Fischmann Arne, Morrow Jasper M, Sinclair Christopher D J, Reilly Mary M, Hanna Michael G, Yousry Tarek, Thornton John S
University of Basel Hospital, Department of Radiology, Division of Diagnostic and Interventional Neuroradiology, Basel, Switzerland; University of Basel Childrens Hospital, Basel, Switzerland; MRC Centre for Neuromuscular Diseases, Department of Molecular Neuroscience, UCL Institute of Neurology, London, United Kingdom.
J Magn Reson Imaging. 2014 Apr;39(4):1033-8. doi: 10.1002/jmri.24220. Epub 2013 Oct 7.
To compare the influence of two limb positions and slice prescription using scout-image-based and surface-anatomy-based methods on the reproducibility of quantitative MRI of lower-limb muscles.
Ten healthy subjects were scanned at 3 Tesla with a two-dimensional turbo spin-echo T1-weighted acquisition. Imaging was performed at thigh and calf level in two subject limb positions and independently repeated by a second operator. Regions-of-interest (ROI) were drawn on three muscles at thigh and calf levels on axial slices at fixed distance from the knee joint and at a level determined by surface anatomy.
Test-retest reliability of muscle cross-sectional area and ROI area overlap were similar for both limb positioning methods. Changing limb position between scans reduced ROI overlap (P < 0.01). Scout-image-based slice prescription resulted in narrower limits of agreement and higher intraclass correlation coefficients compared with surface-anatomy-based slice prescription.
Slice prescription based on fixed distance from the knee joint provided superior reproducibility of slice location than a surface anatomy-based method and should be used for longitudinal quantitative MRI studies. Exact subject positioning will depend on scanner and coil configuration, but should be consistent through a longitudinal study.
比较基于定位像和基于表面解剖学的方法，在两种肢体位置及层面定位情况下，对下肢肌肉定量MRI重复性的影响。
对10名健康受试者进行3T扫描，采用二维快速自旋回波T1加权成像。在受试者的两种肢体位置下，于大腿和小腿水平进行成像，并由另一名操作人员独立重复操作。在距膝关节固定距离的轴向层面以及由表面解剖学确定的层面上，在大腿和小腿的三块肌肉上绘制感兴趣区（ROI）。
两种肢体定位方法在肌肉横截面积的重测信度和ROI面积重叠方面相似。扫描之间改变肢体位置会降低ROI重叠率（P < 0.01）。与基于表面解剖学的层面定位相比，基于定位像的层面定位具有更窄的一致性界限和更高的组内相关系数。
与基于表面解剖学的方法相比，基于距膝关节固定距离的层面定位在层面位置的重复性方面表现更优，应在纵向定量MRI研究中使用。准确的受试者定位将取决于扫描仪和线圈配置，但在纵向研究中应保持一致。
