Ultra Micro Angiography for Evaluating Activity of Crohn’s Disease in Pediatric Patients: A Prospective Study

Purpose: To investigate the role of Ultra Micro Angiography (UMA) in evaluating Crohn's disease (CD) activity in pediatric patients. Materials and Methods: In this prospective study, pediatric patients diagnosed with CD were included. A Resona A20 ultrasound machine (Mindray Medical Systems, China) was used for all patients. The semi-quantitative scores of color Doppler flow imaging (CDFI) and UMA on the thickest segments of bowel walls were assessed according to Limberg score. The Pediatric Crohn’s Disease Activity Index (PCDAI) was the reference standard to evaluate CD activity. ROC analysis was performed to compare the diagnostic efficiency of Limberg scores between CDFI and UMA. Results: Sixty pediatric CD patients were included and divided into three groups according to PCDAI: Group 1, inactive CD (n = 37); Group 2, mild CD (n = 13); and Group 3, moderate to severe CD (n = 10). By UMA, significant differences of Limberg scores were found between Groups 1 and 3 (P < 0.001), Groups 2 and 3 (P = 0.044), and Groups 1 and 2 (P = 0.029). The combined AUROC of B-mode ultrasound (BMUS) features and UMA features in pediatric CD activity evaluation was 0.934, with 87.0% sensitivity and 94.6% specificity, which was significantly higher than that of the combined BMUS features and CDFI ( P = 0.048). Conclusion: By sensitively depicting the low velocity blood flow signals and displaying microvascular morphologies of the bowel wall, UMA is an effective noninvasive imaging method enabling semi-quantitative evaluation of the activity of CD in pediatric patients.