Research Of The Image Processing Technology For The Cerebrovascular Images By DSA

The cerebrovascular disease is very common in our lives, which is frequently occurred, and causes much death every year. The Digital Subtraction Angiography is widely used in the treatment of the cerebrovascular disease and the interventional therapeutic procedures of intravascular at a clinic. However, the traditional DSA imaging technique leads to vessels overlap, many efforts have been made to develop 3D reconstruction of cerebral blood vessels from subtracted rotational angiography projections.This article is about the Research of the Image Processing Technology for the Cerebrovascular Images by Digital Subtraction Angiography. And it mainly research the part of geometry correction of distortion and the three dimensional reconstruction algorithm.In the part of the geometry correction of distortion, the distorted grid picture, which was collected by the X-ray image intensifier, has been corrected with the local technique and some correlative morphological knowledge. Then, there are several compare between local and global technique on the performance of the arithmetic and the results of correction. The characteristics and excellence of those two techniques have been summarized as well. Finally, I use the local technique to process the simulation grid image, and carry on the quantification analysis.In the part of the three dimensional rebuild algorithms, I have introduced and realized the Feldkamp algorithm. According to the Feldkamp algorithm, the Central Slice Theorem, the Filtered Back projection and the sector rebuild algorithm are introduced firstly. Then I have analyzed the Feldkamp algorithm and use it to process the projection image of blood vessel which is formatted of Dicom. Finally, I carried the Feldkamp algorithm on the spheroid model, and compare the result with the blood vessel image.After the processing, the local technique correction has a good result, but it is worse than the result by global technique in the smoothness of images. The suggestion of the next step is process the images using the both methods. The Feldkamp algorithm, which is the main three-dimensional rebuild algorithm, can completely process the two-dimensional projection data to the three dimensional data field. But because of the error of the DICOM images in measuring, the result of the blood vessel images is not very well. The suggestion of the next step is to find the measuring error, and get a way to correct it, and then rebuild the DICOM images again.