ABSTRACT
Objective:To develop a mesenteric creeping fat index (MCFI) based on CT enterography (CTE) to characterize the degree of creeping fat wrapping around the inflamed gut in Crohn disease (CD), and to assess the relationship between MCFI and the inflammatory intestinal stricture.Methods:From December 2018 to July 2019, the patients with CD who underwent surgery in the First Affiliated Hospital of Sun Yat-Sen University were prospectively collected. The extent of perienteric mesenteric vessels wrapping around the gut was reconstructed to develop MCFI based on CTE images. The intestinal stricture index was obtained by calculating the ratio of the maximal upstream luminal diameter divided by the minimum luminal diameter apparent within the stricturing region. Using region-by-region correlation between CTE and surgical specimen, creeping fat score in intestinal specimen was obtained by assessing the extent of creeping fat wrapping around the resected bowel segment, and HE staining was performed on the bowel specimen corresponding to creeping fat to obtain the pathological inflammatory score. The Spearman correlation analysis was used to evaluate the correlation between MCFI, creeping fat score in intestinal specimen, and inflammatory score, intestinal stricture index. The ROC curve analysis was used to assess the accuracy of MCFI in distinguishing moderate-severe and mild inflammatory bowel walls.Results:Totally 30 CD patients were enrolled. The creeping fat score in intestinal specimen positively correlated with pathological inflammatory score ( r s=0.403, P=0.027) and with intestinal stricture index ( r s=0.642, P<0.001). MCFI positively correlated with creeping fat score in intestinal specimen ( r s=0.840, P<0.001), with pathological inflammatory score ( r s=0.497, P=0.005), and with intestinal stricture index ( r s=0.599, P<0.001). ROC analysis showed that the area under the curve of MCFI for differentiating moderate-severely from mildly inflammatory bowel walls was 0.718 (95%CI 0.522-0.913). Using MCFI≥4 as a cutoff value, the sensitivity and specificity were 81.8% and 47.4%, respectively. Conclusions:There was a correlation between creeping fat and inflammatory intestinal strictures in CD. MCFI can non-invasively depict the degree of creeping fat wrapping around the gut and assess the inflammatory intestinal stricture.
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Objective To assess the diagnostic value of magnetization transfer MRI (MTI) for bowel inflammation and fibrosis in humans with Crohn disease (CD). Methods From July 2014 through April 2017, 31 patients with a confirmed diagnosis of CD were prospectively recruited from the First Affiliated Hospital of Sun Yat Sen University. They were scheduled for elective surgery due to bowel obstruction and other complications, and underwent preoperative MR enterography (MRE) and MTI within 15 days of surgery. All cases had available intestinal specimens identified on MRE and resected bowel segments for region by region matching. All patients underwent breath hold conventional MRE and MTI examinations, and then the magnetization transfer ratios (MTRs) of pathological bowel segments were measured. Using region by region correlation between MTI and surgical specimen, the bowel segments were resected to stain with HE for evaluating bowel inflammation, Masson for bowel fibrosis, and typeⅠcollagen staining for the deposition of typeⅠcollagen within the bowel walls. The histologic sections from the most severe areas were scored as 0 (normal), 1 (mild), 2 (moderate) and 3 (severe). The correlations between MTR and histologic scores were analyzed by using Spearman rank correlation or partial correlation. The differences in MTR among different grades of bowel fibrosis were analyzed by one way ANOVA. The efficacy of MTR for predicting bowel fibrosis was evaluated by receiver operating characteristic curves analysis. The difference in MTRs between purely inflammatory bowel walls and mixed fibrotic and inflammatory bowel walls was analyzed by Student s t test. Results Sixty two resected bowel specimens from 31 patients including 9 purely inflammatory bowel walls and 53 mixed fibrotic and inflammatory bowel walls were obtained in this study. There were significant differences in MTR among non fibrotic [(21.45 ± 2.65)%], mildly [(30.88 ± 6.14)%], moderately [(35.14 ± 4.31)%] and severely [(35.14 ± 4.31)%] fibrotic walls (F=38.397,P<0.01). MTRs strongly correlated with fibrosis scores (r=0.681, P<0.01). High accuracy of MTRs was shown (curve under area=0.905, P<0.01) for differentiating moderately severely fibrotic from non fibrotic and mildly fibrotic bowel walls. Using MTR of 31.50% as a cutoff value, the sensitivity and specificity were 93.6% and 80.0%, respectively. The MTRs of purely inflammatory bowel walls [(21.45 ± 2.65)%] were significantly higher than that of mixed fibrotic and inflammatory [(36.28±5.21)%] bowel walls (t=-13.052,P<0.01). MTRs correlated with the scores of type Ⅰ collagen (r=0.325, P=0.044) but did not correlate with inflammation scores (r=-0.024, P=0.857). Conclusions MTI enables quantitative evaluation of bowel fibrosis in patients with CD and can be used to differentiate purely inflammatory CD from mixed fibrotic and inflammatory CD.
