children Crohn s disease in MR enterography for GI Complications Microscopy Characterization Primary sclerosing cholangitis Anorectal fistulae

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1 MR enterography for Crohn s disease in children BOAZ KARMAZYN, MD PEDIATRIC RADIOLOGY ASSOCIATE PROFESSOR Characterization Crohn disease Idiopathic chronic transmural IBD Increasing incidence Age 7/100,000 in North America years 15-25% present during childhood Mouth to anus Most involve small bowel 10-20% only colonic Transmural Skip lesions Noncaseating granulomas GI Complications Microscopy Fistulae Strictures Anal fissures Perirectal abscesses Anorectal fistulae Primary sclerosing cholangitis Focal inflammation around the crypts Ulceration Crypt abscesses Noncaseating granulomas Extends to all layers Abscesses Fistulas

2 What causes Crohn Disease? Genetic Abnormal immune response Prolonged diarrhea Abdominal pain Weight loss Infection Dietary Psychosocial factors Low grade fever Fatigue Malabsorption Crohn disease Perianal complications Serologic Tests History and physical examination Diarrhea Weight loss Pallor Abdominal tenderness Perianal skin tags, sinus tracts Endoscopy (optical and capsule) Focal ulcerations adjacent to normal mucosa Polypoid changes Intestinal biopsy Focal ulcerations Acute and chronic inflammation Granulomas, up to 30 percent of patients ASCA 50%-70% in Crohn disease Specificity 85-97% 15% in UC 0-5% normal population Higher rate and earlier need for surgery P-ANCA More commonly found in UC Marker of disease activity C reactive protein ESR Fecal calprotectin

3 Diagnosis Extension of disease (small bowel) Activity of disease Complications Intestinal Extra-intestinal Evaluation of remission Barium Small bowel follow through fluoroscopy CT enterography MR enterography Typically a patient will drink 2 cups Computerized tomography

4 Contrast Diluted iodinated contrast IV iodinated contrast Shows enhancement when there is inflammation Oral contrast Delineate the small bowel lumen Positive contrast Neutral contrast Neutral contrast- low concentration Barium VoLumen ( E-Z-EM Inc. New York, NY) 0.1% w/v Barium, 0.1% w/w, 450 ml bottle mixture with Sorbitol Slowly absorbed Shown to have excellent distension over water, MC Generally good pt acceptance Fewer side effects than MC, PEG CT CT enterography The increased radiation from CT is a public health issue

5 MRE became the imaging of choice for Crohn disease Evaluation of extramural complications Sensitivity and specificity Meta-analysis children and adults Sensitivity 78% (95% CI 67% to 84%) Specificity of 85% (95% CI 76% to 90%) Meta-analysis (six pediatric studies) Assessment of disease activity Sensitivity of 84% (95% CI 77% to 90%) Specificity 97% (91% to 99%) Aliment Pharmacol Ther 2011;34: Aliment Pharmacol Ther 2013;37: Change in cross sectional imaging of IBD in Riley ( ) Protocols Coronal HASTE, TrueFisp TrueFisp Cine Axial T2 FS Dynamic post IV contrast Diffusion CT enterography MR enterography Evaluation of peristaltic activity Decrease peristaltic activity is associated with inflamed bowel Menys A. Eur Radiol. 2012;22: T2 TruFisp b = 500 ADC Quantifie terminal ileum motility (n=28) Compared to biopsy Pre- Gad + Gad arterial phase + Gad 50 sec

6 Normal Mild inflammation of the terminal ileum Severe active inflammation of the terminal ileum Free water Normal tissue Inflammed tissue Signal Abnormal tissue Normal tissue Vascular flow b=0 b=50 b= b values

7 Normal structure with restricted diffusion Quantitative measurements of ADC Normal bowel mm 2 /s Inflamed bowel mm 2 /s S S Normal terminal ileum Marked inflamed terminal ileum b=50 ADC Oto A, Acad Radiol 2009;16: Kiryu S, J Magn Reson Imaging 2009;29: Aytekin Oto, MD, J Magn Reson Imaging 20011;33: MRE in evaluation of activity Acute inflammation Complications Intraluminal Strictures Extraluminal Abscess Fistula between bowel loops Perianal fistula Signs of active disease T2 +Gad Wall signal>muscle Early mucosal enhancement Gradual increased wall enhancement Prominent mesenteric vasa recta (comb sign) Signs of fibrosis low bowel wall T2 +Gad Low signal intensity muscle Absent or minimal transmural enhancement 12 year-old boy, Crohn disease +Gad b=500 ADC

8 15 year-old boy, Crohn disease 14 year-old girl, colonic Crohn disease +Gad b=500 ADC +Gad b=500 ADC Mucosal ulcerarations 15 year-old boy, Crohn disease with abscess formation +Gad b=500 ADC Gut 2009;58: year-old girl with Crohn disease and fistula +Gad b=500 ADC

9 Perianal Fistula and Abscess MRI vs endoscopic US MRI better delineate the tract of the fistula Positive and negative predictive values 73% and 87% for MR 57% and 64% for EUA MRI improve surgery outcome Postoperative recurrence 16% if acted on MRI findings 57% if ignored MRI findings AJR Am J Roentgenol 1998; 171: Lancet 2002;360: Perianal Fistula and Abscess About 30% of patients with Crohn have perianal fistula T2 T2 FS T1 FS + Gad T2 T2 T1 FS + Gad T2 FS T1 FS + Gad

10 Limitations of MRI Summary Sedation/GA <4 YO Possible 4-6 YO No oral preparation if sedated Contraindications Ferromagnetic metallic or electronic devices implants Glucagon Contraindications: Pheochromocytoma, insulinoma Emesis Costs MRE became the primary imaging for Crohn disease Diffusion increase sensitivity in detection of active disease Limitations of diffusion False positive findings in the colon Limited in evaluation of fibrosis Future research Standardized reporting (scoring system) Quantitative evaluation (ADC measurements) New techniques Evaluation of remission