Research On Algorithms Of3-D Vessel Straightening

Cardiovascular disease leads to a very high mortality rate, terribly harmful to human health. Along with the development of computer and medical imaging technology, the medical image is playing a significant role in clinical diagnosis. Through the analysis and the processing of2-D image sequence, we can realize vessel straighting, which is of great significance in improving the level of medical diagnosis.The study of3-D vascular straightening algorithm in this paper is an important part of the3-D vascular analysis system. The key to the algorithm is extracting accurate vascular central axis. Firstly, a vascular central axis extraction algorithm based on tracking is studied, which is based on the user’s interaction to provide initial key points. In the process of tracking, planes are generated perpendicular to the direction of tracking, and the center points of the blood vessel are calculated. Then a sequence of center points is fitted into a line to obtain central axis. In order to use the3-D information contained in the2-D image sequence efficiently, a multiscale model based algorithm is studied. In this algorithm, the local blood vessel is approximated into tubular structure. The geometric moment is calculated to get the center of gravity of tubular structure as the center of the local blood vessel. A multiscale Gaussian filter based on the eigenvalue analysis of the Hessian matrix is locally applied at a voxel to enhance the tubular structure and estimate the orientation of the blood vessel. After we get the central axis of the blood vessel we can straighten and reconstruct it. The first step in reconstruction process of blood vessel is to sample central axis equal-spaced to get interval center points. Then a new sequence of planes perpendicular to the direction of the blood vessel is generated. Stacking together on all the planes, we can get the sections of different angles of the blood vessel or reconstruct the3-D model, achieving the purpose of straightening the blood vessel.These algorithms studied in this paper are applied to coronary artery and abdominal aortic CT images. The testing results show that the algorithm based on tracking is relatively effective to both single and multiple-branches blood vessel detection, which can straighten the blood vessel successfully. Another algorithm based on multiscale model is mainly applied to single blood vessel at present, which also can straighten the blood vessel successfully.