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[Objective] To analyze the image findings of MR enterography (MRE) and diffusion weighted imaging (DWI) in Crohn disease (CD) and to discuss the diagnostic value of MRI for evaluating the activity of CD.[Methods] 26 patients proved by clinical,imaging and pathological data were enrolled in this study.The intra-/extra-intestinal image features of CD were retrospectively analyzed,and the intestinal lesions were evaluated by MRE+DWI scoring system.The differences in image features of active and inactive CD were compared.[Results] 26 bowel segments were evaluated and included active (n =20) and inactive CD (n =6).The intestinal performance of CD included wall thickening,T2WI hyperintensity and hyperenhancement.The pathological changes of active CD were more serious when comparing with that of inactive CD.DWI showed hyperintensity in the affected bowel wall.ADC of active C D [(0.9 ± 0.2) × 10-3 mm2/s] was significantly lower than that of inactive CD [(1.5 ± 0.4)× 10-3 mm2/s] (P ＜ 0.001).Extra-enteric performance of active CD included comb sign,lymphadenectasis of mesentery,mesenteric exudation,fistula and abdominal abscess.[Conclusion] MRE combined with DWI can accurately assess CD activity and diagnose extra-enteric complications.
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Objective To explore the diagnostic value of magnetization transfer imaging (MTI) and DWI for detecting intestinal wall property of crohn's disease (CD). Methods Forty four patients with CD were prospectively enrolled in the study, and MR enterography (MRE), MTI and DWI were performed. According to MRE findings, patients were divided into three subgroups:acute inflammatory group, chronic fibrotic group and combined inflammatory with fibrotic group. Intestinal wall T2WI signal, magnetization transmisson rate (MTR) and ADC value were measured on MRE, MRI and DWI imagings, respectively. The differences of MTR and ADC among the three groups were analyzed by one-way ANOVA;the differences of T2WI scores were analysed by Kruskal Wallis;the differences of MTR and ADC values between normal and pathological intestinal wall were analyzed by paired t test;ROC curve were used to evaluate the CD fibrosis and inflammation diagnostic efficiency of MTI ana DWI based on MRE signs. Results Among the 44 cases, 11 cases were in the acute inflammatory group, 18 cases were in the chronic fibrotic group and other 15 cases were in the combination group. The T2WI score, MTR and ADC among the three groups showed significant differences (all P<0.01).The mean MTR and ADC of pathological intestinal wall of the 44 cases were (40.77±6.05)%and (1.04±0.18)× 10-3mm2/s, and the adjacent normal bowel were (21.75±4.17)%and (1.97 ± 0.23) × 10- 3mm2/s, respectively. Moreover, the difference of the above values showed significant differences (t=19.12,-21.80 respectively, all P<0.01). There was a negative correlation between MTR and T2WI score (r=-0.71,P<0.01). While ADC value was positively correlated with T2WI score (r=0.80, P<0.01). Using ROC curve analysis to differentiate the CD fibrosis from acute inflammation, the area under the curve (AUC) of MTR and ADC were 0.97 and 0.96 ,respectively. Conclusions Both MTI and DWI can be used to assess the properties of intestinal wall, which has the same diagnostic efficacy to identify the acute inflammation and fibrosis.