Endosonography with linear array instead of endoscopic retrograde cholangiography as the diagnostic tool in patients with moderate suspicion of common bile duct stones

AIM: To evaluate the diagnostic efficiency of endoscopic ultrasound (EUS) as the main imaging modality in patients with moderate suspicion of common bile duct stones (CBDS).METHODS: 55 patients with moderate clinical suspicion of CBDS were prospectively included to the study and evaluated with EUS. This study was done in single blind method in the clinical and biochemical data of patients. EUS was done with echo-endoscope Pentax FG 32-UA (f=5-7,5 MHz) and Hitachi EUB 405 ultrasound machine. Patients diagnosed with CBDS by EUS were excluded from this study and treated with ERC. All the other patients were included to the follow up study obtained by mail every 6 months for clinical evaluation (need of ERC or surgery).RESULTS: CBDS was found in 4 patients by EUS. Diagnosis was confirmed in all cases on ERC. The remaining 51 patients without CBDS on EUS were followed up for 6-26 months (meanly 13 months) There were: 40 women, 42cholecystectomized patients, aged: 55 (mean). Biochemical values (mean values) were as follows: bilirubin: 14,9 μmol.L-1,alkaline phosphatase: 95 IU.L-,1 γ-GTP: 131 IU.L-1, ALT: 50IU.L-1, AST: 49 IU.L-1, Only 1 patient was lost for follow up.In the remaining 50 patients with follow up, there was only 1 (2 %) patient with persistent biliary symptoms in whom CBDS was finally diagnosed by ERC with ES. All other patients remained symptoms free on follow up and did not require ERC or biliary surgery.CONCLUSION: Vast majority of patients with moderate suspicion of CBDS and no stones on EUS with linear array can avoid invasive evaluation of biliary tree with ERC.

Comparison of methods for vibration analysis of electrostatic precipitators

The paper presents two methods for the formulation of free vibration analysis of collecting electrodes of precipitators.The first,called the hybrid finite element method, combines the finit element method used for calculations of spring deformations with the rigid finite element method used to reflect mass and geometrical features,which is called the hybrid finite element method.As a result,a model with a diagonal mass matrix is obtained.Due to a specific geometry of the electrodes,which are long plates of complicated shapes,the second method proposed is the strip method which is a semi-analytical method.The strip method allows us to formulate the equations of motion with a considerably smaller number of generalized coordinates.Results of numerical calculations obtained by both methods are compared with those obtained using commercial software like ANSYS and ABAQUS.Good compatibility of results is achieved.