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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 explore the diagnostic efficacy of nomogram based on multi-parameter MRI for assessment of bowel fibrosis in patients with Crohn disease（CD).Methods:The clinical and imaging data of CD patients diagnosed by surgical histopathology in the First Affiliated Hospital of Sun Yat-sen University from June 2015 to March 2018 were prospectively collected. All the patients underwent conventional MRI and diffusion kurtosis imaging（DKI) within 2 weeks before surgery. Patients who underwent surgery between June 2015 and September 2017 were included in the model building group, and those who underwent surgery between October 2017 and March 2018 were included in the model validation group. We measured the apparent diffusion coefficient（ADC) from monoexponential model of diffusion-weighted imaging（DWI), apparent diffusional kurtosis（K app), and apparent diffusion for non-Gaussian distribution（D app) from non-Gaussian DKI model, and observed T 2WI signal intensity and enhancement pattern of the same segment. One to three intestinal specimens per patient were stained with Masson′s trichrome for the histological grading of fibrosis. Correlations between qualitative/quantitative MRI indexes and histological grades were evaluated using the Spearman rank test. Multivariate logistic regression analysis was performed to identify independent factors to be included into the nomogram for predicting the degree of bowel fibrosis and its diagnostic performance was assessed by internal and external validation. Results:A total of 40 CD patients were included, including 31 in the model construction group and 9 in the model verification group. A total of 81 intestinal specimens from 31 patients were graded as none-to-mild bowel fibrosis（ n=32) and moderate-to-severe bowel fibrosis（ n=49) according to a scoring system of fibrosis. In the training cohort, the K app value of moderate-to-severely fibrotic bowel walls was significantly higher than that of none-to-mildly fibrotic bowel walls, and the D appand ADC values of moderate-to-severely fibrotic bowel walls were significantly lower than those of none-to-mildly fibrotic bowel walls（ Z=-5.999, -4.521 and -3.893; P<0.001). There was no significant difference in T 2WI signal intensity or enhancement pattern between these two groups（χ2=1.571 and 0.103; P>0.05). Moderate and mild correlations of histological fibrosis grades with K appand D app( r=0.721 and -0.483; P<0.001), and a mild correlation with ADC（ r=-0.445, P<0.001) were found. Independent factors derived from multivariate logistic regression analysis to predict the degree of bowel fibrosis were K app and D app. Internal and external validation revealed good performance of the nomogram with concordance index of 0.901（95% confidence interval, 0.824-0.978) and 1.000, respectively, for differentiating none-to-mild from moderate-to-severe fibrosis. Conclusion:The DKI-based nomogram can be used to evaluate the bowel fibrosis in CD patients and provides a visual and simple prediction method for clinic.
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<p><b>OBJECTIVE</b>To evaluate the diagnostic value of 3.0T high-resolution MRI in mesorectal lymph node metastasis of rectal cancer.</p><p><b>METHODS</b>The images and postoperative pathological data of patients with pathologically diagnosed rectal cancer who underwent prospective 3.0T two dimensional high-resolution MRI rectal examinations and surgery within two weeks after MRI examination at the First Affiliated Hospital, Sun Yat-sen University from November 2015 to November 2016 were retrospectively collected. Patients who received preoperative neoadjuvant therapy and those who did not undergo operation after MRI examination were excluded. The MRI sequences included high-resolution sagittal, coronal and oblique axial T2 weighted image (T2WI) (repetition time/echo time, 3000-4000 ms/77-87 ms; slice thickness/gap, 3 mm/0 mm; field of view, 18-22 cm). Two abdominal MRI radiologists