Objective To study on the effectiveness of endoscopic ultrasonography (EUS) in diagnosing common bile duct (CBD) stones. Methods Accuracies for the diagnosis of choledocholithiasis by abdominal ultrasonography ( B-US) and computed tomography (CT) are compared with those by EUS in 45 patients. Final diagnosis is determined by endoscopic retrograde cholangiography ( ERC) with or without sphincterotomy ( EST) or operative exploration. Results Forty-three out of 45 patients with choledtx-holithia sis were diagnosed by EUS, of them 2 patients with slight dilation of common bile duct in which stones were confirmed in the proximal part of common bile duct by EST. In 2 out of 43 patients EST and operation diagnosed cholecystolithiasis instead of choledocholilhiasis. The sensitivity and the positive predictive value are both 95%. With 41 patients choledocholithiasis were confirmed by EUS, the sizes of stone were diameter ≥ 10mm in 5 patients, 6-9 mm in 10 patients and ≤5mm in 26 patients. Four out of 45 patients were suspected to have CBD stones and 2 patients had tumor in periampullar area by B-US. Three patients were diagnosed to have CBD stone and 1 patient was suspected to have tumor in peri-ampullar area by CT. Conclusions EUS appears to be the best diagnostic tool for the diagnosis of choledocholithiasis compared with other noninvasive procedures such as B-US and CT. EUS is at least as sensitive as ERC especially in diagnosis of small CBD stones.

In order to investigate the lesion' s extention and the infiltrated deepth and the metastasis of the tumors preoperatively ,endoscopic ultrasonography (EUS) was performed in 28 patients with ampullary carcinoma and 18 patients with extrahepatic bile duct carcinoma. forty six patients underwent surgical ex- plorations. A radical resection with detailed pathological study was done for 22 resectable cases of ampullary carcinoma and all the 18 cases of extrahepatic bile duct carcinoma. Carcinoma of ampulla of Vater and ex- trahepatic bile duct were assessed and staged preoperatively according to the TNM staging system. The re- sults of EUS were compared with surgical explorations and pathological findings for evaluating the accuracy of preoperative staging of EUS. The accurate rate of EUS in assessing the extent of cancer invasion was 8l.8% for ampullary carcinoma, 72. 2% for extrahepatic bile duct carcinoma. The accuracy of EUS in pre- dicting regional lymph node metastasis was 59% for ampullary carcinoma , and 61.6% for extrahepatic bile duct carcionoma. invasion of portal vein was correctly predicted by EUS in 2 out of 3 patients of ampullary carcinoma. All the 3 cases of liver metastasis were not detected by EUS. EUS is a more accurate diagnostic method in judgement of invasive extent of ampullory carcinoma and extrahepatic bile duct carcinoma preop- eratively , but less accurate for metastasis of the tumors.

30 patients with colorectal carcinoma underwent endoscopic ultrasonography(EUS)and microvessel counting for staging before operation.The accuracy of EUS in assessing depth of tumor in- filtration was 76.7%,that in detecting lymph node involvement being 73.3%.The correctness of pre- operative Duke's staging remained 70%.Microvessel counting correlated with depth infiltration and lymph node invasion.The microvascularity in tumor with serosal involvement was obviously abundant than that without,so as in tumor with and without lymphatic invasion.The results revealed that both EUS and microvessel counting can be considered as an essential evidence for preoperative staging of col- orectal cancer and thereby for predicting prognosis.

Objective To analyze the characteristics of gastric stromal tumors(GST)under endoseopic ultrasonography(EUS)according to its aggressive risks.Methods The clinical data of 36 patients with GST,who underwent surgery from July 1997 to July 2007,were analyzed retrospectively.All the patients underwent EUS before operation and were classified according to Fleether's 4-tier system to predict the aggressiveness of the tumors.The features of the tumor under EUS including its size,ulceration,border,echo charateristies and growth pattern were recorded and the difference between each tumor group were analyzed by ANOVO and rank sam test.Results The mean maximal diameter of GST Was 7.3 cm(range 1.0-20.0 cm),and the size of tumors with hiisher aggressiveness risk Was significantly larger than that with lower risk(P＜0.01).The mucosal ulceration,obscure border,irregular shape and echo heterogeneity were more commonly seen in the groups with higher risk(P＜0.05).There Was no difference in the internal echo and growth pattern of GST between different groups.Conclusion EUS features are useful in differentiation of the aggressiveness risk of the GST.and guide the management of the tumors.

