ObjectiveTo analyze and conclude CT and MRI imaging features of ectopic pancreas in gastrointestinal tract so as to improve the understanding of the features.MethodsThe clinical, imaging, and pathological data of 12 patients with ectopic pancreas in the gastrointestinal tract confirmed by the pathology in the Sichuan Provincial People’s Hospital from November 2016 to June 2019 were retrospectively analyzed. The characteristics of image presentation were summarized.Results① The anatomical distribution: all patients had a single lesion. Of the 12 cases, 6 cases located in the gastric body lesser curvature, 3 cases located in the gastric angle, 1 case located in the posterior wall of gastric antrum, 1 case occurred in the upper jejunum, and 1 case occurred in the terminal ileum; 8 cases located in the submucosa, 2 cases located in the submucosa and muscular layer simultaneously, 1 case located in the submucosa, muscular and serous layer simultaneously, and 1 case located in the muscular layer. ② Size of the lesions: the maxium dimensions of the lesions were all 3 cm or less, and the long axes of the lesions were parallel to the gastrointestinal tract wall in 10 cases. ③ The internal characteristics: the results of 9 of 11 cases showed the isodensity compared to main pancreas on the plain CT scan. The results of 8 patients with enhanced CT showed the moderate to obvious enhancement, with 2 cases showed the slightly enhanced flaky or tube-like foci. In the arterial phase and portal venous phase, 6 cases showed the isodensity compared to main pancreas respectively. The result of MRI in 1 patient showed the isointensity compared to main pancreas on the plain scan and obviously heterogeneous enhancement.ConclusionCT and MRI could provide some information about location, size, and internal density or intensity of ectopic pancreas, and could be helpful for diagnosis.
ObjectiveTo study the value of dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) in predicting and evaluating the efficacy of neoadjuvant chemoradiotherapy (NCRT) in the middle-low locally advanced rectal cancer (LARC).MethodsThe patients were included prospectively who were clinically diagnosed as the LARC and were scheduled to undergo the NCRT and total mesorectal excision (TME) in the Sichuan Provincial People’s Hospital from February 2018 to November 2019. The routine MRI and DCE-MRI were performed before and after the NCRT, then the TME was performed. According to the score of tumor regression grade (TRG), the patients with TGR score of 0, 1 or 2 were classified as the response to NCRT group, and those with TRG score of 3 were classified as the non-response to NCRT group; in addition, the patients with TGR score of 0 or 1 were classified as the good-response group, with TRG score of 2 or 3 were classified as the poor-response group. The differences of quantitative perfusion parameters of DCE-MRI between two groups were compared, including the volume transfer constant (Ktrans), flux rate constant (Kep), and extravascular extracellular volume fraction (Ve) and the change rates of these parameters (ΔKtrans, ΔKep, and ΔVe).ResultsForty-one patients who met the inclusion criteria were included in this study, including 27 cases in the response to NCRT group and 14 cases in the non-response to NCRT group; 11 cases in the the good-response group and 30 cases in the poor-response group. ① The values of Ktrans before the NCRT and the ΔKtrans in the response to NCRT group were higher than those in the non-response to NCRT (P<0.05), while the other indexes had no significant differences between these two groups (P>0.05). The area under the receiver operating characteristic curve (AUCs) of Ktrans and ΔKtrans in predicting the efficacy of NCRT were 0.954 and 0.709, respectively. When the optimal thresholds of Ktrans and ΔKtrans were 0.122/min and –24.2%, the specificity and sensitivity were 85.7%, 96.3% and 100%, 51.7%, respectively. ② The Ktrans value in the good-response group was higher before NCRT and which was lower after NCRT as compared with the poor-response group (P<0.05). The absolute value of the the ΔKtrans and ΔKep in the good-response group were higher than those in the poor-response group (P<0.05). The other indexes had no significant differences between these two groups (P>0.05). The AUC of Ktrans before NCRT in predicting the efficacy of NCRT was 0.953. When the optimal thresholds of Ktrans before NCRT was 0.158 /min, the specificity and sensitivity were 88.7% and 90.9%, respectively. The AUC of ΔKtrans in predicting the efficacy of NCRT was higher than that of the ΔKep (0.952 versus 0.764, Z=2.063, P=0.039). When the optimal threshold of ΔKtrans was –38.8%, the specificity and sensitivity were 76.7% and 100%, respectively.ConclusionsDCE-MRI can predict and evaluate the effect of NCRT in patients with middle-low LARC, especially Ktrans and ΔKtrans (change rate before and after NCRT) have a high diagnostic efficiency.
Objective To conclude the CT manifestations and pathological features of low-grade appendiceal mucinous neoplasms. Methods We reviewed the clinical and CT findings of 24 patients with low-grade appendiceal mucinous neoplasms, who were confirmed by pathology within 1 month after CT examination in SichuanProvincial People’s Hospital from January 2018 to December 2020. The distribution, morphological characteristics, cyst wall and internal characteristics, CT value and enhancement characteristics of tumors were be detected in detail. Results ① Distribution: of the 24 patients, 22 patients located in the appendix area of the right lower quadrant, 2 patients located in the right middle abdomen, and 2 patients located in the pelvic cavity. ② Morphological characteristics: of the 24 patients, 15 patients manifested as tubular, 3 patients manifested as ellipsoidal, 5 patients manifested as saccular, and 1 patient manifested as irregular shape. The average length of tumors was about 6.4 cm (4.2–12.0 cm), and the average short diameter of tumors was about 2.2 cm (0.8–5.0 cm). The short diameter of 17 patients were more than 1.5 cm. ③ The cyst wall and internal characteristics: all the 24 patients demonstrated as cystic mass, 6 patients had evenly thin and smooth cyst wall, and other 18 patients had uneven cyst wall. Of all the patients,8 patients had arc-shaped, punctate or eggshell-like calcification. ④ The CT value and enhancement characteristics: 24 patients examined by plain CT scan, 22 patients showed uniform low density (the CT value were 7–25 HU), 2 patients contained some slightly high density, 16 patients examined by enhanced CT, the cyst wall, separation, or mural nodules of 8 patients were slightly or moderately enhanced. ⑤ Pathological results: of all the gross specimens, 15 patients showed tubular dilation, 9 patients showed partial or complete dilation as cystic mass. All the 24 patients had gelatinous or mucinous contents. Microscopically, all the patients showed low-grade mucinous epithelial hyperplasia, submucosa, and mucosal muscle atrophy, accompanied by fibrosis or calcification. Conclusion Low-grade appendiceal mucinous neoplasms show some specific CT manifestations, recognize these features can improve the accuracy of preoperative CT.