Fan G, Sun B, Wu Z, Guo Q, Guo Y
Department of Radiology, China Medical University Second Hospital, Heping Dist, Shenyang, Liaoning, People's Republic of China.
Clin Radiol. 2004 Jan;59(1):77-85. doi: 10.1016/j.crad.2003.08.006.
To determine whether single-voxel proton magnetic resonance spectroscopy (1HMRS) could be used to differentiate gliomas from metastases on the basis of differences in metabolite levels in the different involved regions.
Twenty-two patients (age range from 32 to 62 years, with a median age of 46.7 years) with a solitary brain tumour (14 gliomas, eight metastases) underwent conventional, gadolinium-DTPA enhanced T1-weighted images, and 1HMRS before surgical resection. Spectra from the enhancing tumour, the peritumoural region, and normal brain were obtained from 1HMRS. A point resolved spectroscopy sequence was required for 1HMRS. The metabolites in the spectra include: N-acetylaspartate (NAA), choline (CHO), creatine compounds (CR), myo-inositol (MI), lactate (LAC), glutamate and glutamine (Glu-n). Relative concentrations of metabolites were related to the peak area, and expressed with reference to CR. Student's t-test was used to determine whether there was a statistically significant difference in relative metabolic ratios between high-grade gliomas and metastases. Meanwhile, 16 of all 22 patients were re-examined using magnetic resonance imaging (MRI) within 6 months of surgical resection. Recurrence was present in three patients (two gliomas, one metastasis).
Of the 14 patients with gliomas, the peaks of NAA were reduced in three cases; the peaks of LAC, which were elevated, appeared as typical double-peaks in the peritumoural region in nine cases; the peaks of Glu-n, which were also elevated, had a zigzag appearance in seven cases. The peaks of MI were increased in the tumoural region in eight cases, and CHO levels were elevated in all 14 cases. Of the eight patients with metastases, Glu-n peaks in the tumoural region in three cases and CHO peaks in the tumoural region in four cases were elevated, respectively, while the peaks of CR were reduced in three cases, and the peaks of NAA were markedly reduced in four cases within the enhancing tumoural region. Elevated CHO levels (CHO-to-CR ratio was 4.98:1.46, 2.65:0.32) in both the tumoural and peritumoural regions of gliomas but not in the metastases (CHO-to-CR ratio was 1.37:0.92, 1.22:0.38), and elevated MI levels were present (MI-to-CR ratio was 1.67:0.35) within the enhancing foci of gliomas but not in the metastases (MI-to-CR ratio was 0.89:0.31). The difference was statistically significant (p<0.01). Elevated Glu-n and lipid levels were present in all three patients with recurrences.
1HMRS is a useful method in the distinction of these two kinds of tumours. It may also may provide useful prognostic information.
基于不同受累区域代谢物水平的差异，确定单体素质子磁共振波谱（1HMRS）是否可用于鉴别胶质瘤与转移瘤。
22例（年龄范围32至62岁，中位年龄46.7岁）患有孤立性脑肿瘤（14例胶质瘤，8例转移瘤）的患者在手术切除前接受了常规、钆喷酸葡胺增强T1加权成像及1HMRS检查。通过1HMRS获取增强肿瘤、瘤周区域及正常脑组织的波谱。1HMRS需要使用点分辨波谱序列。波谱中的代谢物包括：N-乙酰天门冬氨酸（NAA）、胆碱（CHO）、肌酸化合物（CR）、肌醇（MI）、乳酸（LAC）、谷氨酸和谷氨酰胺（Glu-n）。代谢物的相对浓度与峰面积相关，并以CR为参照进行表达。采用学生t检验来确定高级别胶质瘤与转移瘤之间相对代谢比率是否存在统计学显著差异。同时，22例患者中的16例在手术切除后6个月内接受了磁共振成像（MRI）复查。3例患者出现复发（2例胶质瘤，1例转移瘤）。
14例胶质瘤患者中，3例NAA峰降低；9例LAC峰升高，在瘤周区域呈现典型双峰；7例Glu-n峰也升高，呈锯齿状。8例肿瘤区域MI峰升高，14例患者CHO水平均升高。8例转移瘤患者中，3例肿瘤区域Glu-n峰升高，4例肿瘤区域CHO峰升高，3例CR峰降低，4例增强肿瘤区域内NAA峰明显降低。胶质瘤的肿瘤及瘤周区域CHO水平升高（CHO与CR的比值分别为4.98:1.46、2.65:0.32），而转移瘤中未升高（CHO与CR的比值分别为1.37:0.92、1.22:0.38），胶质瘤增强灶内MI水平升高（MI与CR的比值为1.67:0.35），转移瘤中未升高（MI与CR的比值为0.89:0.31）。差异具有统计学显著性（p<0.01）。3例复发患者Glu-n和脂质水平均升高。
1HMRS是鉴别这两种肿瘤的有效方法。它也可能提供有用的预后信息。
