Vanderbilt University Institute of Imaging Science, Vanderbilt University, Nashville, Tennessee.
Department of Radiology and Radiological Sciences, Vanderbilt University, Nashville, Tennessee.
Magn Reson Med. 2018 Sep;80(3):1110-1117. doi: 10.1002/mrm.27128. Epub 2018 Feb 9.
To evaluate the ability of spin-lock imaging to detect the uptake of 3-o-methyl-D-glucose (3oMG) in normal brain and brain tumors in animals.
Measurements of the longitudinal relaxation rate in the rotating frame (R) were made over a range of spin-lock powers in rat brains bearing 9L tumors. The dispersion of R values was quantified by ΔR, the difference of R values acquired with low and high locking powers. The glucose analogue 3-o-methyl-D-glucose (3oMG) was administered intravenously and the differences of ΔR values (ΔR) before and as a function of time after administration were calculated to isolate the contribution of 3oMG to the dispersions, which at high fields mainly reflects chemical exchange effects. In addition, the ratio of image signals from low and high locking fields (the spin-lock ratio, SLR), which requires fewer acquisitions and varies directly with ΔR, was computed as an alternative measure of the variation with locking power, and changes in SLR (SLR) after 3oMG were evaluated.
Both ΔR and SLR in tumors increased rapidly after injection, whereas intact brain showed a gradual increase up to 1h. ΔR and SLR were significantly different between tumors and contralateral normal tissues.
Spin-lock methods can be used to detect 3oMG after injection, and appropriate analyses of MRI signals allow tumors to be distinguished from normal brain.
评估自旋锁定成像检测动物正常脑组织和脑肿瘤摄取 3-o-甲基-D-葡萄糖（3oMG）的能力。
在携带 9L 肿瘤的大鼠脑中，测量了一系列自旋锁定功率下的纵向旋转框架弛豫率（R）。通过 ΔR 量化 R 值的分散度，ΔR 为低锁定功率和高锁定功率下 R 值的差值。静脉注射葡萄糖类似物 3-o-甲基-D-葡萄糖（3oMG），计算给药前后 ΔR 值（ΔR）的差异，以分离 3oMG 对分散度的贡献，在高场主要反映化学交换效应。此外，计算低锁定场和高锁定场的图像信号比（自旋锁定比，SLR），作为另一种测量与锁定功率变化的替代方法，评估 3oMG 后 SLR 的变化（SLR）。
肿瘤内的 ΔR 和 SLR 在注射后迅速增加，而完整的大脑则在 1 小时内逐渐增加。肿瘤内的 ΔR 和 SLR 与对侧正常组织明显不同。
自旋锁定方法可用于检测注射后的 3oMG，适当分析 MRI 信号可区分肿瘤与正常脑组织。
