In this variant, the child already has an established diagnosis of Crohn disease, and the patient presents with acute worsening of symptoms. The primary concern is active inflammation resulting in a Crohn disease complication such as fistula development, abscess, or bowel perforation. Transmural inflammation and/or fibrosis may also result in stricture formation associated with luminal stenosis and bowel obstruction. Acute exacerbation of extraintestinal manifestations such as nephrolithiasis, cholelithiasis, and primary sclerosing cholangitis may also be detected [1]. In this variant, the clinical suspicion for other etiologies of abdominal pain is low. CTE provides high diagnostic performance for evaluation of Crohn disease activity in pediatric patients, as in adults, with a sensitivity >80% and a specificity >85% compared with endoscopic and histologic reference [11-13]. These studies directly compared CTE and MRE and did not find any significant difference in performance between the two modalities. Furthermore, a meta-analysis based on 290 patients from 6 studies showed sensitivity and specificity in detecting active small bowel Crohn disease was 85.8% and 83.6%, respectively, with the AUC of 0.898 [14]. CTE imaging features of active Crohn disease inflammation are very similar to those reported for MRE and include mural (eg, wall thickening and hyperenhancement) and perienteric (eg, engorged vasa recta, fibrofatty proliferation, lymphadenopathy) features of disease [15]. A study comparing the performance of different CTE and MRE imaging features compared with histologic reference showed that mural features of disease (wall thickening and hyperenhancement) performed better than perienteric features in evaluating activity and may be more reliable features in cases in which some but not all features of activity are present [16].
Crohn Disease Child. In this variant, the child already has an established diagnosis of Crohn disease, and the patient presents with acute worsening of symptoms. The primary concern is active inflammation resulting in a Crohn disease complication such as fistula development, abscess, or bowel perforation. Transmural inflammation and/or fibrosis may also result in stricture formation associated with luminal stenosis and bowel obstruction. Acute exacerbation of extraintestinal manifestations such as nephrolithiasis, cholelithiasis, and primary sclerosing cholangitis may also be detected [1]. In this variant, the clinical suspicion for other etiologies of abdominal pain is low. CTE provides high diagnostic performance for evaluation of Crohn disease activity in pediatric patients, as in adults, with a sensitivity >80% and a specificity >85% compared with endoscopic and histologic reference [11-13]. These studies directly compared CTE and MRE and did not find any significant difference in performance between the two modalities. Furthermore, a meta-analysis based on 290 patients from 6 studies showed sensitivity and specificity in detecting active small bowel Crohn disease was 85.8% and 83.6%, respectively, with the AUC of 0.898 [14]. CTE imaging features of active Crohn disease inflammation are very similar to those reported for MRE and include mural (eg, wall thickening and hyperenhancement) and perienteric (eg, engorged vasa recta, fibrofatty proliferation, lymphadenopathy) features of disease [15]. A study comparing the performance of different CTE and MRE imaging features compared with histologic reference showed that mural features of disease (wall thickening and hyperenhancement) performed better than perienteric features in evaluating activity and may be more reliable features in cases in which some but not all features of activity are present [16].