ABSTRACT
Objective To investigate a self-designed catheter pump by using computational fluid dynamics (CFD) method, so as to predict its hydraulic performance and risk of thrombosis formation. Methods The thrombosis prediction models proposed by Grigioni and Danny Bluestein were used. The shear stress and exposure time during platelet motion were calculated by CFD method, and parameters of platelet activation state (PAS) were obtained for prediction of thrombogenic performance. Results At the flow rate of 4 L/min and rotating speed of 10 000 r/min, the differential pressure of the pump reached 14.763 kPa and the hydraulic performance was proved to fit the requirement of left ventricular assist device. The PAS values of Grigioni model and Danny Bluestein model were 6.35×10-6 and 7.68×10-4,respectively, both at a very low level, indicating a low possibility of thrombus formation. Conclusions This study investigated the feasibility of thrombosis prediction based on simulation method and the predicted hydraulic performance and thrombosis will provide references for further design optimization.
ABSTRACT
Objective To estimate the value of contrast-enhanced harmonic endoscopic ultrasonography(CEH-EUS)on differential diagnosis of pancreatic mass. Methods Multiple Chinese and English databases were retrieved to selected relevant literature.The quality of literature was assessed,and the data were meta-analyzed using Metadisc 1.4 and STATA 14.0 software. Results A total of 16 researches with 1 352 patients were included. The pooled sensitivity, specificity, positive likelihood ratio, negative likelihood ratio,and diagnostic odds ratio was 93%(95%CI: 92%-95%), 84%(95%CI:80%-87%), 5.82(95%CI: 4.06-8.33), 0.08(95%CI: 0.06-0.10), and 77.33(95%CI: 52.37-114.17), respectively. The area under the summary receiver operating characteristic curve was 0.96(95%CI: 0.94-0.97). The results of subgroup analysis demonstrated that the number of cases, region, QUADAS scores, the diameter and type of mass,and the experience of diagnostician were not the source of heterogeneity.After 2 articles with larger bias were eliminated,the heterogeneity dropped to an acceptable range,and the pooled sensitivity,specificity,positive predictive value and negative predictive value had no significant change. All these suggested that the results of meta-analysis were reliable. Conclusion CEH-EUS has a high accuracy in differential diagnosis of pancreatic mass,and can be used as an effective diagnostic method.