independently assessed the morphology, margin, signal of all visible mesorectal nodes, measured their minor axes (three times for each radiologist) and gave estimation of the malignancy. The criteria of metastatic nodes on high-resolution MRI T2WI were nodes with irregular shape, ill-defined border and/or heterogeneous signal. The results of MRI diagnosis were compared with postoperative pathology. The sensitivity, specificity, accuracy, positive predictive value(PPV) and negative predictive value(NPV) of mesorectal nodes and nodes with different short-axis diameter ranges were calculated to evaluate the diagnostic efficiency of high-resolution MRI. Kappa statistics was used to evaluate the agreement for per node and for per patient between high-resolution MRI and pathological results. A Kappa value of 0-0.20 indicated poor agreement; 0.21-0.40 fair agreement; 0.41-0.60 moderate agreement; 0.61-0.80 good agreement; and 0.81-1.00 excellent agreement.</p><p><b>RESULTS</b>A total of 81 patients were enrolled in the retrospective cohort study, including 50 males and 31 females with age of (59.3±11.1) years. Histopathology showed 1 case of well differentiated adenocarcinoma, 63 of moderately differentiated adenocarcinoma, 9 of moderately to poorly differentiated adenocarcinoma, 2 of poorly differentiated adenocarcinoma, 3 of mucinous adenocarcinoma and 3 of tubulovillous adenocarcinoma. Histopathological staging showed 2 cases in T1 stage, 20 in T2 stage, 45 in T3 stage and 14 in T4 stage; 34 in N0 stage, 40 in N1 stage and 7 in N2 stage; 76 in M0 stage and 5 in M1 stage. A total of 377 nodes were included in the node-by-node evaluation, of which 168 (44.6%) nodes were metastatic from 58.0% (47/81) patients. The median short-axis diameter was 5.4(2.4-18.6) mm in metastatic nodes, which was significantly larger than 3.8 (2.0-8.7) mm in non-metastatic nodes[Z=10.586, P=0.000]. The sensitivity, specificity, accuracy, PPV and NPV were 74.4% (125/168), 94.7% (198/209), 85.7% (323/377), 91.9% (125/136) and 82.2% (198/241), respectively. The Kappa values between high-resolution MRI and histopathological diagnosis for node-by-node and patient-by-patient were 0.71 and 0.70 respectively, indicating good agreements. Fourteen nodes >10 mm were all metastatic. The results of high-resolution MRI for nodal status were consistent with the results of histopathological diagnosis, and the sensitivity, accuracy and PPV were all 100.0%. Among 124 nodes with short-axis diameter of 5-10 mm, 95 (76.6%) were metastatic, and the sensitivity, specificity, accuracy, PPV and NPV were 78.9% (75/95), 86.2% (25/29), 80.6% (100/124), 94.9% (75/79) and 55.6% (25/45), respectively. The agreement was fair (Kappa value 0.55) between high-resolution MRI and histopathological diagnosis. Among 239 nodes with short-axis diameter ≤5 mm, 59(24.7%) were metastatic, and the sensitivity, specificity, accuracy, PPV and NPV were 61.0% (36/59), 96.1%(173/180), 87.4%(209/239), 83.7%(36/43) and 88.3%(173/196), respectively. The agreement was good (Kappa value 0.63) between high-resolution MRI and histopathological diagnosis.</p><p><b>CONCLUSION</b>Rectal high-resolution MRI has good diagnostic value for estimating metastatic mesorectal nodes by evaluating the morphology, margin and signal of nodes.</p>
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Aged , Female , Humans , Male , Middle Aged , Lymph Nodes , Lymphatic Metastasis , Diagnostic Imaging , Magnetic Resonance Imaging , Neoplasm Staging , Prospective Studies , Rectal Neoplasms , Diagnostic Imaging , Pathology , Retrospective Studies , Sensitivity and SpecificityABSTRACT
