Research And Application On The Algorithm For Coronal Artery Analysis

Cardiovascular disease has seriously endangered the human being's health, which has been usually caused by plaques and stenosis in coronary artery. At present, the clinicians mainly make use of the medical image observation to diagnose the disease. However, this kind of method has some disadvantages, such as the low correctness and objectivity. Besides, as for the complicated circuity structure, the doctor can not observe its full-stage in the sectional image with a suitable angle. Thereby, some functions, such as the location of the calcified plaques in the coronary artery, the calculation of the calcium score, the accurate segmentation of coronary artery and the curved planar reformation on the CardioCAD image have provided the significant diagnosis evidence for the doctor to quantitatively analyze the degree of the coronary atherosclerosis, locate the calcified region, ensure the narrow degree of the vessels and its position and observe the full-stage of the vessels and its surroundings tissures from multi-angle. In order to meet the needs for the doctors to apply the CAD software, we studied and realized the algorithm of calcium score module, CPR module and improved the coronary artery segmentation method in the original CardioCAD software so that it increased the accuracy of the segmentation. Main researching works are as follows.Firstly, detect and mark the calcified plaques avoiding the effect of noise on the base of gray value and connectivity; calculate the calcium score and other parameters by various methods to help the doctor diagnose; provide the convenient operations according to doctors' demand; promote the software running speed and reusability by improving the design of the application.Secondly, ensure the judgment rules by the shape characteristics of the transversal section of the vessels and the gray gradient generated by the contrast media for the different tissues on the basis of the center line of the vessels; carry out the region growing algorithm using the accurately located vessel center point as the interest pointe and then obtain the accurate segmentation result.. It was obvious that this method could avoid the over-segmentation andinsufficient segmentation and could locate the position and edge of the vessel more exactly compared to the original method.Thirdly, actualize the curved planar reformation by combining the stretched CPR, straightened CPR with rotating CPR. Thus, the doctor could observe the whole vessel and its surrounding tissues from multiple perspectives. The thick CPR was also reformed in order to reduce the sensitivity to the position of the vessel's center line and increase the space information in the stretched CPR and straightened CPR. Furthermore, the software could automatically adjust the reforming methods to be consistent with doctors'viewing habits and provide the correct position of organs. It was also suitable for other different circuity structures besides vessels. The length of vessel was measured in CPR image, and it was compared with those in 3D image. The result showed that the vessels'length in CPR was more approximately to the actual curve length.