Thomas C. Lauenstein

Grading luminal Crohn's disease: Which MRI features are considered as important?

OBJECTIVES Magnetic resonance imaging (MRI) is increasingly used for disease activity grading in small bowel Crohns disease. It is not known which imaging features are essential for grading. For further insight, we solicited the opinion of expert radiologists. METHODS A questionnaire about the grading of Crohns disease was sent to 36 radiologists who had published on MRI grading of Crohns disease between January 2006 and January 2010. Radiologists were asked which MRI protocol they used, how they graded luminal Crohns disease, which features they used, how important they considered those features for grading, and which reference standards they used. RESULTS Twenty-four radiologists responded (66%). They used different protocols and features; most frequently T2-weighted sequences (79%) and contrast enhanced fat saturated T1-weighted sequences (83%). MR-enterography was more often used than MR-enteroclysis (88% versus 33%). Features most frequently considered important for grading were bowel wall thickness (79% of radiologists), the presence of an abscess (75%), T1 enhancement (75%), and T1 stratification (46%). Reference standards differed; most commonly (ileo-) colonoscopy (88%) or surgery (75%) were used. CONCLUSIONS Bowel wall thickness, abscess, T1 enhancement and T1 stratification are most often used for grading. Because of difference in grading, there is need for an international consensus on MRI grading of Crohns disease.