Quantitative in vivo diffusion imaging of cartilage using double echo steady-state free precession
Quantitative in vivo diffusion imaging of cartilage using double echo steady-state free precession
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DOI：
10.1002/mrm.23275
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发表时间：
2012-09-01
影响因子：
3.3
通讯作者：
Scheffler, Klaus
中科院分区：
文献类型：
--
作者：
Bieri, Oliver;Ganter, Carl;Scheffler, Klaus
单次激发回波平面成像技术通常用于弥散加权成像（DWI），但对于T2较短的物种，其空间分辨率和视野覆盖范围相当差。相比之下，稳态自由进动（SSFP）已显示出有前途的结果，DWI的肌肉骨骼系统，但量化通常受到其突出的灵敏度弛豫时间。在这项工作中，一个新的和真正的扩散加权（即弛豫时间无关）SSFP DWI技术采用双回波稳态方法。在此框架内（这与使用SSFP-Echo的常见SSFP DWI技术相反），采集非平衡SSFP的两个主要回波路径，即FID和Echo。模拟和体外测量结果表明，回波/FID信号比的两个双回波稳态扫描采集与扩散敏化失相时刻和没有提供了一个高度弛豫独立的量扩散量化。因此，在3.0 T条件下，使用扩散加权双回波稳态扫描对膝关节和踝关节进行了人体关节软骨的弛豫独立高分辨率（0.4 x 0.4 - 0.6 x 0.6 mm 2平面内分辨率）定量体内SSFP DWI。软骨（D 1.01.5 μ m2/ms）和滑液（D 2.6 μ m2/ms）的扩散系数与以前的工作是一致的。Magn Reson Med，2012年。(c)2011 Wiley Periodicals，Inc.
Single-shot echo-planar imaging techniques are commonly used for diffusion-weighted imaging (DWI) but offer rather poor spatial resolution and field-of-view coverage for species with short T2. In contrast, steady-state free precession (SSFP) has shown promising results for DWI of the musculoskeletal system, but quantification is generally hampered by its prominent sensitivity on relaxation times. In this work, a new and truly diffusion-weighted (that is relaxation time independent) SSFP DWI technique is introduced using a double-echo steady-state approach. Within this framework (and this is in contrast to common SSFP DWI techniques using SSFP-Echo) both primary echo paths of nonbalanced SSFP are acquired, namely the FID and the Echo. Simulations and in vitro measurements reveal that the ratio of the Echo/FID signal ratios of two double-echo steady-state scans acquired with and without diffusion sensitizing dephasing moments provides a highly relaxation independent quantity for diffusion quantification. As a result, relaxation-independent high-resolution (0.4 x 0.4 - 0.6 x 0.6 mm2 in-plane resolution) quantitative in vivo SSFP DWI is demonstrated for human articular cartilage using diffusion-weighted double-echo steady-state scans in the knee and ankle joint at 3.0 T. The derived diffusion coefficients for cartilage (D 1.01.5 mu m2/ms) and synovial fluid (D 2.6 mu m2/ms) are in agreement with previous work. Magn Reson Med, 2012. (c) 2011 Wiley Periodicals, Inc.