Objective To explore the repeatability and consistency of MR intravoxel incoherent motion (IVIM) parameters of rectal cancers.Methods Routine high resolution rectal MR and IVIM sequence were performed on 128 patients with pathologically proved rectal cancers before treatment.IVIM maps were generated from two sets of b-values (group A:0,5,10,20,30,40,60,80,100,150,200,400,600 and 1000 s/mm2;group B:0,5,10,20,30,40,60,80,100,150,200,400,600,1000,1500 and 2000 s/mm2),and IVIM parameters (D,D* and f) were measured.Then IVIM parameters were measured again by the same observer three months later.The intra-class correlation coefficient (ICC) and Bland-Altman graph analysis were performed to explore the repeatability and consistency of IVIM parameters.Results The differences of IVIM parameters (D,D* and f) derived from the two sets of b-values were statistically different (all P＜0.001).ICC and 95％ confidence interval (CI) of D,D* and f was 0.968 (0.955,0.977),0.780 (0.688,0.845) and 0.957 (0.934,0.970),respectively.Bland-Altman analysis showed that the 95 ％ limits of agreement of D,D* and f was (10.8％,22.4％),(14.8％,61.9％) and (-45.3％,-10.2％),respectively.There was significant difference of D* between twice measurement by the same observer (P=0.001);ICC and 95％CI of D,D* and f was 0.826(0.670,0.908),0.678 (0.392,0.830) and 0.910 (0.830,0.952),respectively.Furthermore,Bland-Altman analysis showed that the 95％ limits of agreement of D,D* and f were (-15.3％,12.4％),(-39.6％,61.2％) and (-22.6％,22.9％),respectively.Conclusion Under the two different sets of b-values,all IVIM parameters of rectal cancers demonstrate good consistency.In addition,D and f value show good repeatability.
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Objective To study the value of dual-phase enhanced multi-slice computed tomography (MSCT)scan in combination with the reconstruction technique for distinguishing gallbladder adenomyomatosis (GBA)from gallbladder cancer.Methods We ret-rospectively reviewed the CT features (including dual-phase and reconstructed images)of 36 patients with GBA (Group A,1 6 pa-tients)or gallbladder cancer (Group B,20 patients)proved by pathology.Fisher exact test was used to compare the CT findings be-tween the two groups.Results The occurrence rates of RAS,gallbladder wall smoothing,clear gallbladder border,uniform en-hancement of serous layer and thickening of the gallbladder wall were statistically significantly different between Group A and B. When using the Rokitansky-Aschoff sinuses as a parameter for the differential diagnosis of the two groups,the diagnostic accuracy reached to 92.85%.Conclusion Dual-phase enhanced MSCT scan in combination with the reconstruction technique is a valuable ima-ging technique for distinguishing GBA from gallbladder cancer.
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AIM:To investigate the perfusion parameters using dynamic contrast-enhanced magnetic resonance imaging ( DCE-MRI) in rectal cancer patients so as to explore its potential value in estimating the microvascular condition including perfusion and permeability .METHODS:The data of 38 rectal cancer patients examined with DCE-MRI was ret-rospectively analyzed .The perfusion parameters of carcinoma and normal rectal wall in each case were calculated , inclu-ding volume transfer constant (Ktrans), rate constant of back flux (Kep), extravascular extracellular space fractional volume (Ve) and initial area under curve (iAUC).The mean values of tumor and normal rectal wall , mucinous and nonmucinous carcinoma, poorly and moderately-to-well differentiated carcinoma , case with or without lymph node metastasis were com-pared.RESULTS:All the parameters of rectal cancer were higher than normal rectal wall (P<0.01).No significant difference was found between poorly and moderately-to-well differentiated carcinoma in terms of K trans, Kep and Ve, neither was the case with or without lymph node metastasis .The cases with lymph node metastasis had lower iAUC than those with-out (P<0.05).CONCLUSION:Quantitative perfusion DCE-MRI answered the microvascular perfusion and permeability change of rectal cancer compared with normal rectal wall , besides it could be used to distinguish between mucinous and nonmucinous carcinoma , which demonstrated its value in the evaluation of rectal cancer .However , it should not be recom-mended to predict the degrees of tumor cell differentiation and lymph node metastasis just according to the perfusion param -eters.