Development of a Statistical Medical Image and Data Processing System

本课题的研究目的是在以往统计图像处理研究成果的基础上，开发一个统计医学图像及数据处理系统。为了实现这一目标，我们按照以下三个步骤进行了研究。首先，从计算成本方面改进了之前开发的PET和SPECT重构算法以及MRI图像分割算法。通常，统计图像和数据处理算法需要大量的计算成本，因为它们是基于预定义成本函数的最小化。然而，改进算法的计算成本与常用算法相当。为了实现这一目标，我们引入了数学规划领域中的块迭代概念和一些优化方法。其次，针对医学成像中出现的新问题，开发了基于统计估计的图像处理算法。例如，这些包括基于少量血管造影x射线投影数据的三维血管重建，PET和SPECT的分段衰减图重建，以及基于医学图像序列的光流计算。为了实现这一目标，我们使用了数学规划领域的优化方法、拓扑约束图像标记和小波变换等新概念。最后，将所有开发的软件统一在一个工作站内，使其具有相同的数据格式和相同的用途，并将一些用户界面（如图像显示）结合起来。我们用一些现有的数据来评估该图像和数据处理系统的性能。

The aim of this research project is to develop a statistical medical image and data processing system based on our previous research results on statistical image processing. To achieve this aim, we performed the research according to the following three steps. First, we improved the PET and SPECT reconstruction algorithm and the MRI image segmentation algorithm which we developed previously in terms of computational costs. In general, statistical image and data processing algorithms require a lot of computational costs because they are based on the minimization of pre-defined cost functions. However, the improved algorithms worked with reasonable computational costs comparable to those of the commonly used algorithms. To achieve this aim, we introduced the concept of block iterations and some optimization methods in the field of mathematical programming. Second, we developed image processing algorithms based on statistical estimation for new problems appearing in medical imaging. For example, these include 3-D blood-vessel reconstruction from a few angiographc x-ray projection data, segmented attenuation map reconstruction for PET and SPECT, and optical flow computation from medical image sequences. To achieve this aim we used new concepts such as optimization methods in the field of mathematical programming, topology-constrained image labeling, and wavelet transform. Finally, all the developed softwares are unified in a workstation such that they work with the same data format and the same usage, and some user-interfaces such as image display are combined too. We evaluated the performances of this image and data processing system with several existing data.