Information theoretic analysis of plaque in MR imaging

Magnetic resonance (MR) imaging and analysis have become one of the most important tools in medical research and clinical applications. To quantitatively evaluate the quality of MR images, some research work has been done previously. However, most of the research was only based on 2D spin echo images which can hardly be applied to atherosclerosis study. In this paper, we apply Shannon's information theory for optimal MR imaging and lesion index analysis. First, we review the information content (IC) which is used as a subjective criterion of image quality measurement in our work. Then we extend the existing spatial spectrum model to the 3D time-of-flight (ToF) imaging technique and find the optimal imaging resolution with which the maximum image information content can be obtained. A theoretical proof of its uniqueness is also given. At last, a lesion index system is proposed and developed for the blood vessel wall plaque analysis in our study. It is used to determine atherosclerotic lesion complexity and identify lesion changes over time. Some phantom and in vivo MR images are analyzed along with examples to demonstrate the performance.