Vascular diseases, such as ischemic heart disease, infarction, aneurysms, stroke and stenosis are a leading cause of serious long-term disability and their mortality rate is as high as that of cancers in many countries. Recently, neurovascular intervention using catheters is a minimally-invasive endovascular technique used to treat vascular disease of the brain, and a navigation system for catheters has been developed to facilitate surgical planning and to provide intra-operative assistance. Since the mechanical properties of a catheter play an important role in reaching the targeted disease, tracking of catheter movement during endovascular treatment may be useful to increase confirmation of the rate of successful operation. In this study, we developed an in vitro tracking system for catheter motion using poly (vinyl alcohol) hydrogel (PVA-H) to mimic an arterial wall. The employed models were made of PVA-H, which is sufficiently transparent to permit observation of catheter movement in the artery. This system is expected to contribute to validation of computer-based navigation systems for surgical assistance.

Keywords

Endovascular Treatment, Catheter Motion, Tracking System, Poly (vinyl alcohol) Hydrogel, Biomodel

Paper information

ChangHo YU, Hiroyuki KOSUKEGAWA, Keisuke MAMADA, Kanju KUROKI, Kazuto TAKASHIMA, Kiyoshi YOSHINAKA and Makoto OHTA, “Development of an In Vitro Tracking System with Poly (vinyl alcohol) Hydrogel for Catheter Motion”, Journal of Biomechanical Science and Engineering, Vol. 5, No. 1 (2010), pp.11-17 . doi:10.1299/jbse.5.11

Cardiovascular diseases are closely related to blood flow. Ultrasonic-Measurement-Integrated (UMI) simulation, in which results of ultrasonic measurement are fed back to the flow simulation, was proposed in a previous study in order to reproduce the real blood flow accurately and efficiently. The usability of the UMI simulation was confirmed by numerical experiment, but the effectiveness of this simulation was strongly affected by the accuracy of the ultrasonic measurement. In this paper, we examined the accuracy of a commercial ultrasonic measurement device by an experiment with a PVA-H straight tube phantom. By analyzing the measured color Doppler images for a developed laminar flow inside the phantom, we obtained the relationship between the color Doppler value and the Doppler velocity (C-V relationship). It was revealed that the original C-V relationship provided in the device as a color bar was not suitable for quantitative evaluation of Doppler velocity to be used in UMI simulation. Compared with the original C-V relationship, the present C-V relationship results are in far better agreement with the analytic solution. Investigation of the normalized error confirmed that the result obtained with the present C-V relationship was reliable in cases of relatively high Reynolds number in the flow domain except near the wall. The two signal conditioning factors of the device had little influence on the Doppler velocity. Finally, we investigated the effect of temporal and spatial averaging of ultrasonic measurement data to clarify the relation between the number of averagings and the level of agreement with the analytic solution.

Keywords

Ultrasonic Measurement Integrated Simulation, Blood Flow, Ultrasonic Measurement, In Vitro Validation, PVA-H

Paper information

Lei LIU, Toshiyuki HAYASE, Makoto OHTA and Kosuke INOUE, “Experimental Validation of Color Doppler Velocity Measurement for Ultrasonic-Measurement-Integrated Simulation of Blood Flow”, Journal of Biomechanical Science and Engineering, Vol. 3, No. 2 (2008), pp.161-175 . doi:10.1299/jbse.3.161