ARRS: MR may emerge as imaging study of choice for kids with Crohns
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MR enterography proved superior to CT enterography in the diagnosis of fibrosis in children with Crohn’s disease and comparable to CT in the detection of active inflammation, according to a study presented April 30 at the annual meeting of the American Roentgen Ray Society in Vancouver.

Pediatric Crohn's patients often have nonspecific symptoms. If their symptoms are due to inflammation, then medical therapy is appropriate. On the other hand, if the symptoms are due to bowel obstruction from fibrosis, then a surgical approach may be necessary.

Keith Quencer, MD, of Massachusetts General Hospital in Boston, and colleagues devised a prospective study of 23 patients with Crohn's disease who underwent CT enterography and MR enterography for symptoms associated with Crohn’s.

Two pediatric radiologists evaluated the MR exams using the CT studies as the reference standard for commonly reported Crohn's imaging features, including lymphadenopathy, bowel wall thickening, mesenteric inflammation and abscess formation. Both imaging datasets were compared to the histologic reference of 51 bowel segments from patients who underwent surgical bowel resection within six weeks of imaging.

According to Quencer and colleagues, MR enterography demonstrated accuracy greater than 80 percent and specificity greater than 90 percent for detecting all Crohn's imaging features studied and compared with CT. MR provided accuracy of 82.1 percent for detecting active inflammation, compared with 77.6 percent for CT. Furthermore, MR delivered accuracy of 77.6 percent for depicting fibrosis, compared with 56.9 percent for CT.  

Quencer highlighted the challenges of the MR vs. CT dilemma.

"While our study shows that MR enterography is as good or better than CT enterography, CT enterography is faster than MR enterography, less expensive and more widely available," he said in a statement. In fact, CT enterography remains the preferred imaging modality to evaluate Crohn's disease.

"We are seeing a change in our practice though," he added, "in part because MR enterography does not use radiation. Crohn disease is a chronic disease, with patients often requiring frequent imaging studies due to symptom recurrence. As we strive to minimize radiation dose, particularly in the pediatric population, MR enterography should be considered.”

The researchers also noted that MR’s superiority over CT for detection of fibrosis could improve management by identifying fibrotic structures that are refractory to medical therapy.