| The diagnosis of cerebral atherosclerosis is pivotal for the therapy of cerebrovascular disease. Ultrasonic diagnosis has the merit of being non-traumatic, intuitionistic image, real time, convenience, low-cost and short report. It has the preponderance over other image technique. Ultrasonic is necessary in the diagnosis of cerebral atherosclerosis.The thesis analysed the cause of cerebral atherosclerosis. It always locates in main or middle artery such as internal carotid artery, middle cerebral artery, anterior cerebral artery, posterior cerebral artery, vertebral artery and vertebrobasilar, whose diameter is beyond 500μm . Altherosclerotic plaques are irregularly nubby in arterial intima, which are composed of collagen fibers, elastic fiber, vascular smooth muscle cells, macrophages, foam cell and adipocytes. It intumesces to the hemocoele with a diameter of 0.3-1.5cm. They can be joined seriously.There are some diagnostic tools in common use such as rheoencephalogram, electroencephalogram and TCD. But the report is not intuitionistic in readability. Only experienced doctor can read it. So subjectivity was added into the result. Ultrasonography resolved the problem in some degree. Ultrasonic diagnosis system based on PACS can obtain image from all hospital. It can also manage these pictures. Telemedicine consultation and network teaching can be carried through Wide Area Network. It is an inevitable trend of digital hospital.SPECK and SPIHT are best in low complexity image compression. They are efficient and simple. Their image coding is based on absolute embedded orwavelet transform that is fast. There are some noises in ultrasonic image when they come into being because of tissue character and interference. If the algorithm based on edge detection and region growing supplement each other in practice, there would be better for image segmentation.Bring forward some new standpoints, the thesis emphasize on algorithm study of 3D ultrasonic image. The volume rendering is based on visibility voxel projection. (1) Shear-warp algorithm decomposes the line of volume rendering sight in order to predigest the projection from the object space to image space. And it was used in the visualization of parallel ultrasonic scan about blood vessel. (2) The datum opacity is used, and its exponent is the opacity of diversified information. Iterative multiplication of cumulative opacity is displaced by the iterative addition of datum opacity. A new composite colors method based on image rulers comes into being. The method expedites imaging and does not influence the quality. (3) It will omit the opaque ergodic image area and voxel that an interactive shear-warp Volume rendering algorithm based on fast classification with Octree. That will save a great deal of repeat time. (4) Increasing middle projection plane will avoid fringes distortion.DICOM is a techno-base of researching and developing modern medical instruments, which have Network function with resource sharing. Popularizing DICOM standard will simplify the design of medical information system and avoid tautology so that quicken the development. It is important for telemedicine and hospital without film or paper.3D ultrasonic image is significant direction in the development of ultrasonic medicine. Cerebrovascular disease will be conquered with the development of technology farther and unremitting strive of medical fraternity. There will be diversified new diagnosis methods about the disease keep people away from suffering.
|
PDF Full Text Request