Jirák Daniel, Dezortová Monika, Hájek Milan
Department of Diagnostic and Interventional Radiology Institute for Clinical and Experimental Medicine, Videnska 1958/9, Prague, Czech Republic 140 21.
Med Phys. 2004 Mar;31(3):616-22. doi: 10.1118/1.1646231.
The application of texture analysis (TA) in magnetic resonance imaging (MRI) requires the availability of texture phantoms for use in the standardization of in vivo measurements. The aims of our study were (a) to develop a new type of phantoms suitable for MRI and TA and test their long-term stability; (b) to optimize the choice of texture parameters describing the phantoms; (c) to compare different MR imagers according to texture parameters in a multi-center study. A long-term study performed at 4.7 T proved that the developed phantom based on polystyrene spheres and an agar gel solution is stable at least 12 months. This phantom, with nodular patterns, was found useful for the modeling of structural differences. The comparison of TA parameters at 4.7 and 7 T proved that the same parameters can be used for the separation of structures. The proposed algorithm of the selection of TA parameters shows that there exists a part of texture parameters which can be measured with high reproducibility (1-3%); on the other hand, their absolute values can differ by more than 30% if the textures differ. Results obtained from the multi-center study of whole body MR imagers show the wide variation in the misclassification rates at the different sites and point out the importance of the set up of MR sequences.
纹理分析（TA）在磁共振成像（MRI）中的应用需要有纹理体模，用于体内测量的标准化。我们研究的目的是：（a）开发一种适用于MRI和TA的新型体模，并测试其长期稳定性；（b）优化描述体模的纹理参数的选择；（c）在多中心研究中根据纹理参数比较不同的MR成像仪。在4.7 T下进行的一项长期研究证明，基于聚苯乙烯球和琼脂凝胶溶液开发的体模至少12个月内是稳定的。这种具有结节状图案的体模被发现可用于模拟结构差异。在4.7 T和7 T下对TA参数的比较证明，相同的参数可用于结构分离。所提出的TA参数选择算法表明，存在一部分纹理参数可以以高重现性（1-3%）进行测量；另一方面，如果纹理不同，它们的绝对值可能相差超过30%。从全身MR成像仪的多中心研究中获得的结果表明，不同部位的错误分类率差异很大，并指出了设置MR序列的重要性。
