3D Virtual Endoscopy Of Cardiovascular System

According to statistical data, cardiovascular disease has become the No.1 diseasewhich cause deaths in recent years. Find out new ways to improve the diagnosticmethods for such disease will make sense in increase the cure rate. Therefore,researches in this area has great realistic significance.Due to the characteristic of cardiovascular system, we introduce virtualendoscope(VE) into this area, make improvements and innovations for its keytechniques. A prototype of VE system is designed and brought about in this article. Ituses the high quality image from dual-source CT(DSCT) to over come the difficultythat CT can not get the clear image of the moving organs such as heart. Doctors canuse this VE system to look into the the cardiovascular system, estimate the state of anillness.Four key techniques of VE will be discussed in this article. They are tissuesegmentation, path planning, 3D reconstruction and real time display.In tissue segmentation, we make use of the contrast medium for segmentation.First, the CT value are analysed. Then, region growing algorithm extract the region ofinterest. Finally, morphological image processing are applied to get a bettersegmenting result. Compared with other VE system, the inovations of this thesis arethat path planning, 3D reconstruction and real time display will all be associated withthe geometric information derived from the segmenting result.The 3D Euclidean distance are calculated and a Dijkastra algorithm used it asweight is empolyed into path planning. It can produce precise central path quickly.After that, the four-chamber view of heart is estimated based on the 3D EuclideanDistance and the geometric characteristics of the center line.Two 3D reconstruction algorithm are accomplished, 3D texture mapping anddirect volume rendering(raycasting) based on CUDA. The former one has goodrendering speed performance even in low-end graphic hardware, but the latter one hasbetter image quality and resolution. The latter one is an algorithm that make full useof CUDA computing power. In addition to transform serial algorithm into paiallel one,the 3D Euclidean distance is used to skip to void voxels. So the compute Capacity isreduced, and the rendering speed is improved.Accompany with VE viewport to watch the interior of the chambers of the heart,a 3D viewport which can mutually clip the 3D image is designed. With these twoviewport, the user of VE system can have a clear relationship between global andlocal.