Roy Snehashis, Carass Aaron, Prince Jerry
Image Analysis and Communication Laboratory, Dept. of Electrical and Computer Engg., The Johns Hopkins University, USA.
Inf Process Med Imaging. 2011;22:371-83. doi: 10.1007/978-3-642-22092-0_31.
The tissue contrast of a magnetic resonance (MR) neuroimaging data set has a major impact on image analysis tasks like registration and segmentation. It has been one of the core challenges of medical imaging to guarantee the consistency of these tasks regardless of the contrasts of the MR data. Inconsistencies in image analysis are attributable in part to variations in tissue contrast, which in turn arise from operator variations during image acquisition as well as software and hardware differences in the MR scanners. It is also a common problem that images with a desired tissue contrast are completely missing in a given data set for reasons of cost, acquisition time, forgetfulness, or patient comfort. Absence of this data can hamper the detailed, automatic analysis of some or all data sets in a scientific study. A method to synthesize missing MR tissue contrasts from available acquired images using an atlas containing the desired contrast and a patch-based compressed sensing strategy is described. An important application of this general approach is to synthesize a particular tissue contrast from multiple studies using a single atlas, thereby normalizing all data sets into a common intensity space. Experiments on real data, obtained using different scanners and pulse sequences, show improvement in segmentation consistency, which could be extremely valuable in the pooling of multi-site multi-scanner neuroimaging studies.
磁共振（MR）神经影像数据集的组织对比度对诸如配准和分割等图像分析任务有重大影响。无论MR数据的对比度如何，保证这些任务的一致性一直是医学成像的核心挑战之一。图像分析中的不一致部分归因于组织对比度的变化，而这种变化又源于图像采集过程中的操作员差异以及MR扫描仪的软件和硬件差异。由于成本、采集时间、疏忽或患者舒适度等原因，给定数据集中完全缺少具有所需组织对比度的图像也是一个常见问题。缺少这些数据会妨碍科学研究中对部分或所有数据集进行详细的自动分析。本文描述了一种使用包含所需对比度的图谱和基于块的压缩感知策略，从可用的采集图像中合成缺失的MR组织对比度的方法。这种通用方法的一个重要应用是使用单个图谱从多个研究中合成特定的组织对比度，从而将所有数据集归一化到一个共同的强度空间。使用不同扫描仪和脉冲序列获得的真实数据实验表明，分割一致性有所提高，这在多站点多扫描仪神经影像研究的汇总中可能极其有价值。
