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Background and Aims Emerging evidence points to a link between creeping fat and the pathogenesis of Crohn’s disease [CD]. Non-invasive assessment of the severity of creeping fat on cross-sectional imaging modality has seldom been investigated. This study aimed to develop and characterize a novel mesenteric creeping fat index [MCFI] based on computed tomography [CT] in CD patients. Methods MCFI was developed based on vascular findings on CT in a retrospective cohort [n = 91] and validated in a prospective cohort [n = 30]. The severity of creeping fat was graded based on the extent to which mesenteric fat extended around the intestinal circumference using the vessels in the fat as a marker. The accuracy of MCFI was assessed by comparing it with the degree of creeping fat observed in surgical specimens. The relationship between MCFI and fibrostenosis was characterized by determining if these correlated. The accuracy of MCFI was compared with other radiographic indices [i.e. visceral to subcutaneous fat area ratio and fibrofatty proliferation score]. Results In the retrospective cohort, MCFI had moderate accuracy in differentiating moderate–severe from mild fibrostenosis (area under the receiver operating characteristic [ROC] curve [AUC] = 0.799; p = 0.000). ROC analysis in the retrospective cohort identified a threshold MCFI of > 3 which accurately differentiated fibrostenosis severity in the prospective cohort [AUC = 0.756; p = 0.018]. An excellent correlation was shown between MCFI and the extent of fat wrapping in specimens in the prospective cohort [r = 0.840, p = 0.000]. Neither visceral to subcutaneous fat area ratio nor fibrofatty proliferation score correlated well with the degree of intestinal fibrosis. Conclusions MCFI can accurately characterize the extent of mesenteric fat wrapping in surgical specimens. It may become another non-invasive measure of CD fibrostenosis.

Accurate evaluation of bowel fibrosis in patients with Crohn's disease (CD) remains challenging. Computed tomography enterography (CTE)-based radiomics enables the assessment of bowel fibrosis; however, it has some deficiencies. We aimed to develop and validate a CTE-based deep learning model (DLM) for characterizing bowel fibrosis more efficiently.We enrolled 312 bowel segments of 235 CD patients (median age, 33 years old) from three hospitals in this retrospective study. A training cohort and test cohort 1 were recruited from center 1, while test cohort 2 from centers 2 and 3. All patients performed CTE within 3 months before surgery. The histological fibrosis was semi-quantitatively assessed. A DLM was constructed in the training cohort based on a 3D deep convolutional neural network with 10-fold cross-validation, and external independent validation was conducted on the test cohorts. The radiomics model (RM) was developed with 4 selected radiomics features extracted from CTE images by using logistic regression. The evaluation of CTE images was performed by two radiologists. DeLong's test and a non-inferiority test were used to compare the models' performance.DLM distinguished none-mild from moderate-severe bowel fibrosis with an area under the receiver operator characteristic curve (AUC) of 0.828 in the training cohort and 0.811, 0.808, and 0.839 in the total test cohort, test cohorts 1 and 2, respectively. In the total test cohort, DLM achieved better performance than two radiologists (*1 AUC = 0.579, *2 AUC = 0.646; both p0.05) and was not inferior to RM (AUC = 0.813, p0.05). The total processing time for DLM was much shorter than that of RM (p0.001).DLM is better than radiologists in diagnosing intestinal fibrosis on CTE in patients with CD and not inferior to RM; furthermore, it is more time-saving compared to RM.• Question Could computed tomography enterography (CTE)-based deep learning model (DLM) accurately distinguish intestinal fibrosis severity in patients with Crohn's disease (CD)? • Findings In this cross-sectional study that included 235 patients with CD, DLM achieved better performance than that of two radiologists' interpretation and was not inferior to RM with significant differences and much shorter processing time. • Meaning This DLM may accurately distinguish the degree of intestinal fibrosis in patients with CD and guide gastroenterologists to formulate individualized treatment strategies for those with bowel strictures.

