radiation exposure in CD patients and have evaluated diagnostic yield of this modality in CD patients. The findings of our study have suggested that CR have a low diagnostic yield in CD and have limited impact on management and given the exposure to ionising radiation, clinicians should be selective when ordering CR for CD patients.
The last component of our research programme has focused on education of undergraduate medical students in radiation protection. The first part of this programme surveyed undergraduate medical students' knowledge of radiation exposure associated with a range of imaging investigations on entry to medical school and at end of each year of 5-year medical undergraduate programme (MUGP). We found improvements in awareness of radiation protection as students progressed through MUGP but levels of knowledge were disappointing even in final year. We therefore introduced a compulsory E-learning module in year 3 of MUGP. We assessed the impact of this module by surveying students' knowledge before and following completion of programme. The study is still a work-in-progress but already the study was awarded the Radiological Society of Ireland Medical Audit Prize in Sept 2009.