Objective To investigate the effects of different energy,frequency and time of holmium laser on the ablated porcine pancreas in vitro,and to establish an ablation regression equation of holmium laser,in order to provide the experiment foundation for EUS-guided holmium laser ablation of pancreatic carcinoma.Methods According to pilot study,the range of energy,frequency and time of holmium laser was determined,and five values were chosen for the individual three parameters,therefore,a randomize table including 125 combinations (sample capacity) according to the various combinations of every parameter was constructed,then every combination of holmium laser was used for porcine pancreas ablation in vitro.EUS was applied to determine the ablation site and measure the ablation extent,and pathological evaluation was performed.Results Sonographic images showed hyperechoic cloudy area in the ablation site.It was observed that the ablation body was an approximately oval area,the middle part was carbonized area,and the out layer was grey-white necrosis area.Microscopic examination showed there was pool-like cavity in the middle of ablation site,and it was surrounded by coagulation necrosis of pancreatic tissue,and the out layer was inflammatory cells infiltration.Normal pancreatic tissue was found in the margin.The energy,frequency and time of hoimium laser were positively associated with the ablation extent,and the frequency was the main factor,followed by time and energy.The difference was statistically significant (P＜O.O1).The best combination was 25 s,25 Hz,1.8 J.An ablation regression equation was created,which was In (ablation volume) =β0 + β1 × time + β2 × frequency + β3 × energy.Conclusions The holmium laser can produce obvious tissue necrosis in porcine pancreas in vitro; the established holmium laser ablation regression equation can be the guidance for clinical practice.

Objective To investigate the extent of radiofrequency ablation of pig pancreas in vitro with various power and duration,and to establish the regression equation of radiofrequency ablation of porcine pancreas in vitro.Methods Among the 4 settings of power (from 5 w ～ 20 w) and 11 settings of duration (from 40s ～ 240s),44 combinations were selected,and every combination was performed twice,then a randomization table including 88 combinations was established,and 88 ablation procedures on porcine pancreases in vitro were performed.The uhrasonography changes were observed,ablation widths (Y) were measured,and pathological examination was performed.In order to construct optimal model and to establish the regression equation of radiofrequency ablation,9 parameters (duration,power,duration × power,the square of duration,the square of power,the square root of duration,the square root of power,the natural logarithm of duration,the natural logarithm of power) derived from duration and power were analyzed via stepwise regression method.Results A rectangular echo enhanced region was observed along the working area of catheter when radiofrequency ablation started,and it gradually became wider during ablation.A hoar-like cylindrical ablation region that was clearly different from surrounding normal pancreatic tissue was formed.Carbonation of necrotic tissue could be observed after radiofrequency ablation under 15 w or 20 w.The optimal model showed a linear positive correlation between ablation width (Y) with the square of power and the natural logarithm of duration.The coefficient of determination of this model was 0.71.Both Fitting curve and Residual scatter diagram showed good fitting effect.Finally,a significant regression equation of radiofrequency ablation was established:Y (mm) =0.005 × E2 + 0.9374 × ln (t)-0.6943.Conclusions A significant regression equation of radiofrequency ablation is established,which provides experimental base for EUS-guided radiofrequency ablation of pancreatic tumors in clinical practice.

Objective To evaluate the safety and efficacy of direct celiac ganglion irradiation with 125I seeds for pain relief secondary to advanced pancreatic carcinoma (PC).Methods This study enrolled 23 consecutive patients who had moderate to severe pain resulting from advanced PC.All patients underwent EUS-guided direct celiac ganglion irradiation with 125I seeds.Follow-up was conducted at least once weekly until death.Blood parameters,Visual Analog Scale (VAS) score,mean analgesic consumption,and complications were evaluated during follow-up.Results All patients successfully underwent implantation at one attempt.The mean number of seeds implanted in the celiac ganglion per patient was 4 (range 2-6).Immediately after the procedure,pain relief and analgesic consumption showed no significant changes compared with preoperative values.Six patients (26％) reported pain exacerbation.Two weeks later,the VAS score and mean analgesic consumption were significantly less than preoperative values.No procedure-related deaths or major complications occurred.Conclusion EUS-guided direct celiac ganglion irradiation with 125I seeds can reduce the VAS score and analgesic drug consumption in patients with unresectable PC.