In this study, we investigated the utility of native T1 mapping in differentiating between various grades of fibrosis and compared its diagnostic accuracy to magnetization transfer imaging (MTI) in a rat model of CD. Bowel specimens (64) from 46 CD model rats undergoing native T1 mapping and MTI were enrolled. The longitudinal relaxation time (T1 value) and normalized magnetization transfer ratio (MTR) were compared between none-to-mild and moderate-to-severe fibrotic bowel walls confirmed by pathological assessments. The results showed that the correlation between the T1 value and fibrosis (r = 0.438, p &lt, 0.001) was lower than that between the normalized MTR and fibrosis (r = 0.623, p &lt, 0.001). Overall, the T1 values (t = −3.066, p = 0.004) and normalized MTRs (z = 0.081, p &lt, 0.001) in none-to-mild fibrotic bowel walls were lower than those in moderate-to-severe fibrotic bowel walls. The area under the curve (AUC) of the T1 value (AUC = 0.716, p = 0.004) was significantly lower than that of the normalized MTR (AUC = 0.881, p &lt, 0.001) in differentiating moderate-to-severe fibrosis from none-to-mild fibrosis (z = −2.037, p = 0.042). Our results support the view that the T1 value could be a promising imaging biomarker in grading the fibrosis severity of CD. However, the diagnostic performance of native T1 mapping was not superior to MTI.

BACKGROUND & AIMS: No reliable method for evaluating intestinal fibrosis in Crohn’s disease (CD) exists; therefore, we developed a computed-tomography enterography (CTE)–based radiomic model (RM) for characterizing intestinal fibrosis in CD. METHODS: This retrospective multicenter study included 167 CD patients with 212 bowel lesions (training, 98 lesions; test, 114 lesions) who underwent preoperative CTE and bowel resection at 1 of the 3 tertiary referral centers from January 2014 through June 2020. Bowel fibrosis was histologically classified as none–mild or moderate–severe. In the training cohort, 1454 radiomic features were extracted from venous-phase CTE and a machine learning–based RM was developed based on the reproducible features using logistic regression. The RM was validated in an independent external test cohort recruited from 3 centers. The diagnostic performance of RM was compared with 2 radiologists’ visual interpretation of CTE using receiver operating characteristic (ROC) curve analysis. RESULTS: In the training cohort, the area under the ROC curve (AUC) of RM for distinguishing moderate–severe from none–intestinal fibrosis was 0.888 (95% confidence interval [CI], 0.818–0.957). In the test cohort, the RM showed robust performance across 3 centers with an AUC of 0.816 (95% CI, 0.706–0.926), 0.724 (95% CI, 0.526–0.923), and 0.750 (95% CI, 0.560–0.940), respectively. Moreover, the RM was more accurate than visual interpretations by either radiologist (radiologist 1, AUC = 0.554; radiologist 2, AUC = 0.598; both, P < .001) in the test cohort. Decision curve analysis showed that the RM provided a better net benefit to predicting intestinal fibrosis than the radiologists. CONCLUSIONS: A CTE-based RM allows for accurate characterization of intestinal fibrosis in CD.

The aim of the study was to compare the hemodynamic effects of endoluminal and open surgical treatment of chronic Leriche syndrome using arterial collaterals on CTA as a surrogate parameter. This retrospective, single-center study included 30 patients with chronic Leriche syndrome. Fourteen patients underwent intraluminal stent implantation (endo group), and sixteen underwent surgical bypass grafting (surgical group). CTA was performed pre- and postoperatively, and a series of evaluation parameters (a1: sum of area of the systemic collateral pathways in the abdominal wall before operation, a2: sum of area of the systemic collateral pathways in the abdominal wall after operation, ar: area of lumen of the stent or artificial vessel, BSR: post- and preoperative blood supply ratio = (a2 + ar)/a1, RR: reduction rate of systemic collateral arteries after the operation = (a1−a2)/a1) were defined to quantitatively evaluate the hemodynamic effects of the treatments. Short-term clinical outcomes, including improvement of symptoms, postoperative complications and in-hospital stay, were also collected. Then, the effects of the two operations were compared. There was no significant difference in the baseline (a1, p = 0.301) and postoperative (a2, p = 0.802) collateral arteries, as well as BSR (p = 0.088) and RR (p = 0.592) between endo and surgical groups. There was also no significant difference in short-term clinical outcomes between the two groups. Our limited series suggests that intraluminal stent implantation may not be inferior to surgical bypass grafting regarding the undifferentiated short-term clinical outcomes as well as the chosen hemodynamic surrogate parameters.

