Hsu Y Y, Chang C, Chang C N, Chu N S, Lim K E, Hsu J C
Department of Radiology, Chang Gung Memorial Hospital, Taipei, Taiwan, Republic of China.
AJNR Am J Neuroradiol. 1999 Apr;20(4):643-51.
Proton MR spectroscopy has recently been applied to the evaluation of seizures, but few comparisons have been made between different clinical spectroscopic techniques. Our goal was to determine whether there is a significant difference between hippocampal NAA/(Cho+Cr) ratios obtained by single-voxel spectroscopy (SVS) and by chemical-shift imaging (CSI).
Twelve healthy adults and eight patients with complex partial seizures were studied on a 1.5-T MR scanner using a proton SVS method. Another 12 healthy adults and 10 patients with complex partial seizures were recruited for a proton CSI study, which was performed on a different 1.5-T MR system. The NAA/(Cho+Cr) ratio was calculated from the integral peak areas by curve fitting. The two-tailed t-test was used for statistical analysis.
The mean value +/- standard deviation of the hippocampal NAA/(Cho+Cr) ratio in healthy control subjects was 0.63 +/- 0.07 by SVS, with 0.62 +/- 0.15 for the anterior hippocampus and 0.65 +/- 0.11 for the posterior hippocampus by CSI. There was no significant difference between the control group data obtained by SVS and those by CSI, nor was there a regional difference in the CSI NAA/(Cho+Cr) ratio in the hippocampus. Relative to the control group, the patients with seizures had a significant decrease in the NAA/(Cho+Cr) ratio in the abnormal hippocampus: -28% by SVS, and -24% in the anterior hippocampus and -18% in the posterior hippocampus by CSI. Proton SVS and CSI detected hippocampal abnormalities, unilateral or bilateral, in all patients of each group.
Under similar measurement conditions, proton SVS and CSI provide similar NAA/(Cho+Cr) ratios among healthy control subjects, and they possess comparable ability for detecting hippocampal abnormalities in patients with complex partial seizures.
质子磁共振波谱分析最近已应用于癫痫发作的评估，但不同临床波谱技术之间的比较较少。我们的目标是确定通过单体素波谱分析（SVS）和化学位移成像（CSI）获得的海马NAA/（Cho+Cr）比值之间是否存在显著差异。
使用质子SVS方法在一台1.5-T磁共振成像扫描仪上对12名健康成年人和8名复杂部分性癫痫患者进行研究。另外招募了12名健康成年人和10名复杂部分性癫痫患者进行质子CSI研究，该研究在另一台1.5-T磁共振系统上进行。通过曲线拟合从积分峰面积计算NAA/（Cho+Cr）比值。采用双侧t检验进行统计分析。
通过SVS测量，健康对照受试者海马NAA/（Cho+Cr）比值的平均值±标准差为0.63±0.07，通过CSI测量，海马前部为0.62±0.15，海马后部为0.65±0.11。SVS获得的对照组数据与CSI获得的数据之间无显著差异，海马CSI的NAA/（Cho+Cr）比值也无区域差异。与对照组相比，癫痫患者异常海马的NAA/（Cho+Cr）比值显著降低：SVS降低28%，CSI测量时海马前部降低24%，海马后部降低18%。质子SVS和CSI在每组所有患者中均检测到单侧或双侧海马异常。
在相似的测量条件下，质子SVS和CSI在健康对照受试者中提供相似的NAA/（Cho+Cr）比值，并且它们在检测复杂部分性癫痫患者海马异常方面具有相当的能力。
