Kevin N. O'Regan

Crohn's disease: factors associated with exposure to high levels of diagnostic radiation

Aims: Exposure to diagnostic radiation may be associated with increased risk of malignancy. The aims of this study were: (a) to examine patterns of use of imaging in Crohn9s disease; (b) to quantify the cumulative effective dose (CED) of diagnostic radiation received by patients; and (c) to identify patients at greatest risk of exposure to high levels of diagnostic radiation. Methods: 409 patients with Crohn9s disease were identified at a tertiary centre. CED was calculated retrospectively from imaging performed between July 1992 and June 2007. High exposure was defined as CED>75 milli-Sieverts (mSv), an exposure level which has been reported to increase cancer mortality by 7.3%. Complete data were available for 399 patients. 45 were excluded (20 attended outside study period, 25 primarily managed at other centres). Results: Use of computed tomography increased significantly and accounted for 77.2% of diagnostic radiation. Mean CED was 36.1mSv and exceeded 75mSv in 15.5% of patients. Factors associated with high cumulative exposure were: age 1) surgeries (OR 2.7, CI 1.4-5.4). Conclusions: Identifiable subsets of patients with Crohn9s disease are at risk of exposure to significant amounts of diagnostic radiation. Given the background risk of neoplasia and exposure to potentially synergistic agents such as purine analogues and other immune-modulators, specialist centres should develop low-radiation imaging protocols.

Videoconferencing of a national program for residents on evidence-based practice: early performance evaluation.

PURPOSE The aim of this study was to evaluate the effectiveness of the medium of videoconferencing for the delivery of a course for radiology residents in practice-based learning (PBL), including evidence-based practice, at centers geographically separated from the principal teaching site. MATERIALS AND METHODS Twenty-one participants (second-year radiology residents) at 8 centers in a radiology training program were included. The course in PBL was delivered over 16 weekly 1-hour sessions. There were 8 local education site coordinators (staff radiologists), who had completed an intensive 1-day course at the principal teaching site. The host site was linked to the participant sites using videoconferencing technology. Course evaluation included 1) a 5-point Likert-type scale and an open-ended evaluation questionnaire midway through the course (week 8) and a summation questionnaire after its completion (week 16) and 2) a consultation forum held during the penultimate session. The data responses to the questionnaires were entered in a spreadsheet, and the data were analyzed. Qualitative data were manually coded and analyzed for common themes. Descriptive statistical analyses were performed. RESULTS Eighty-five percent of evaluation questionnaires and 53% of summation questionnaires were returned. The overall satisfaction of the participants with course content was high, with median rating of 4 on the 5-point scale. All participants agreed that videoconferencing as a medium did not hinder adequate discussion among centers and worked well as an interactive teaching method (median, 4). Local coordinators were satisfied with local technical support and training (median, 4), and overall, the module was rated highly, with ratings of 4 from both residents and local coordinators. Seventy-one percent of residents and 86% of local coordinators reported that they would have been unable to participate in the course without videoconferencing. All participants completed the course requirements satisfactorily. The overall rating of audio quality was good (median, 4), but there was dissatisfaction with the quality of the visual aids used. Comments reflected a desire for a shorter, more condensed course; improvement of the quality of visual aids; and more emphasis on research appraisal. CONCLUSION Although videoconferencing is a valuable educational tool and works well as a didactic teaching method, challenges with interactive discussion between centers require further exploration. This technology allows the inclusion of trainers and trainees who may otherwise be unable to participate. In multicenter programs, this can be fundamental to the feasibility and sustainability of educational programs in newer competencies, for which a lack of a critical mass of educators and students can be problematic for individual centers.

Image quality associated with the use of an MR-compatible incubator in neonatal neuroimaging

OBJECTIVES MRI in the neonate poses significant challenges associated with patient transport and monitoring, and the potential for diminished image quality owing to patient motion. The objective of this study was to evaluate the usefulness of a dedicated MR-compatible incubator with integrated radiofrequency coils in improving image quality of MRI studies of the brain acquired in term and preterm neonates using standard MRI equipment. METHODS Subjective and objective analyses of image quality of neonatal brain MR examinations were performed before and after the introduction of an MR-compatible incubator. For all studies, the signal-to-noise ratio (SNR) was calculated, image quality was graded (1-3) and each was assessed for image artefact (e.g. motion). Students t-test and the Mann-Whitney U-test were used to compare mean SNR values. RESULTS 39 patients were included [mean gestational age 39 weeks (range 30-42 weeks); mean postnatal age 13 days (range 1-56 days); mean weight 3.5 kg (range 1.4-4.5 kg)]. Following the introduction of the MR-compatible incubator, diagnostic quality scans increased from 50 to 89% and motion artefact decreased from 73 to 44% of studies. SNR did not increase initially, but, when using MR sequences and parameters specifically tailored for neonatal brain imaging, SNR increased from 70 to 213 (p=0.001). CONCLUSION Use of an MR-compatible incubator in neonatal neuroimaging provides a safe environment for MRI of the neonate and also facilitates patient monitoring and transport. When specifically tailored MR protocols are used, this results in improved image quality.