Objective To establish a novel standardized magnetization transfer ratio (MTR) parameter which considers the element of the normal bowel wall and to compare the efficacy of the MTR, normalized MTR, and standardized MTR in evaluating intestinal fibrosis in Crohn's disease (CD). Materials and Methods Abdominal magnetization transfer imaging from 20 consecutive CD patients were analyzed before performing elective operations. MTR parameters were calculated by delineating regions of interest in specified segments on MTR maps. Specimens with pathologically confirmed bowel fibrosis were classified into one of four severity grades. The correlation between MTR parameters and fibrosis score was tested by Spearman's rank correlation. Differences in MTR, normalized MTR, and standardized MTR across diverse histologic fibrosis scores were analyzed using the independent sample t test or the Mann-Whitney U test. The area under the receiver operating characteristic curve (AUC) was computed to test the efficacies of the MTR parameters in differentiating severe intestinal fibrosis from mild-to-moderate fibrosis. Results Normalized (r = 0.700; p < 0.001) and standardized MTR (r = 0.695; p < 0.001) showed a strong correlation with bowel fibrosis scores, followed by MTR (r = 0.590; p < 0.001). Significant differences in MTR (t = −4.470; p < 0.001), normalized MTR (Z = −5.003; p < 0.001), and standardized MTR (Z = −5.133; p < 0.001) were found between mild-to-moderate and severe bowel fibrosis. Standardized MTR (AUC = 0.895; p < 0.001) had the highest accuracy in differentiating severe bowel fibrosis from mild-to-moderate bowel wall fibrosis, followed by normalized MTR (AUC = 0.885; p < 0.001) and MTR (AUC = 0.798; p < 0.001). Conclusion Standardized MTR is slightly superior to MTR and normalized MTR and therefore may be an optimal parameter for evaluating the severity of intestinal fibrosis in CD.

During a rare accident involving severe core damage in a nuclear power plant, if the molten core material can be contained within the boundary of the reactor vessel, the severity of the accident is expected to be greatly reduced. Therefore, the severe accident management strategy based on in-vessel retention (IVR) of molten core debris is highly desirable, and has been adopted by advanced reactor designs such as AP1000, APR1400 and CAP1400. Previous studies assumed a fully developed molten pool, where molten metal and molten oxides separated, and liquid metal form a layer on the top of the oxidic pool. The limiting failure mechanism of the lower head is related to occurrence of boiling crisis on the outer surface of the vessel. The boiling crisis would occur, when the local heat flux through the vessel wall exceeds the critical heat flux value. The evaluation of thermal regime is then done by comparing the heat flux distribution from the molten corium pool and the CHF variation on the outer wall in order to define the available margins to CHF. When a larger power nuclear reactor is designed, the margin of the IVR could be decreased. Therefore, the study on critical heat flux enhancement for lager nuclear reactor is necessary. In this study, an experimental facility is conducted to analysis the critical heat flux mechanism and enhancement for lager power nuclear reactor. The facility includes two loops, one is primary loop, and the other is auxiliary loop which could import injection flow in the primary loop. The test section is an inclined downward heated rectangular channel, and the angle is variable. A series of critical heat flux experiments are conducted in this facility. The results are compared with previous experiment results and calculation correlation in the large nuclear reactor operating conditions.

Cryptococcus neoformans and Candida are common opportunistic pathogens of human. There is very limited literature on Cryptococcus neoformans cholangitis or Candida cholangitis in immunocompetent patient while mixed Cryptococcus neoformans and Candida cholangitis has not been reported in the literature ever before. We hereby report the imaging findings of a case of mixed Cryptococcus neoformans and Candida cholangitis in an immunocompetent boy. The CT features included nodules in the cystic duct and common bile duct, dilatation of the intra- and extrahepatic bile ducts with mural thickening, irregular hypodense mass-like lesion extending along the bile ducts from the liver hilum to the periphery which was confirmed by the presence of enlarged and confluent lymph nodes. CT characteristics can contribute to timely diagnosis and treatment of this disease.

To assess the value of MDCT with vessel probe(VP) in the diagnosis and treatment of isolated superior mesenteric artery dissection (ISMAD).Clinical and imaging data of 15 patients with ISMAD admitted to the First Affiliated Hospital of Sun Yat-Sen University from June 2008 to May 2013 were retrospectively reviewed. Relationship among radiograpic features, clinical symptoms and therapeutic options of ISMAD was examined based on the imaging of 64-MDCT with VP.The dissection crevasse of all the 15 patients located in anterior arterial wall, and the distance was(24.3±9.7) mm from the origin of SMA. Meanwhile dissection crevasse of 73.3%(11/15) patients located in the zone within 1 cm of proximal end and 1 cm of distal end of the proximal SMA curvature. There were significant differences between patients without abdominal pain(8 cases) and those with abdominal pain(7 cases) in dissection length, minor diameter ratio of true lumen to false lumen, major diameter ratio of true lumen to false lumen(all P0.01). According to classification of Yun, there were 5 patients of typeI( and 3 type II(a, whose conservative treatment were successful. In other 7 patients of type II(b, 3 patients received successful conservative treatment, and 4 patients had symptom remission after turning to interventional treatment or surgery.64-MDCT with VP can clearly depict the image manifestation of ISMAD, which provides evidence for the diagnosis and therapeutic options of ISMAD.

