Zhang Qi, Eagleson Roy, Peters Terry M
MR Research & Development Research Group, National Research Council Institute for Biodiagnostics, Winnipeg, MB, Canada.
IEEE Trans Inf Technol Biomed. 2012 Sep;16(5):878-90. doi: 10.1109/TITB.2012.2205011. Epub 2012 Jun 18.
In minimally invasive image-guided interventions, different imaging modalities, such as magnetic resonance imaging (MRI), computed tomography (CT), and 3-D ultrasound (US), can provide complementary, multispectral image information. Dynamic image registration is a well-established approach that permits real-time diagnostic information to be enhanced by placing lower-quality real-time images within a high quality anatomical context. For the guidance of cardiac interventions, it would be valuable to register dynamic MRI or CT with intra-operative US. However, in practice, either the high computational cost prohibits such real-time visualization, or else the resulting image quality is not satisfactory for accurate interventional guidance. Modern graphics processing units (GPUs) provide the programmability, parallelism and increased computational precision to address this problem. In this paper, we first outline our research on dynamic 3-D cardiac MR and US image acquisition, real-time dual-modality registration and US tracking. Next, we describe our contributions on image processing and optimization techniques for 4-D (3-D + time) cardiac image rendering, and our GPU-accelerated methodologies for multimodality 4-D medical image visualization and optical blending, along with real-time synchronization of dual-modality dynamic cardiac images. Finally, multiple transfer functions, various image composition schemes, and an extended window-level setting and adjustment approach are proposed and applied to facilitate the dynamic volumetric MR and US cardiac data exploration and enhance the feature of interest of US image that is usually restricted to a narrow voxel intensity range.
在微创图像引导介入手术中，不同的成像模态，如磁共振成像（MRI）、计算机断层扫描（CT）和三维超声（US），可以提供互补的多光谱图像信息。动态图像配准是一种成熟的方法，它通过将低质量的实时图像置于高质量的解剖学背景中，来增强实时诊断信息。对于心脏介入手术的引导而言，将动态MRI或CT与术中超声进行配准将很有价值。然而，在实际应用中，要么是高计算成本阻碍了这种实时可视化，要么是所得图像质量对于精确的介入引导而言并不令人满意。现代图形处理单元（GPU）提供了可编程性、并行性以及更高的计算精度来解决这一问题。在本文中，我们首先概述我们在动态三维心脏MR和US图像采集、实时双模态配准以及US跟踪方面的研究。接下来，我们描述我们在四维（三维 + 时间）心脏图像渲染的图像处理和优化技术方面的贡献，以及我们用于多模态四维医学图像可视化和光学融合的GPU加速方法，还有双模态动态心脏图像的实时同步。最后，我们提出并应用了多种传递函数、各种图像合成方案以及一种扩展的窗宽 - 窗位设置和调整方法，以促进动态容积MR和US心脏数据的探索，并增强通常局限于狭窄体素强度范围的US图像的感兴趣特征。
