Musculoskeletal MRI at 3.0T: Relaxation times and image contrast
Musculoskeletal MRI at 3.0T: Relaxation times and image contrast
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DOI：
10.2214/ajr.183.2.1830343
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发表时间：
2004-08-01
影响因子：
5
通讯作者：
Beaulieu, C
中科院分区：
文献类型：
--
作者：
Gold, GE;Han, E;Beaulieu, C
客观的。我们研究的目的是测量 1.5 和 3.0 T 下肌肉骨骼组织的弛豫时间，以优化 3.0 T 下的肌肉骨骼 MRI 方法。 材料和方法。在五名健康志愿者的膝盖中，我们测量了软骨、滑液、肌肉、骨髓和脂肪在 1.5 和 3.0 T 下的 T1 和 T2 弛豫时间。T1 弛豫时间是使用螺旋 Look-Locker 序列测量的，其中沿着 T1 恢复曲线有 8 个样本。使用具有六个回波的螺旋 T2 准备序列测量 T2 弛豫时间。 T1 和 T2 测量序列的准确性和可重复性在体模中得到验证。结果。 3.0 T 时软骨、肌肉、滑液、骨髓和皮下脂肪中的 T1 弛豫时间始终高于 1.5 T 时测量的值。与 1.5 T 相比，3.0 T 时测量的 T2 弛豫时间减少。使用计算和测量的信噪比结果验证体内弛豫时间测量结果。使用松弛时间来开发 3.0 T 膝关节 T2 加权成像的高分辨率协议。结论。 3.0 T MRI 可提高肌肉骨骼成像的分辨率和速度；然而，为了获得最佳图像对比度和信噪比，需要考虑场强和弛豫时间之间的相互作用。使用单次平均采集，可以在更短的时间内以 3.0 T 进行扫描。通过增加 TR 来解决 T1 弛豫时间的增加并获取比 1.5 T 更薄的切片，可以在 3.0 T 下实现高效的高分辨率成像。
OBJECTIVE. The purpose of our study was to measure relaxation times in musculoskeletal tissues at 1.5 and 3.0 T to optimize musculoskeletal MRI methods at 3.0 T.MATERIALS AND METHODS. In the knees of five healthy volunteers, we measured the T1 and T2 relaxation times of cartilage, synovial fluid, muscle, marrow, and fat at 1.5 and 3.0 T. The T1 relaxation times were measured using a spiral Look-Locker sequence with eight samples along the T1 recovery curve. The T2 relaxation times were measured using a spiral T2 preparation sequence with six echoes. Accuracy and repeatability of the T1 and T2 measurement sequences were verified in phantoms.RESULTS. T1 relaxation times in cartilage, muscle, synovial fluid, marrow, and subcutaneous fat at 3.0 T were consistently higher than those measured at 1.5 T. Measured T2 relaxation times were reduced at 3.0 T compared with 1.5 T. Relaxation time measurements in vivo were verified using calculated and measured signal-to-noise results. Relaxation times were used to develop a high-resolution protocol for T2-weighted imaging of the knee at 3.0 T.CONCLUSION. MRI at 3.0 T can improve resolution and speed in musculoskeletal imaging; however, interactions between field strength and relaxation times need to be considered for optimal image contrast and signal-to-noise ratio. Scanning can be performed in shorter times at 3.0 T using single-average acquisitions. Efficient higher-resolution imaging at 3.0 T can be done by increasing the TR to account for increased T1 relaxation times and acquiring thinner slices than at 1.5 T.