Inflamm Bowel Dis. 2021 Jun 21;izab147. doi: 10.1093/ibd/izab147. Online ahead of print.

Sapir Choshen ¹, Dan Turner ^2 3, Li-Tal Pratt ^4 5, Ronit Precel ⁴, Mary-Louise Greer ^6 7, Denise A Castro ^6 8, Amit Assa ^5 9, María I Martínez-León ¹⁰, Izabela Herman-Sucharska ¹¹, Eva Coppenrath ¹², Osnat Konen ^5 9, Jorge Davila ¹³, Elhamy Bekhit ¹⁴, Zehour Alsabban ¹⁵, Gili Focht ², Matan Gavish ¹⁶, Anne Griffiths ¹⁷, Ruth Cytter-Kuint ¹⁸

Author information

• ¹Pediatric Department, Shaare Zedek Medical Center, Jerusalem, Israel.
• ²The Juliet Keidan Institute of Pediatric Gastroenterology, Shaare Zedek Medical Center, Jerusalem, Israel.
• ³Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel.
• ⁴Pediatric Imaging Unit, Imaging Division, Tel Aviv Sourasky Medical Center, Tel Aviv, Israel.
• ⁵Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.
• ⁶Department of Diagnostic Imaging, Hospital for Sick Children, Toronto, Canada.
• ⁷Department of Medical Imaging, University of Toronto, Toronto, Canada.
• ⁸Department of Diagnostic Radiology, Kingston Health Science Centre, Queen's University, Kingston, Canada.
• ⁹Department of Diagnostic Imaging, Schneider Children's Hospital, Petach-Tikva, Israel.
• ¹⁰Department of Radiology, Hospital Regional Universitario de Málaga, Málaga, Spain.
• ¹¹Department of Radiology, The Voxel Diagnostic Medical Center, Krakow, Poland.
• ¹²University of Munich, Munich, Germany.
• ¹³Department of Medical Imaging, Children's Hospital of Eastern Ontario, Ottawa, Canada.
• ¹⁴Department of Medicine and Radiology, The Royal Children's Hospital, Melbourne, Australia.
• ¹⁵Department of Radiology, King Faisal Specialist Hospital and Research Centre, Jeddah, Saudi Arabia.
• ¹⁶School of Computer Science and Engineering, The Hebrew University, Jerusalem, Israel.
• ¹⁷Department of Gastroenterology, Hospital for Sick Children, University of Toronto, Canada.
• ¹⁸Radiology Department, Shaare Zedek Medical Center, Jerusalem, Israel.

Abstract

Background: As part of the prospective multicenter ImageKids study, we aimed to develop and validate the pediatric MRI-based perianal Crohn disease (PEMPAC) index.

Methods: Children with Crohn disease with any clinical perianal findings underwent pelvic magnetic resonance imaging at 21 sites globally. The site radiologist and 2 central radiologists provided a radiologist global assessment (RGA) on a 100 mm visual analog scale and scored the items selected by a Delphi group of 35 international radiologists and a review of the literature. Two weighted multivariable statistical models were constructed against the RGA.

Results: Eighty children underwent 95 pelvic magnetic resonance imaging scans; 64 were used for derivation and 31 for validation. The following items were included: fistula number, location, length and T2 hyperintensity; abscesses; rectal wall involvement; and fistula branching. The last 2 items had negative beta scores and thus were excluded in a contending basic model. In the validation cohort, the full and the basic models had the same strong correlation with the RGA (r = 0.75; P < 0.01) and with the adult Van Assche index (VAI; r = 0.93 and 0.92; P < 0.001). The correlation of the VAI with the RGA was similar (r = 0.77; P < 0.01). The 2 models and the VAI had a similar ability to differentiate remission from active disease (area under the receiver operating characteristic curve, 0.91-0.94). The PEMPAC index had good responsiveness to change (area under the receiver operating characteristic curve, 0.89; 95% confidence interval, 0.69-1.00).

Conclusions: Using a blended judgmental and mathematical approach, we developed and validated an index for quantifying the severity of perianal disease in children with CD. The adult VAI may also be used with confidence in children.