Sundgren P C, Nagesh V, Elias A, Tsien C, Junck L, Gomez Hassan D M, Lawrence T S, Chenevert T L, Rogers L, McKeever P, Cao Y
Department of Radiology, University of Michigan University Health Systems, Ann Arbor, Michigan 48109, USA.
J Magn Reson Imaging. 2009 Feb;29(2):291-7. doi: 10.1002/jmri.21657.
To assess if interval changes in metabolic status in normal cerebral tissue after radiation therapy (RT) can be detected by 2D CSI (chemical shift imaging) proton spectroscopy.
Eleven patients with primary brain tumors undergoing cranial radiation therapy (RT) were included. 2D-CSI MRS was performed before, during, and after the course of RT with the following parameters: TE/TR 144/1500 ms, field of view (FOV) 24, thickness 10 mm, matrix 16 x 16. The metabolic ratios choline/creatine (Cho/Cr), N-acetylaspartate (NAA)/Cr, and NAA/Cho in normal brain tissue were calculated.
NAA/Cr and Cho/Cr were significantly decreased at week 3 during RT and at 1 month and 6 months after RT compared to values prior to RT (P < 0.01). The NAA/Cr ratio decreased by -0.19 +/- 0.05 (mean +/- standard error [SE]) at week 3 of RT, -0.14 +/- 0.06 at the last week of RT, -0.14 +/- 0.05 at 1 month after RT, and -0.30 +/- 0.08 at 6 months after RT compared to the pre-RT value of 1.43 +/- 0.04. The Cho/Cr ratio decreased by -0.27 +/- 0.05 at week 3 of RT, -0.11 +/- 0.05 at the last week of RT, -0.26 +/- 0.05 at 1 month after RT and -0.25 +/- 0.07 at 6 months after RT from the pre-RT value of 1.29 +/- 0.03. Changes in Cho/Cr were correlated with the interaction of the radiation dose and dose-volume at week 3 of RT, during the last week of RT (P < 0.005), and at 1 month after RT (P = 0.017).
The results of this study suggest that MRS can detect early metabolic changes in normal irradiated brain tissue.
评估二维化学位移成像（2D CSI）质子波谱能否检测放疗（RT）后正常脑组织代谢状态的间期变化。
纳入11例接受颅脑放疗（RT）的原发性脑肿瘤患者。在放疗疗程前、疗程中及疗程后进行二维化学位移成像磁共振波谱（2D-CSI MRS）检查，参数如下：回波时间（TE）/重复时间（TR）为144/1500毫秒，视野（FOV）为24，层厚10毫米，矩阵为16×16。计算正常脑组织中的代谢比值，即胆碱/肌酸（Cho/Cr）、N-乙酰天门冬氨酸（NAA）/Cr和NAA/Cho。
与放疗前相比，放疗第3周、放疗后1个月和6个月时，NAA/Cr和Cho/Cr显著降低（P<0.01）。与放疗前1.43±0.04的值相比，放疗第3周时NAA/Cr比值下降了-0.19±0.05（平均值±标准误差[SE]），放疗最后一周时下降了-0.14±0.06，放疗后1个月时下降了-0.14±0.05，放疗后6个月时下降了-0.30±0.08。与放疗前1.29±0.03的值相比，放疗第3周时Cho/Cr比值下降了-0.27±0.05，放疗最后一周时下降了-0.11±0.05，放疗后1个月时下降了-0.26±0.05，放疗后6个月时下降了-0.25±0.07。在放疗第3周、放疗最后一周（P<0.005）和放疗后1个月（P=0.017）时，Cho/Cr的变化与辐射剂量和剂量体积的相互作用相关。
本研究结果表明，磁共振波谱能够检测正常放疗脑组织的早期代谢变化。
