DOP029. Assessment of wall inflammation and fibrosis in Crohn's disease and its correlation with bowel sonography and MRI-enterography
A. Rispo1, P.P. Mainenti2, F.P. D'Armiento3, A. Testa1, M. Rea1, D. Musto1, M. Diaferia1, L. Bucci4, G. Pesce5, F. Castiglione1, 1AOU Policlinico Federico II of Naples, Gastroenterology, Naples, Italy, 2AOU Policlinico Federico II of Naples, Radiology, Naples, Italy, 3AOU Policlinico Federico II of Naples, Pathology, Naples, Italy, 4AOU Policlinico Federico II of Naples, Colorectal Surgery, Naples, Italy, 5AOU Policlinico Federico II of Naples, General Surgery, Naples, Italy
Crohn's disease (CD) is a chronic inflammatory bowel disorder which is relapsing and remitting in nature and is characterised by transmural inflammation. About the therapeutical management of CD, it is believed to be particularly important to differentiate between active inflammation and fibrotic lesions in CD patients. Bowel sonography (BS) and MRI-enterography (MRI) are procedures widely used for diagnosing CD and its complications. Aim: to define the features of the CD strictures, also correlating BS and MRI with histopathology.
We performed an observational prospective study including all CD patients undergoing surgery for strictures. Pre-operative assessment was performed by BS and MRI. BS investigated for: bowel wall thickness (BWT), bowel wall stratification, power-Doppler vascular pattern of the bowel wall, mesentery hypertrophy and enlarged lymphnodes. MRI study included: BWT, T1-weighted gadolinium-based contrast uptake, enhancement pattern, mural and lymph node/cerebrospinal fluid (CSF) signal intensity ratios on T2-weighted fat-saturated images, mesenteric signal intensity on T2-weighted fat-saturated images. Histopathological inflammation was graded by the acute inflammatory score (AIS); the semi-quantitative degree of fibrosis was performed according to the literature. Statistical analysis was performed using chi-square, Mann–Whitney U test and Cohen's k measure.
The study included 20 CD patients. The indications to surgery were: obstructive symptoms in 13 patients, penetrating complications in 7 patients. All but 3 strictures (87%) showed acute inflammation coexisting with fibrosis while only 3 strictures were predominantly fibrotic On BS, the presence of a layered bowel wall stratification was the only variable associated with the presence of fibrosis (k=0.72; p < 0.03). About MRI, AIS correlated with mural thickness and mural/CSF signal intensity ratio on T2 sequences (p = 0.04, p = 0.02) but not with mural enhancement on T1 images (p = 0.62).
The majority of strictures in CD patients treated by surgery are consistent with a mixed type inflammation (acute inflammation plus fibrosis). The presence of stratified BS pattern shows a significantly higher degree of fibrosis while the evidence of high mural signal intensity on T2-weighted fat-saturated images on MRI reflects histological features of acute inflammation. Even if the ideal definition of the type of the strictures in CD still remains significantly far to be obtained, the combined use of BS and MRI can offer useful information in a sub-group of patients needing surgery for complicating CD.