Objective To evaluate the value of diffusion-weighted imaging (DWI) in the differential diagnosis of cystic pancreatic lesions.Methods Thirty-four cystic pancreatic lesions confirmed clinically or pathologically were collected,including 11 case of non-neoplastic pseudocyst,5 cases of simple cyst,6 cases of serous cystadenoma,10 cases of mucinous cystadenoma and 2 cases of mucinous cystadenocarcinoma.All the patients underwent routine serial MR and echo-planar DW imaging examination of the pancreas with b values of 0 and 600 s/mm2.The appearances of signal intensity of DWI with all cysts were recorded.ADC maps were reconstructed,and the ratio of the cysts and cyst-to-pancreas ADC (ADCR) were calculated.The receiver operating characteristic (ROC) curves were constructed to evaluate the diagnostic value of ADC and ADCR.Results Among all the 16 non-neoplastic cysts,2 cysts were slightly hyperintense in DWI,and 14 cysts were isointense.Among all the 18 neoplastic cysts,17 cysts appeared slightly hyperintense or hyperintense in DWI,and 1 cyst was isointense.The difference between the two groups was statistically significant (P ＜ 0.001).The ADC values of non-neoplastic and neoplastic cysts were (3.30 ± 0.30) × 10-3,(2.74 ± 0.34) × 10-3 mm2/s ; and the ADCR values of non-neoplastic and neoplastic cysts were 1.85 ± 0.20,1.31 ± 0.21,the difference between the two groups was statistically significant (P ＜ 0.001).The areas under the ROC curves of ADC and ADCR diagnosing neoplastic cysts were 0.94 ± 0.04,0.98 ± 0.02,respectively.An ADC of 3.105 × 10-3 mm2/s showed 81.3％ sensitivity and 94.4％ specificity for predicting neoplastic cysts.An ADCR of 1.525 showed 100％ sensitivity and 88.9％ specificity for predicting neoplastic cysts.Conclusions Diffusion-weighted imaging is of importance in the diagnosis and differential diagnosis of pancreatic cysts,and can be applied as a complementary tool for routine MRI.

Objective To evaluate the clinical value of endoscopic submucosal tunnel dissection ( ESTD) for treatment of large gastric angle superficial neoplasms. Methods A retrospective analysis was performed on data of 87 patients with superfical neoplasms in gastric angle, including 32 cases undergoing ESTD and 55 cases undergoing endoscopic submucosal dissection ( ESD) in 6 institutions between July 2014 and July 2016. The dissection time, dissection speed, en bloc resection rate, curative resection rate, adverse events, and prognosis were compared between the two groups. Results The ESTD group showed a shorter dissection time ( 87. 3 ± 32. 6 min VS 136. 7 ± 64. 5 min, P<0. 01 ) , a higher dissection speed ( 0. 18 ± 0. 07 cm2/min VS 0. 08±0. 05 cm2/min, P<0. 01), a higher en bloc resection rate[100％ (32/32) VS 87. 3％ (48/55), P=0. 035], and a higher curative resection rate[100％ (32/32) VS 85. 5％ (47/55), P=0. 024] compared with the ESD group. The intraoperative bleeding rate[59. 4％ (19/32) VS 100. 0％( 55/55) , P<0. 01] and muscular injury rate[ 0 ( 0/32) VS 14. 5％ ( 8/55) , P=0. 024] were lower in the ESTD group than those of the ESD group. There was no statistical difference on recurrence rate between the two groups[0 (0/32) VS 1. 9％ (1/54), P=0. 443]. Conclusion ESTD has a higher dissection speed and greater security on treatment of large gastric angle superficial neoplasms, and is worthy to be generalized.

Objective:To study the clinical characteristics and classification of gastric neuroendocrine neoplasm(NEN) and prognostic factors of mixed adenoneuroendocrine carcinoma (MANEC) and gastric neuroendocrine carcinoma(NEC).Methods:A total of 148 gastric NENs were divided into type Ⅰ, type Ⅱ and type Ⅲ based on the classification of European Neuroendocrine Tumor Society (ENETS). Kaplan-Meier test and Cox regression model were used in univariate and multivariate survival analysis in 108 cases with pathological G3 gastric NEN.Results:In this study, the percentages of type Ⅰ, type Ⅱ and type Ⅲ were 25.0%(37), 3.4%(5) and 71.6%(106) respectively. Among type Ⅰ patients, 28(75.7%) lesions were located in gastric fundus or body, 29(78.4%) had bumps. Lymph node involvement was found in 4 (10.8%) patients. Twenty-six (70.3%) patients received endoscopic treatment and 11 (29.7%) with surgery. All 5 type Ⅱ patients presented lesions in gastric fundus or body, including 4 with ulcers, who were all treated by endoscope. Three type Ⅱ patients had gastrinoma, and 2 combined with multiple endocrine neoplasmⅠ. In type Ⅲ patients, 56(52.8%) showed ulcerative lesions. The majority of patients (102, 96.2%) had a single lesion, 94(88.7%) with lymph node or other organ metastasis. In this study, no deaths were reported in gastric NEN with a pathological grade of G1 or G2. The mortality rate was 38.9%(42/108) in patients with G3 NEN. Survival analysis suggested that age, metastasis of tumor were associated with poor prognosis ( P=0.041, 0.025). Conclusions:Patients with gastric NEN have heterogenous clinical presentations according to gender, age, endoscopic features, infiltration and metastasis, and pathological grade. Aging and metastasis are negative prognostic factors of G3 gastric NEN.