Objectives

Objectives

Three-dimensional (3D) power Doppler data is increasingly used to assess and quantify blood flow and tissue perfusion. The objective of this study was to assess the validity of common 3D power Doppler 'vascularity' indices by quantification in well characterised in-vitro flow models. A computer driven gear pump was used to circulate a steady flow of a blood mimicking fluid through various well characterised flow phantoms to investigate the effect of the number of flow channels, flow rate, depth dependent tissue attenuation, blood mimic scatter particle concentration and ultrasound settings. 3D Power Doppler data were acquired with a Voluson 530D scanner and 7.5MHz transvaginal transducer (GE Kretz). Virtual Organ Computer-aided Analysis software (VOCAL) was used to quantify the vascularisation index (VI), flow index (FI) and vascularisation-flow index (VFI). The vascular indices were affected by many factors, some intuitive and some with more complex or unexpected relationships (e.g. VI increased linearly with an increase in flow rate, blood mimic scatter particle concentration and number of flow channels, and had a complex dependence on pulse repetition frequency). Use of standardised settings and appropriate calibration are required in any attempt at relating 'vascularity indices' with flow.

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The pipeline inspection is a key requirement to maintain structural health and pipeline integrity for oil and gas transportation over countries. Pipe failure is a critical problem that needs to be endured within the operational work. The defects or flaws existence on pipeline surface is one of the most leading factors to pipe failures. A new approach of non-destructive technique is implemented to monitor flaws on pipeline by using reflection-mode ultrasonic tomography system. This paper details on the hardware development of ultrasonic tomography system based on reflection mode detection. The system consists of ultrasonic transceiver sensors mounted circularly and contactless to the pipe surface. The modeling work described the ultrasonic ring configuration, ultrasonic signal behavior, sensors arrangement and image grid estimation. The developed instrumentation system is used to detect external and internal flaws on pipe surface. The results show that the reflection-mode ultrasonic tomography is capable to differentiate flaws detected based on the calculated depth verified from the distance measured and through the reconstructed image.

No abstract