MR Center, Department of Radiology, Medical University of Vienna, Lazarettgasse 14, Vienna, Austria,
Skeletal Radiol. 2013 Nov;42(11):1565-72. doi: 10.1007/s00256-013-1699-z. Epub 2013 Aug 23.
The purpose of our study was to assess T2 and T2* relaxation time values of patella cartilage in healthy volunteers using three different coils at 3.0 Tesla MRI and their influence on the quantitative values.
Fifteen volunteers were examined on the same 3-Tesla MR unit using three different coils: (i) a dedicated eight-channel knee phased-array coil; (ii) an eight-channel multi-purpose coil, and (iii) a one-channel 1H surface coil. T2 and T2* relaxation time measurements were prepared by a multi-echo spinecho respectively a gradient-echo sequence. A semi-automatic region-of-interest analysis was performed for patella cartilage. To allow stratification, a subregional analysis was carried out (deep-superficial cartilage layer). Statistical analysis-of-variance was performed.
The mean quantitative T2 values showed statistically significant differences in all comparison combinations. The differences between the mean quantitative T2* values were slightly less pronounced than the T2 evaluation and only the comparison between (i) and (ii) showed a significant difference. The results of T2 and T2* values showed, independent of the used coil, higher values in the superficial zone compared to the deep zone (p < 0.05). Looking at the signal alterations, all coils showed clearly higher values (and thus more signal alterations as a sign of noise) in the deep layer. The validation of the reliability showed a high intra-class correlation coefficient and hence a very high plausibility (ICC was between 0.870 and 0.905 for T2 mapping and between 0.879 and 0.888 for T2* mapping).
The present results demonstrate that biochemical T2 and T2* mapping is significantly dependent on the utilized coil.
本研究旨在评估 3.0T MRI 下三种不同线圈对健康志愿者髌软骨 T2 和 T2*弛豫时间值的影响及其定量值的影响。
15 名志愿者在同一 3.0T 磁共振仪上使用三种不同的线圈进行检查：（i）专用 8 通道膝关节相控阵线圈；（ii）8 通道多用途线圈；（iii）1 通道 1H 表面线圈。T2 和 T2*弛豫时间测量分别采用多回波自旋回波和梯度回波序列进行。采用半自动感兴趣区分析对髌软骨进行分析。为了进行分层，进行了亚区分析（深层-浅层软骨层）。进行方差分析。
所有比较组合的平均定量 T2 值均存在统计学显著差异。平均定量 T2值的差异稍小，且仅（i）和（ii）之间的比较存在显著差异。T2 和 T2值的结果表明，无论使用哪种线圈，浅层区的数值均高于深层区（p<0.05）。从信号变化来看，所有线圈在深层均显示出明显更高的（因此作为噪声的标志）信号变化。可靠性验证显示，组内相关系数高，因此可信度非常高（T2 映射的 ICC 介于 0.870 和 0.905 之间，T2*映射的 ICC 介于 0.879 和 0.888 之间）。
本研究结果表明，生化 T2 和 T2*映射显著依赖于所使用的线圈。