Selection of Symptomatic Patients With Crohn's Disease for Abdominopelvic Computed Tomography: Role of Serum C-Reactive Protein

Background Results of previous studies have shown that repeated abdominopelvic computed tomography (CT) examinations can lead to substantial cumulative diagnostic radiation exposure in patients with Crohns disease (CD). Improved selection of patients referred for CT will reduce unnecessary radiation exposure. This study examines if serum C-reactive protein (CRP) concentration predicts which symptomatic patients with CD are likely to have significant disease activity or disease complications (such as abscess) detected on abdominopelvic CT. Methods All abdominopelvic CTs performed on patients with CD at a tertiary referral centre during the period June 2003 to June 2008 were identified. CT findings were coded by a pair of independent blinded senior radiologists for (i) small bowel luminal disease, (ii) large bowel luminal disease, (iii) mesenteric inflammatory changes, (iv) penetrating disease (fistulas, abscess, or phlegmon), (v) acute disease complications (obstruction or perforation), and (vi) acute non-CD findings. Imaging findings were correlated with serum CRP checked within 14 days before imaging. The reference range for CRP was defined as 0–5 mg/L. Results A total of 147 patients with symptomatic CD had a CRP assay performed within 14 days before undergoing abdominopelvic CT. The median time from CRP assay to imaging was 2 days (interquartile range, 0-6 days). Median CRP before imaging was 24 mg/L (interquartile range, 6-88 mg/L). CT was normal in 34 of 147 case (23.1%). Patients with normal CRP (n = 36) were significantly less likely to have penetrating disease (odds ratio [OR], 0.04 [95% confidence interval {CI}, 0.01-0.7]; P < .001) or large bowel luminal disease (OR, 0.3 [95% CI, 0.1-0.8]; P < .05). Normal CRP excluded penetrating disease with a sensitivity of 1.0 (95% CI, 0.87-1.0). CRP levels did not correlate with the presence of small bowel luminal disease (n = 82), mesenteric inflammatory changes (n = 68), or acute disease complications (n = 10). Conclusion Symptomatic patients with CD and normal serum CRP are unlikely to have evidence of abscess, fistulating disease, or large bowel luminal disease detected on abdominopelvic CT. However, abdominopelvic CT may demonstrate evidence of clinically significant non-penetrating CD or complications, including perforation and acute obstruction, regardless of serum CRP concentration.

Metastatic meningioma: positron emission tomography CT imaging findings

The imaging findings of a case of metastasing meningioma are described. The case illustrates a number of rare and interesting features. The patient presented with haemoptysis 22 years after the initial resection of an intracranial meningioma. CT demonstrated heterogeneous masses with avid peripheral enhancement without central enhancement. Blood supply to the larger lesion was partially from small feeding vessels from the inferior pulmonary vein. These findings correlate with a previously published case in which there was avid uptake of fluoro-18-deoxyglucose peripherally with lesser uptake centrally. The diagnosis of metastasing meningioma was confirmed on percutaneous lung tissue biopsy.

Sa1132 A Retrospective Cohort Study of Rates of Clostridium difficile Infection in Moderate-to-Severe Inflammatory Bowel Disease Patients Treated With Vedolizumab vs. Infliximab at a Canadian Tertiary Hospital

Background: This study evaluated the long-term safety of adalimumab (ADA), as used in routine clinical practice, for up to 6 years in patients with moderately to severely active Crohns disease (CD) enrolled in the global observational registry PYRAMID. Methods: All patients entering the multi-centre, non-interventional registry PYRAMID were to be followed for up to 6 years. Adverse events (AEs) were collected from the first dose to up to 70 days after the last dose of ADA or through the cutoff of 1 December 2013. AE rates are reported as per 100 patient-years (PY). Results: A total of 5061 patients (57.1% female, mean age 37.8 years, median duration of CD 8.2 years) have enrolled in PYRAMID, totaling 13924.3 PY of ADA exposure, excluding prior exposure in CD ADA clinical trials. As of 01 Dec 2013, 2885 patients (57%) were still participating and 297 patients (5.9%) had at least 6 years of ADA exposure. A total of 2600 patients (51%) received biologic therapy prior to enrollment (98.3% infliximab, 5.6% certolizumab, 1.4% natalizumab, 0.5% other). During the study, concomitant corticosteroids (CS), immunosuppressants (IMM), and IMM + CS were used by 29.4%, 35.6%, and 11.6% of patients, respectively. A total of 682 patients (4.9/100 PY) experienced serious infections, of which 265 patients (5.1/100 PY) were on combination therapy with IMM and 417 patients (4.8/100 PY) were on ADA monotherapy. A total of 104 patients (0.7/100 PY) experienced any malignancy, of which 50% had received combination therapy with IMM. Thirty-eight treatment-emergent deaths (0.3/100 PY) were reported, of which 7 were considered possibly related to ADA. Overall, ADA-exposed patients did not have an increased mortality versus the general population. The Table shows an overview of exposure-adjusted registry treatment-emergent AEs for years 3, 5, and 6. Conclusion: After up to 6 years of observation, long-term ADA exposure continued to be welltolerated in patients with moderately to severely active CD. No new safety signals were identified. AE rates remained stable over time. Table. Cumulative incidence of treatment-emergent adverse events (AEs) excluding prior exposure in other CD ADA trials