 Introduction/Background Crohn disease is an inflammatory condition of the gastrointestinal tract with episodes of exacerbation and remission occurring in children, adolescents, and adults. In a genetically predisposed patient, the underlying mechanism is due to an inappropriate inflammatory reaction to intestinal flora [1-3]. Along with ulcerative colitis, Crohn disease is a common inflammatory bowel disease (IBD) with increasing frequency. The prevalence of IBD is 100 to 200 cases per 100,000 children with approximately 10 new cases per 100,000 children diagnosed each year in the United States [4]. Twenty-five percent of all IBD patients are diagnosed prior to 20 years of age [4]. Of these children with IBD, 18% were diagnosed before 10 years of age [4]. Unlike ulcerative colitis, Crohn disease is characterized by transmural granulomatous inflammation as well as discontinuous or skip lesions that can occur anywhere in the gastrointestinal tract. Any portion of the gastrointestinal tract may be involved, most frequently the small bowel and colon, yet perianal Crohn disease is another common manifestation occurring in 15% to 25% of pediatric patients with Crohn disease [5,6]. Crohn disease diagnosis and treatment depend upon a combination of clinical, laboratory, endoscopic, histological, and imaging findings. Appropriate use of imaging provides critical information in the settings of diagnosis, assessment of acute symptoms, disease surveillance, and therapy monitoring. Although portions of the alimentary tract are accessible by either upper endoscopy or ileocolonoscopy, imaging is necessary for many reasons, including assessment of the bowel (particularly small bowel) not amenable to endoscopy, detection of transmural disease without overlying mucosal abnormality, assessment of extraluminal penetrating and extraintestinal disease, and when diagnostic information is sought without invasive endoscopy [1].
Crohn Disease Child.  Introduction/Background Crohn disease is an inflammatory condition of the gastrointestinal tract with episodes of exacerbation and remission occurring in children, adolescents, and adults. In a genetically predisposed patient, the underlying mechanism is due to an inappropriate inflammatory reaction to intestinal flora [1-3]. Along with ulcerative colitis, Crohn disease is a common inflammatory bowel disease (IBD) with increasing frequency. The prevalence of IBD is 100 to 200 cases per 100,000 children with approximately 10 new cases per 100,000 children diagnosed each year in the United States [4]. Twenty-five percent of all IBD patients are diagnosed prior to 20 years of age [4]. Of these children with IBD, 18% were diagnosed before 10 years of age [4]. Unlike ulcerative colitis, Crohn disease is characterized by transmural granulomatous inflammation as well as discontinuous or skip lesions that can occur anywhere in the gastrointestinal tract. Any portion of the gastrointestinal tract may be involved, most frequently the small bowel and colon, yet perianal Crohn disease is another common manifestation occurring in 15% to 25% of pediatric patients with Crohn disease [5,6]. Crohn disease diagnosis and treatment depend upon a combination of clinical, laboratory, endoscopic, histological, and imaging findings. Appropriate use of imaging provides critical information in the settings of diagnosis, assessment of acute symptoms, disease surveillance, and therapy monitoring. Although portions of the alimentary tract are accessible by either upper endoscopy or ileocolonoscopy, imaging is necessary for many reasons, including assessment of the bowel (particularly small bowel) not amenable to endoscopy, detection of transmural disease without overlying mucosal abnormality, assessment of extraluminal penetrating and extraintestinal disease, and when diagnostic information is sought without invasive endoscopy [1].