Replacing MR-enterography in lieu of CT-enterography to diagnose Crohn’s disease

By Staff News Brief

CT enterography (CTE) has been the examination of choice for the evaluation of suspected inflammatory bowel disease. MR enterography (MRE) is an excellent substitute for both an initial exam as well as for follow-up exams, say radiologists and gastroenterologists from the Sheba Medical Center in Tel Hashomer, Israel. Additionally, MRE is a safer diagnostic imaging test because patients avoid the high radiation exposure associated with CTE.

MRE is currently recommended over CTE for pediatric patients. But there is increasing concern about performing CTE on pregnant women and young adults, who may undergo multiple CT scans during their lifetime.

The research team, headed by Michal M. Amitai, MD, director of gastrointestinal imaging, conducted a retroactive study of all patients referred for MRE between 2005 and 2009.They wanted to compare the sensitivity of MRE and CTE in the detection of 10 classic imaging features of Crohn’s disease, as well as to compare the accuracy of MRE according to a time interval between an initial CTE and a follow-up MRE. Forty-two patients met the criteria of undergoing both CTE and MRE within a six-month period. They ranged in age from 8 to 51 years, with most in their twenties and thirties. The multiple examinations were ordered for an initial diagnosis, prior to a surgery, and/or because of a change in clinical condition.

The studies were interpreted by two board-certified abdominal radiologists, each with more than 10 years’ experience in abdominal imaging. They did not have access to the patients’ clinical data. The CTE and MRE studies were interpreted in two sessions, one month apart to prevent bias.

The radiologists were asked to report the following 10 typical radiological signs of both mural and extramural findings associated with Crohn’s disease:

  • Mural thickening greater than 3 mm
  • Phlegmon
  • Strictures
  • Presence of multiple simultaneously occurring separate lesions, or skip lesions
  • Mural stratification, the differential enhancement pattern of the bowel wall layers
  • Fistula
  • Abcess
  • Creeping fat, the fatty deposition along the mesenteric border of inflamed bowel segments
  • Luminal dilatation; and,
  • Adenopathy, the presence of nodes greater than 10 mm in diameter, especially if clustered and enhancing.

The study findings were published in the May 2015 issue of the Israeli Medical Association Journal. Dr. Amitai and colleagues determined that CTE and MRE were in agreement more than 70% of the time for eight of the 10 findings. They reported substantial agreement for phlegmon and skip lesions, and moderate but acceptable agreement for detection of fistulae, creeping fat, abscess and mural thickening. Detection was fair for stenosis and dilatation. But there was less than chance agreement for the detection of mucosal stratification and poor agreement for adenopathy.

The MRE images displayed creeping fat and fistula better than did CTE. CTE outperformed with respect to identifying the other eight signs, but the study showed no statistically significant difference in detection for these. The two modalities also proved comparable even when up to six months had elapsed from performance of the first CTE.

“These data support MRE as a reliable imaging modality for the diagnosis and follow-up examinations of Crohn’s disease. Radiologists need to make gastroenterologists aware of this finding, and of the preference and acceptability of ordering this procedure instead of a CTE scan for the young adult population,” concluded Dr. Amitai.

The article may be accessed free of charge here.

REFERENCE

  1. Amitai MM, Raviv-Zilka L, Hertz M et al. Main Imaging Features of Crohn’s Disease: Agreement between MR-Enterography and CT-Enterography. Isr Med Assoc J. 2015;17(5):293-297.
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Replacing MR-enterography in lieu of CT-enterography to diagnose Crohn’s disease.  Appl Radiol. 

By Staff News Brief| August 04, 2015
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