Objective To determine the function and clinical significance of OMOM capsule endos-copy. Methods To review the history and outcomes of 65 patients underwent capsule endoscopy from Oct. to Dec. 2004. Results OMOM capsule endoscopy failed to pass the pylorus within the effective working time in one case. The significant pathological findings were revealed in 47 patients among 64 patients (73. 4% ). Inflammatory small bowel diseases in 21 patients including Crohn's disease in 3 patients, small intestinal pol-yps in 8 patients including one Peutz-Jeghers syndrome, angiodysplasia in 9, diverticula in 3, hookworm in 3, submucosal tumor in 3 including one myosarcoma finally diagnosed by operation. OMOM capsule endosco-pies have working time 473 min (360-630) averagely. The duration from oral to anus was 1723 min (690-2370 min) averagely. Conclusion The capsule endoscopy is a highly useful technique in detecting small in-testinal diseases. It can be recommended as part of the routine work-up in patients with obscure bleeding.

Objective To evaluate safety and efficacy of endoscopy therapy for early colorectal carcinoma of different types. Methods Clinical data of 113 patients with early colorectal carcinoma who were treated with different endoscopic therapies including polypectomy,EMR and ESD(ESD with snare and standard ESD)were retrospectively analyzed. The size, en bloc resection rate, curative resection rate, procedure time,associated complications and recurrence rate were compared among groups. Results Eleven pedunculated lesions were treated with polypectomy or EMR, which were en bloc resected and curative resected with no complication or local recurrence. Nineteen semi-pedunculated lesions were treated with EMR or ESD with no complications. Lesions treated with EMR were smaller than those of ESD(P=0.026), and had a lower en bloc resection rate[77.8%(14/18)VS 1/1,P=1.000]. The difference of curative resection rate and recurrence rate between groups was not significant(P>0.05). Eighty-three sessile lesions were treated with all three procedures.Lesions treated with ESD were larger than EMR(P=0.000),with a higher curative resection rate than EMR[95.5%(42/44)VS 77.8%(28/36),P=0.041]and a longer procedure time than EMR(P=0.000). There were no significant difference in severe complications[9.1%(4/44)VS 0],en bloc resection rates and recurrence rates(P>0.05). Ten lesions treated with ESD-S had a medium size between EMR and standard ESD group, with a significant shorter procedure time than standard ESD group(36.9 ± 24.7 min VS 120.4 ± 152.3 min, P=0.004).They were en bloc resected and complete resected. Conclusion Endoscopic treatment is safe and effective for early stage colorectal carcinoma. In order to get en bloc curative resection,endoscopists should carefully choose a suitable technique based on the macroscopic morphology of lesions. ESD-S can be used as a transitional method from EMR to ESD.

Objective To assess the efficiency and safety of endoscopic submucosal dissection (ESD)on treatment of colorectal lesions. Methods Clinical data of 163 patients with colorectal lesions, who underwent ESD at Endoscopy Center of Peking University First Hospital from June 2012 to June 2016, were retrospectively analyzed. The clinicopathologic features, the rate of en bloc resection, complete resection,complication and recurrence were reviewed. Results Among the 163 colorectal lesions,118 were mucosal lesions and 45 were submucosal ones. The mucosal lesions included 31 cases of protruding type,22 of flat type and 65 of laterally spreading tumor(LST). The submucosal lesions were all protruding type. The median lesion diameter was 2.2(2.0)cm, median operation time was 42(53)min. En bloc resection rate was 92.6%(151/163),and complete resection rate was 86.5%(141/163). The risk factor related to en bloc resection rate and complete resection rate was tumor size(P<0.05).Complications occurred in 4 cases, including 2 cases of intraoperative bleeding and 1 case of delayed bleeding who received endoscopic hemostasis therapy,and 1 patient with delayed perforation,which was managed by emergency surgery. Four recurrences were observed in 135 cases during follow-up, of which 3 were cured by additional endoscopic treatment,and 1 by surgery. Conclusion ESD is a safe and effective, but less invasive technique for colorectal lesions. Favorable long-term clinical outcomes can be achieved when en bloc curative resection is performed.

