Epidemiology:
Paediatric inflammatory bowel disease is increasing worldwide with an estimated annual incidence in Europe of 23/100000 person years(1).
In Scotland, incidence of paediatric IBD of 7.82/100000/year. Incidence is increasing with age at presentation decreasing (mean 11.9 years)(2).
Incidence of all subtypes of IBD showed significant increases. Crohn disease (CD) incidence 4.75/100000/year, Ulcerative colitis (UC) 2.06/100000/year and Inflammatory Bowel Disease Unclassified (IBDU) 1.01/100000/year (2).
25% of cases of IBD present in children and young people. Diagnosis is uncommon under 5 years (5% of cases). In patients with new diagnosis off CD, there is an equal incidence of ileitis, colitis and ileocolitis. In UC, 90% of patients demonstrate pancolitis at presentation(3).
Role of radiology in diagnosis of paediatric IBD:
Stomach, proximal duodenum and colon are readily accessible to endoscopy and biopsy
Small bowel is not routinely accessible by endoscopy. Fluoroscopic contrast studies have been superceeded by cross sectional imaging based on:
Time:
Small bowel follow through (SBFT) are long studies. More patient discomfort is seen with small bowel follow through than with SBMRI (6).
Diagnostic accuracy:
SBFT vs ileocolonoscopy demonstrates a sensitivity of SBFT of 45% (7).
SBMRI vs ileocolonoscopy sensitivity of 61-91%
SBMRI vs SBFT shows MRI has higher sensitivity (84% vs 72%) and specificity (97% vs 73%) (8).
Radiation:
SBFT effective dose 1-8-2.2 mSv.
Multidetector CT (MDCT) of the abdomen and pelvis of 3.48 mSv (4). There is now a demonstrable association between childhood diagnostic radiation exposure and malignancy (5).
Thus MRI has become the standard test for assessment of the small bowel in paediatric IBD (6).