INTRODUCTION: There has been growing interest in the use of MRI in assessing Crohn's disease because of its lack of ionising radiation. Many MRI signs have been described in the literature, but their relative utility is unknown. METHODS: The MRIs of the bowel performed at 1.5 Tesla were blindly reviewed on 26 patients with recent histology (surgery and/or colonoscopy and their associated reports) according to a dedicated pro forma. Each patient's bowel was divided into nine segments. Each segment was assessed as to the presence or absence of 15 MRI signs described in the literature: abnormal gadolinium enhancement (both subjective and objective), wall oedema, fat oedema, fat proliferation, nodal enlargement, free fluid, wall nodularity, serosal blurring, mural thickening >4 mm, stricture, multi-segmental disease, fistula, abscess and layered contrast enhancement. The results were compared against a histological gold standard with a six-point scale of disease severity. RESULTS AND CONCLUSIONS: MRI correctly identified all 15 patients with at least established mucosal disease, and three of eight with only mild mucosal disease. Combining these results, a positive MRI correlated highly with at least early mucosal disease (positive predictive value 95%), while the presence of established mucosal disease was unlikely if MRI was negative (negative predictive value 100%). The MRI signs found to be the most sensitive for detecting active Crohn's disease were those related to the bowel wall, namely, wall thickening, nodularity, contrast enhancement and oedema. The most specific signs were the presence of multi-segmental disease, layered contrast enhancement and complications (fistula and abscess).
INTRODUCTION: There has been growing interest in the use of MRI in assessing Crohn's disease because of its lack of ionising radiation. Many MRI signs have been described in the literature, but their relative utility is unknown. METHODS: The MRIs of the bowel performed at 1.5 Tesla were blindly reviewed on 26 patients with recent histology (surgery and/or colonoscopy and their associated reports) according to a dedicated pro forma. Each patient's bowel was divided into nine segments. Each segment was assessed as to the presence or absence of 15 MRI signs described in the literature: abnormal gadolinium enhancement (both subjective and objective), wall oedema, fat oedema, fat proliferation, nodal enlargement, free fluid, wall nodularity, serosal blurring, mural thickening >4 mm, stricture, multi-segmental disease, fistula, abscess and layered contrast enhancement. The results were compared against a histological gold standard with a six-point scale of disease severity. RESULTS AND CONCLUSIONS: MRI correctly identified all 15 patients with at least established mucosal disease, and three of eight with only mild mucosal disease. Combining these results, a positive MRI correlated highly with at least early mucosal disease (positive predictive value 95%), while the presence of established mucosal disease was unlikely if MRI was negative (negative predictive value 100%). The MRI signs found to be the most sensitive for detecting active Crohn's disease were those related to the bowel wall, namely, wall thickening, nodularity, contrast enhancement and oedema. The most specific signs were the presence of multi-segmental disease, layered contrast enhancement and complications (fistula and abscess).
Authors: Jesica C Makanyanga; Doug Pendsé; Nikolaos Dikaios; Stuart Bloom; Sara McCartney; Emma Helbren; Elaine Atkins; Terry Cuthbertson; Shonit Punwani; Alastair Forbes; Steve Halligan; Stuart A Taylor Journal: Eur Radiol Date: 2013-09-12 Impact factor: 5.315