Objective To investigate the efficiency and safety of endoscopic submucosal dissection (ESD)for rectal neuroendocrine neoplasm(NEN). Methods A retrospective analysis was performed on data collected from 58 consecutive patients with rectal NEN,who underwent endoscopic ultrasonography and followed by ESD from January 2006 to January 2016 at Peking University First Hospital. Patients′endoscopic and pathological features, clinical manifestations, R0 resection rate and follow-up results were studied. Results En bloc resection was achieved for all of the 58 lesions with a mean diameter of 7.6 mm(range 3.0-18.0 mm). The complete resection rate was 94.8%(55/58). One patient showed postoperative bleeding. The diameter of lesion more than 15 mm increased the risk of non-R0 resection(P<0.05). During the mean follow-up of 3.2 years(range 1.2-11.2 years), all patients remained free from local recurrence. However,distant metastasis was detected in 1 NEN G2 patient with lymphatic invasion(1.7%). Conclusion ESD is effective for treatment of rectal NEN with diameter less than 15 mm and causes less complications. Tumor features and stage determine the risk of distant metastasis,so long-term follow-up is essential.

Objective:To evaluate the safety and efficacy of rubber band and clip facilitated endoscopic submucosal dissection (RAC-ESD) for colorectal neoplasms.Methods:A retrospective cohort study was performed. Clinical data of 115 patients with colorectal neoplasm receiving ESD from September 2018 to August 2019 were retrospectively analyzed. Thirty-four patients received RAC-ESD treatment (RAC-ESD group) and 81 received conventional ESD treatment (conventional ESD group). The procedure time, the dissected area per minute during ESD, en bloc resection rate, complete resection rate, curative resection rate, complication occurence and recurrence rate were compared between the two groups.Results:The median specimen area of RAC-ESD group was 6.32 (7.53) cm 2, and the median procedure time was 40.0 (55.0) min. The mean dissected area per minute was 0.14 (0.20) cm 2/min. While in conventional ESD group, the median specimen area was 4.71 (5.02) cm 2, the median procedure time was 50.0 (50.0) min and the mean dissected area per minute was 0.09 (0.07) cm 2/min. The median specimen area of RAC-ESD group was slightly larger and the median procedure time was slightly shorter than those of conventional ESD group, but neither was significantly different(both P>0.05). The median dissected area per minute of RAC-ESD group was significantly larger than that of the conventional ESD group ( P=0.008). The en bloc resection rate, complete resection rate and curative resection rate of RAC-ESD group were 100.0% (34/34), 100.0% (34/34) and 97.1% (33/34), while those of the conventional ESD group were 100.0%(81/81), 96.3%(78/81) and 91.4%(74/81), respectively. There was no ESD-related complication in either group. After 10.0±5.5 months of follow-up, there was no local recurrence in both groups. Conclusion:RAC-ESD may increase resection efficacy with safety.

Objective:To assess the effectiveness and safety of endoscopic submucosal dissection (ESD) in the treatment of early esophagogastric junction (EGJ) cancer and precancerous lesion.Methods:Clinical data of 67 patients with Siewert type Ⅱ early EGJ cancer or precancerous lesion who underwent ESD at Endoscopy Center of Peking University First Hospital from July 2012 to June 2019 were retrospectively analyzed. Clinical and pathological features, technical data and complication rate were reviewed. The factors that may affect the curative resection were analyzed.Results:Among the 67 cases, 5 were protruding type, 59 flat type, and 3 depressed type. The median lesion diameter was 1.6 ( QR: 1.8) cm, the median operation time was 60.0 ( QR: 56.0) min. The en bloc resection rate was 97.0% (65/67), the complete resection rate was 91.0% (61/67), and the curative resection rate was 82.1% (55/67). Factors related to non-curative resection were tumor size ( OR=8.457, 95% CI: 1.227-58.302, P=0.030) and pathological type ( OR=15.133, 95% CI: 1.518-150.870, P=0.021). ESD-related complications occurred in 3 cases (4.5%), including 1 case of delayed hemorrhage who received endoscopic hemostasis therapy, and 2 cases of post-operative cicatricial stricture who then received endoscopic dilation. Fifty-eight patients were followed up, and recurrence was found in 1 patient during follow-up with positive vertical margin who refused subsequent therapy.Metachronous early gastric cancer was found in another patient during follow-up, who was treated with a second ESD. Conclusion:ESD is a safe, effective and less invasive technique for early EGJ cancer and precancerous lesion. Tumor size, boundary and infiltration depth of the lesion should be accurately evaluated before operation to formulate appropriate treatment strategies.