N.V. Anisimov, S.S. Koretskaya, M.V. Gulyaev, E.V. Verkhoglazova, Yu.A. Pirogov
MRI data processing based on algebraic operations (subtraction, multiplication, etc.) with identical images on localization is considered. Subtraction of images is usually applied at MRI researches with injection of contrast substance, and also in fMRI. We used algebraic operations for differentiation of tissues and emulation of MR-images which cannot be received at usual scanning.
Operations are made with the numbers displaying brightness which in turn displays intensity of signals from corresponding voxel. The main attention is aimed to emulate scanning modes with suppression of signals from normal tissues - especially fat and water. In this case lesions are visualized very distinctly and their volume reconstructions are produced very easily.
Method is based on known theoretical dependence of MR-signals on relaxation time, parameters of used modes of scanning and influence on pixel brightness of algebraic operations over these images. Method is easy realized by use inversion-recovery pulse sequences - for example FLAIR and STIR.
Algebraic operations were produced with the images received on MR-scanners: 0.5T Tomikon_S50 (Bruker) and 3T Achieva (Philips). For emulation of modes STIR or FLAIR the subtraction of images was fulfilled ac-cordingly: (T2WI-FLAIR) or (T2WI-STIR). Acquisition with identical parameters was used in all scanning modes. Real and emulated images were very similar. Operation of subtraction (T2WI-FLAIR) gave the images similar to ones from STIR mode. It helped to revealing of dermoid cysts, recognition of tissues at the skull base.
Operation (T2WI-FLAIR)×FLAIR yielded the image similar to image from DIR mode that has allowed to reveal postoperative changes in brain meninges. Operation (T2WI-FLAIR)×FLAIR gave image of dermoid cyst as hy-per intensive formation on a dark background. Emulated images gave good visualization of intracranial le-sions. It is very useful for volume reconstruction. The software has been developed for simultaneous viewing on monitor T2WI, FLAIR and their algebraic derivatives.
The images are received by algebraic operations with real MR-images, have a specific contrast. Results of some operations can be considered as emulation of images from modes of scanning which are useful for di-agnostics. The analysis of these images helps to reveal suspicious (pathological) zones and to receive the in-formation about specificity of their tissues.
Algebraic operations with MR images can be involved for automatic recognition of pathologically changed structures. The method is simple in realization, it has a large potential for development.