Objective To investigate and determine the apparent diffusion coefficient (ADC) values in different anatomical regions of normal pancreas.Methods A total of 383 volunteers with normal pancreas were included in this study.Single-shot echo planar imaging diffusion weighted imaging (SSEP-DWI; b value =0,500 s/mm2) was employed to determine the ADCs in the head,neck,body and tail parts of the pancreas.Statistical analysis was performed by using Kruskal-Wallis and Wilcoxon signed rank tests.Results The ADCs in the head,neck,body and tail parts of the pancreas was (1.52 ± 0.29) × 10-3,( 1.64 ± 0.34) ×10-3,(1.67±0.35) × 10-3,(1.58 ±0.31) × 10-3 mm2/s,the Kruskal-Wallis test results showed a significant difference of mean ADCs among the different anatomical regions (chi square =44.8748,P ＜0.0001 ).Wilcoxon signed rank test results showed the mean ADCs differed remarkably between the head and neck ( P ＜ 0.0001 ),head and body ( P ＜ 0.0001 ),head and tail ( P =0.0008 ),neck and tail (P =0.0062 ),body and tail (P ＜0.0001),respectively.The mean ADCs between the neck and body was not significantly different (P =0.1181 ).Conclusions The mean ADC values of normal pancreas vary significantly within different anatomical regions,which can serve as a guide for DW1 and ADC in clinical application and research of pancreatic diseases.

Objective To investigate the predictive factors for malignancy and invasive carcinoma of IPMN, and the survival rates of different pathological type of IPMN were compared. Methods Seventy-eight patients with IPMN admitted to Changhai Hospital from January 1993 to September 2009, who underwent surgery with histological evidence were retrospectively analyzed. The univariate and multivariate analysis of potential predictive factors, including medical history, clinical presentations, liver function, CEA, CA19-9,and imaging findings was conducted to identify the predictive factors for malignancy and invasive carcinoma of IPMN. Results Univariate analysis identified jaundice, acute pancreatitis history, CA19-9 Level > 37U/ml,AKP, unclear border of tumour as independent predictive factors for malignancy and invesiveness, main pancreatic duct dilation, branch pancreatic duct diameter > 30 mm, presence of mural modules were identified as malignancy predictor. CEA > 6 ng/ml was identified as invasive carcinoma predictor. Multivariate analysis identified one independent predictive factor for malignancy or invasive carcinoma: unclear border of tumour.Another factor of invasive IPMN was acute pancreatitis. The 5 year survival rate for benign 1PMN was 100%,while 2 year survival rate for malignant IPMN was 78.9%, 5 year survival rate was 68.5%. The 2 year survival rate for invasive IPMN was 64.6%, 5 year survival rate was 43.1%. Conclusions Unclear border of tumour was predictive factors for malignancy; acute pancreatitis and unclear border of tumour were predictive factors for invasive carcinoma.

Objective To evaluate the influence of Helicobacter pylori (Hp) eradication on clinical manifestations, endoscopic features and pathological findings of chronic gastritis. Methods This was a multiple-center, prospective and randomized cohort study. Patients with non-atrophy chronic gastritis from January 2009 to December 2010 were randomized into 3 groups as Hp positive group with eradication, Hp positive group without eradication and Hp negative group. Clinical manifestations, endoscopic findings and pathologic changes of inflammation were compared before and after administration of gastric mucosal protective agent for 8 weeks. Results A total of 211 patients were recruited. Changes of symptom score, endoscopic erosion and mucosal inflammation were significantly different before and after treatment in 3 groups. The decrease in symptom scores of eradication group was ( 3.56 ± 1.37 ), which was significantly higher than that of non-eradication group (2. 80 ± 1.30, P ＜0. 01 ). The decrease of mucosal inflammation and inflammatory activity scores in eradicate group was 1.08 ± 1.34 and 1.42 ± 1.09, respectively, which were also significantly higher than those of the eradication group (0. 49 ± 1.47 and 0. 61 ± 1.34, P ＜0. 01 ). But the improvement of endoscopic erosion in 2 groups showed no significant difference. There were no significant differences in these variables between non-eradication group and Hp-negative group ( P ＞ 0. 05 ). Conclusion For chronic non-atrophic gastritis patients with positive Hp infection, combination of mucosal protective agents and Hp eradication can achieve better improvement in symptoms and gastric inflammation repair.