To explore the value of comprehensive application of CT and PET/CT in differential diagnosing mucinous and non-mucinous colorectal adenocarcinoma.CT and PET/CT image data of 37 patients with mucinous adenocarcinoma and 50 patients with non-mucinous adenocarcinoma confirmed by pathology in our hospital from January 2010 to December 2012 were analyzed retrospectively. Differences of image were compared between two methods.On CT, lesion density of pre-contrast, pro-contrast phase and enhancement degree were significantly lower in mucinous adenocarcinoma than those in non-mucinous adenocarcinoma(all P0.01). Enhancement degree of hypointense area, hypointense area proportion of total lesion, and lymphatic or distant metastasis ratio were significantly higher in mucinous adenocarcinoma than those in non-mucinous adenocarcinoma(all P0.05). On PET/CT, maximal SUV value of mucinous adenocarcinoma was significantly lower as compared to non-mucinous adenocarcinoma[(8.64±4.34) Bq/L vs. (12.38±5.96) Bq/L, P=0.015].CT combined with PET/CT provides better valuable information in differential diagnosing between mucinous and non-mucinous colorectal adenocarcinoma and clinical practice.

Partial loss of reactor coolant flow is one of the most important transients for safety analysis of supercritical water-cooled reactor (SCWR). Taking the super LWR concept provided by Japan as research object, transient analysis of partial loss of coolant flow rate is given by coupled neutronics and thermal hydraulics calculation method. The results show that, when 5% partial loss of coolant flow is happening, maximum cladding temperature would increase firstly with the decreasing of fuel channel inlet coolant flow. Then followed with the neutronic feedback and control operation, maximum cladding temperature decreases and finally return to normal. When 50% partial loss of coolant flow is happening, a scram signal will be given to ensure system safety, but the maximum cladding temperature still shows a significant increase early. On this basis, sensitivity analysis is performed considering the influence of core power and main coolant flow. It is found that maximum peaking value increases significantly following the initial flow rate decreasing, but shows a very little increase caused by core power increasing.

In comparison with the left and right hepatic arteries, there is a relative lack of information on the middle hepatic artery (MHA). In this study, data obtained by multidetector computed tomography from 145 patients were studied to evaluate anatomical variations of the MHA, a hilar artery that primarily supplies hepatic segment 4. An MHA was present in 103 (71%) of the subjects. In livers that had a replaced left hepatic artery, the MHA originated from the right hepatic artery; in livers that had a replaced right hepatic artery, it originated from the left hepatic artery. It always arose directly or indirectly from the common hepatic artery, from which the gastroduodenal artery also arose. We classified MHAs into 5 types according to the anatomical variations of the origin. This classification may have major relevance to modern surgical practice related to living donor liver transplantation (LDLT). The new classification of hepatic arterial anatomy may enhance the acquisition of further knowledge on arterial development, and its application may favorably influence the outcome of LDLT. Liver Transpl 16:736-741, 2010. © 2010 AASLD.

Physical characteristics of the coolant in the Supercritical-pressure Light Water Cooled Reactor (SCWR) vary greatly near the pseudo-critical point, which will cause variations of core neutron cross section and then bring about power perturbation. Further it will prompt the corresponding thermal parameters of supercritical water changed, and form feedback action, finally resulting in intensely coupled thermal-hydraulics and neutron-physical. Proper fuel assembly has been selected as research object, and the model of multiple parallel channels has been established. In view of this model, using DRAGON code for neutron-physical calculations and developing corresponding thermal-hydraulic programs, and then achieve coupling them through appropriate data interface, the calculation platform established. Finally the power distribution and the corresponding parameters temperature distributions in the model have been predicted. On account of deficiencies reflected in calculations, such as the heterogeneous power distribution, fuel assembly geometry has been changed, for instance the proper peripheral moderator wall has been added based on the preceding assembly, then do the coupling calculations and analyze the results. Comparisons between different results have been made, and the expected aim has been reached, which can prove the rationality of assembly modifications and meanwhile prove the usability of the calculation platform. Thus, modified assembly and the calculation platform could be the calculation foundation in future designs of SCWR.Copyright © 2010 by ASME