Application of 3D Ultrasonic Volume Renderingo Detect the Variation of Liver Tissue
Date Issued
2008
Date
2008
Author(s)
Wu, Wen-Hao
Abstract
Liver is the biggest organ in human body, it lies in the right upper abdomen of human body. The function of liver is quite complicated. Besides storing energy and making bile, it can also get rid of the toxin that produced after metabolism. The diagnosis methods for liver diseases include: 1. Liver function test - Check by blood, 2. Ultrasound, 3. Biopsy. For ultrasound, B-mode image is the mostly used method in hospital, and it is a kind of 2D human cross section image. B-mode image offers really few information to a person who doesn’t undergo professional training or even doctors who don’t have enough of experience. When the liver pathological changes takes place, what we are relatively interested in is the variation process of soft tissue within the liver. We hope that we can develop a new 3D ultrasonic image to distinguish the variation of liver tissue by the way of vision and the method of statistics.o distinguish the variation of the liver which has been affected by alcohol is the experimental works done in this thesis. In order to make the characteristics of liver tissue change, we soak the pork liver in the alcohol. The liver is put into water tank while soaking in the alcohol, and use a 3D-controlled step-motor to scan. Then keep the liver in the water tank and scan once again at a regular period. This research uses volume rendering as a tool, and the method used is ray casting. Volume rendering projects the 3D ultrasonic signal data on a 2D plane to form the image. In this thesis, how to choose the most proper length of projection route is discussed also. We use the length of projection route that we find to analyze the experimental data.he experimental result is compared to find the difference before and after soaking the pork liver in the alcohol using the intensity image and central frequency image. Through the increasing of image intensity, the intensity image is apter to observe the variation of liver tissue. The information of the central frequency image is very abundant, and it is not influenced by blood vessel like the intensity image. The central frequency image can show the information of soft tissue, but it is not apter to observe the variation of liver tissue. Because the central frequency image is difficult to observe the variation of liver tissue, we use histogram to quantify the image. We can find that there is trend of downward skew in the central frequency after the pork liver is soaked in alcohol. We ckeck the change of the central frequency image in time, then it is found that the change is not unanimous. So we make the images scanned in short time to improve the analysis. We found finally that the central frequency may change in short time, and the change on the central frequency is swifter than the change on the intensity
Subjects
3D ultrasonic image
volume rendering
central frequency
projection route
liver tissue
SDGs
Type
thesis
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