Herrmann K-H, Wurdinger S, Fischer D R, Krumbein I, Schmitt M, Hermosillo G, Chaudhuri K, Krishnan A, Salganicoff M, Kaiser W A, Reichenbach J R
Medical Physics Group, Institute for Diagnostic and Interventional Radiology, Friedrich-Schiller-Universität Jena, Philosophenweg 3, 07743 Jena, Germany.
Eur Radiol. 2007 Jan;17(1):259-64. doi: 10.1007/s00330-006-0224-3. Epub 2006 Apr 13.
The purpose of this study was to assess the performance of a new motion correction algorithm. Twenty-five dynamic MR mammography (MRM) data sets and 25 contrast-enhanced three-dimensional peripheral MR angiographic (MRA) data sets which were affected by patient motion of varying severeness were selected retrospectively from routine examinations. Anonymized data were registered by a new experimental elastic motion correction algorithm. The algorithm works by computing a similarity measure for the two volumes that takes into account expected signal changes due to the presence of a contrast agent while penalizing other signal changes caused by patient motion. A conjugate gradient method is used to find the best possible set of motion parameters that maximizes the similarity measures across the entire volume. Images before and after correction were visually evaluated and scored by experienced radiologists with respect to reduction of motion, improvement of image quality, disappearance of existing lesions or creation of artifactual lesions. It was found that the correction improves image quality (76% for MRM and 96% for MRA) and diagnosability (60% for MRM and 96% for MRA).
本研究的目的是评估一种新的运动校正算法的性能。从常规检查中回顾性选取了25个受不同程度患者运动影响的动态乳腺磁共振成像（MRM）数据集和25个对比增强三维外周磁共振血管造影（MRA）数据集。匿名数据通过一种新的实验性弹性运动校正算法进行配准。该算法通过计算两个容积的相似性度量来工作，该相似性度量考虑了由于造影剂的存在而预期的信号变化，同时对由患者运动引起的其他信号变化进行惩罚。使用共轭梯度法来找到最佳的运动参数集，以使整个容积的相似性度量最大化。校正前后的图像由经验丰富的放射科医生进行视觉评估并根据运动减少、图像质量改善、现有病变消失或伪影病变的产生进行评分。结果发现，校正可改善图像质量（MRM为76%，MRA为96%）和可诊断性（MRM为60%，MRA为96%）。
