Two Dimensional Pseudo-Wiener Filtering in Ultrasonic Imaging for Nondestructive Evaluation Applications

This paper deals with the use of a two dimensional pseudo-Wiener filter for ultrasonic image enhancement. Experimental results are presented to demonstrate the effectiveness of the technique for the improvement of the lateral resolution and image enhancement of ultrasonic images in materials such as graphite/epoxy composites and stainless steel. The difficulties encountered in the implementation of the filter will be delineated. Methods of overcoming some of these ‘implementational hurdles’ will be suggested

Schistosomal portal hypertension. Assessment of portal bood flow before and after surgical treatment

Objetivo: Avaliar o fluxo sanguíneo portal na esquistossomose hepato-esplênica e o efeito tardio do tratamento cirúrgico na hemodinâmica portal. Método: Foram estudados 64 pacientes por Doppler dúplex: grupo I (pacientes com hipertensão portal esquistossomótica); grupo II (pacientes submetidos a desconexão ázigo-portal com esplenectomia) e grupo III (pacientes submetidos derivação esplenorrenal distal). Resultados: O fluxo da veia porta foi maior no grupo I (1954,46 ± 693,73ml/min) e foi menor no grupo III (639,55 ± 285,86ml/min), neste correlacionou-se com o tempo pós-operatório (r=-0,67, p=0,0005). O fluxo sangüíneo portal do grupo II (1097,18 ± 342,12ml/min) foi semelhante ao de indivíduos normais. As mesmas alterações foram verificadas com relação ao diâmetro da veia porta nos grupos I, II, e III (cm): 1,46 ± 0,23; 1,12 ± 0,22; 0,93 ± 0,20, respectivamente. Conclusões: Estes dados sugerem que: 1) Existe hiperfluxo portal na fisiopatologia da hipertensão portal esquistossomótica; 2) o tratamento cirúrgico interferiu na hemodinâmica portal, diminuindo o fluxo sangüíneo da veia porta; 3) Esta redução do fluxo sangüíneo portal correlacionou-se com o tempo de seguimento pós-operatório no grupo III mas não no grupo II. _________________________________________________________________________________________ ABSTRACT: Background: Assessment of the portal blood flow in hepatoesplenic schistosomosis and the late effect of surgical treatment on portal hemodynamics. Method: Were studied 64 patients by duplex scan: group I (patients with schistosomal portal hypertension); group II (patients who underwent esophagogastric devascularization and splenectomy); group III (patients who underwent distal splenorenal shunt). Results: Portal vein blood flow was the highest in group I (1954.46 ± 693.73 ml/min) and the lowest in group III (639.55 ± 285.86 ml/min) which correlated with follow-up time (r=-0.67, p=0.0005). Group II portal flow (1097.18 ± 342.12 ml/min) was similar to control. The same changes were seen in portal vein diameter in groups I, II, III (cm): 1.46 ± 0.23, 1.12 ± 0.22, 0.93 ± 0.20, respectively. Conclusions: Our data suggest that: 1) there is portal overflow in the physiopathology of schistosomal portal hypertension; 2) surgical treatment has interfered in hemodynamic reducing portal venous blood flow; 3) portal venous blood flow reduction correlated with follow-up time in group III but not in group II