胶质瘤术前分级诊断的1H MRS相对定量的临床应用

Preoperative grading of gliomas by using metabolite relative quantification with proton magnetic resonance spectroscopy

关键词:  脑肿瘤  磁共振成像  磁共振波谱

Key words:  brain tumor  MRI  MR spectroscopy

摘要:

［目的］探讨磁共振氢质子波谱（¹H MRS）相对定量对胶质瘤术前分级的临床应用价值。［方法］前瞻性对48例胶质瘤（低级别11例，高级别37例）行2D多体素¹H MRS检查，分析肿瘤实质、周围水肿区(距肿瘤强化外缘1 cm以内的区域定义为近侧瘤周，1 cm以外的区域为远侧瘤周)和对侧正常表现实质的¹H MRS谱线表现，并测量各种代谢物比值：Cho/NAA、Cho/Cr、NAA/ Cr、Cho/nCho，并进一步与病理结果对照。［结果］高级别胶质瘤瘤体实质、近侧瘤周水肿区的Cho/NAA分别为3.44±0.99、2.13±0.74，分别明显高于低级别胶质瘤瘤体实质（1.77±0.57，P＜0.05）、近侧瘤周水肿区（1.14±0.23，P＜0.01）。高级别胶质瘤近、远瘤周水肿区的Cho/NAA差异有显著性意义（P＜0.05）。分别以瘤体实质、近侧瘤周水肿区Cho/NAA值2.30、1.35为阈值来鉴别高、低级别胶质瘤，则敏感性分别为88.35%、96.15％，特异性为70.53%、75.00％。高、低级别胶质瘤远侧瘤周水肿区的各代谢物比值无统计学差异（P≥0.05）。［结论］¹H MRS可以为术前确定胶质瘤级别提供定量诊断依据。

Abstract:

［Objective］To investigate metabolite relative quantification of ¹H MRS in diagnosing of gliomas grade.［Methods］Forty-etght patients suspectd of having gliomas(31 males and 17 females, mean age, 50.16 years) underwent 2D proton spectroscopic MR imaging. Metabolic ratios including of Cho/NAA, Cho/Cr, NAA/Cr、Cho/nCho was done among tumoral parenchyma, peritumoral edematous areas and contralateral normal appearance brain tissue(NABT) were calculated. The peritumoral signal abnormality was divided into two regions to allow investigation of metabolic ratios varies with distance of from the enhancing portion of the tumor. The immediate peritumoral area was defined to be within a 1 cm distance from the outer enhancing tumor margin; the distant peritumoral region was defined as greater than 1 cm from the tumor. All cases were confirmed by surgery and pathology, which were divided into 11 cases of low grade gliomas and 37 cases of high grade ones.［Results］Significantly higher ratio of Cho/NAA was found in tumoral parenchyma (3.44 0.99, P＜0.05) and immediate peritumoral area(2.13±0.74, P＜0.05) of high grade gliomas compared with low grade ones(1.77±0.57, 1.14±0.23). Among high grade gliomas , ratio of Cho/NAA in the immediate peritumoral area is significantly higher than one in the distant peritumoral region (P＜0.05).Two Cho/NAA threshold of 2.30 and 1.35 in tumoral parenchyma and immediate peritumoral area provided respectively for sensitivity by 88.35% and 96.15% as well as specificity by 70.53% and 75.00% in differentiation high-grade from low-grade gliomas.［Conclusions］Metabolite Relative Quantification with ¹H MRS was useful complementary methods in diagnosing of gliomas grade.