1 The necessity of medical image fusion
1.1 The fusion of images is the need for technological updating With the wide application of computer technology in medical imaging, new technologies are gradually replacing the traditional ones, and the application of image archiving and PACS as well as the implementation of telemedicine signify that a new model has been established on the technologies of storing and transmitting image information. And the image post-processing technology must also synchronize the development of the original basis for continuous improvement and innovation in order to better and more comprehensively play the advantages of imaging. The fusion of images will be a comprehensive update of post-processing technology.
1.2 The fusion of images to make up for the shortcomings of the single check imaging At present, imaging means from ultrasound, traditional X-ray to DSA, CR, CT, MRI, PET, SPECT, etc., can be said to be rich and colorful, the various checks have their own characteristics and advantages, but in the imaging of the deficiencies, there are certain limitations. For example: CT examination has high resolution, but it is difficult to distinguish tissues with very close density, and at the same time, it is easy to produce bony artifacts, especially in the posterior cranial fossa, which affects the diagnostic accuracy; MRI examination, although it has superb display ability for soft tissues, shows poorly for bony lesions and calcified foci; if the two kinds of imaging of the same site can be fused together, it will comprehensively reflect the normal tissue structure and abnormal changes, thus compensating for the shortcomings of either single test imaging.
1.3 The fusion of imaging is a clinical necessity. Diagnostic imaging ultimately serves clinical treatment; advanced means of examination and clear images help to improve diagnostic accuracy, and the integration of a variety of advantages of the examination of the new image will make the diagnosis more clear, and can better assist the clinical diagnosis and treatment of disease.
2 Feasibility of medical imaging fusion
2.1 The existence of various imaging tests **** and complementary for the fusion of imaging to lay the foundation Although each test has a different inspection mode, imaging principles and imaging characteristics, but they have **** the same morphological basis, are through the image to reflect the morphology of the normal tissues and organs, structure and physiological function, as well as the anatomy, pathology, and metabolism of the lesions. The anatomy, pathology and metabolism of the changes. Moreover, the defects and deficiencies in imaging of each examination can be compensated and improved in other examinations. For example: traditional X-ray, CT examination can make up for the lack of bone imaging; MRI examination can make up for the lack of soft tissue and spinal cord imaging; PET, SPECT examination can make up for the lack of functional determination.
2.2 The application of digital technology in medical imaging provides methods and means for image fusion Now, digital technology has been fully applied to the acquisition, storage, post-processing, transmission, reproduction and other important technical aspects of the image. In the primary link, i.e., the acquisition of images, a variety of technical means are applied, including: (1) simultaneous acquisition of digital information for real-time processing; (2) simultaneous acquisition of analog signals, which are converted into digital signals by analog-to-digital conversion devices; (3) digital conversion of film for certain traditional examinations such as ordinary X-rays, etc., by means of image scanners and digital cameras; and conversion of acquired ordinary images into digital images and Storage and transmission in the form of data files provide the prerequisites for further implementation of image fusion.
3 Key technologies for medical image fusion
The role of information fusion in medical image research is generally described by the synergistic effect, and the implementation of image fusion is to realize the synergy of medical images; image data conversion, image data correlation, image database and image data understanding are the key technologies for fusion. (1) Image data conversion is the format conversion, 3D orientation adjustment, and scale transformation of image information from different acquisition devices to ensure that the likenesses/voxels of multi-source images express the same size of the actual spatial area, and to ensure the consistency of multi-source images on the spatial description of tissues and organs. It is the basic of image fusion. (2) Image fusion first realizes the alignment of related images, that is, the one-to-one correspondence from point to point. And the higher the image resolution, the more image details, the more difficult it is to realize the alignment. Consequently, the alignment of high-resolution images (e.g., CT images and MRI images) is currently performed with the help of external markers. (3) Establishment of an image database is used to accomplish the archiving and management of typical cases and typical image data as well as the extraction of information. It is the data support for fusion. (4) Data comprehension is to synthesize and apply the information obtained from various imaging devices in order to obtain new information for clinical diagnosis
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