3.0 T单体素磁共振波谱成像离体及在体检测2-羟基戊二酸效能初探  

Efficiency of 2-hydroxyglutarate quantification by long-echo proton magnetic resonance spectroscopy at 3.0 T in vitro and in vivo

作　　者：俞梅美 沈慧聪[1] 沈智威[2] 林梅影 侯欣怡[1] 陈红燕[1] 陈绪珠[1] 季楠[3] YU Meimei;SHEN Huicong;SHEN Zhiwei;LIN Meiying;HOU Xinyi;CHEN Hongyan;CHEN Xuzhu;JI Nan(Department of Radiology,Beijing Tiantan Hospital Affiliated to Capital Medical University,Beijing 100070,China;Department of Radiology,Second Affiliated Hospital of Shantou University Medical College,Shantou 515000,China;Department of Neurosurgery,Beijing Tiantan Hospital Affiliated to Capital Medical University,Beijing 100070,China)

机构地区：[1]首都医科大学附属北京天坛医院放射科,北京100070 [2]汕头大学医学院第二附属医院放射科,汕头515000 [3]首都医科大学附属北京天坛医院神经外科,北京100070

出　　处：《磁共振成像》2020年第4期275-280,共6页Chinese Journal of Magnetic Resonance Imaging

基　　金：国家重点研发计划项目(编号:2018YFC0115604);国家自然科学基金项目(编号:81772005)。

摘　　要：目的通过氢质子磁共振波谱技术(proton magnetic resonance spectroscopy,^1H-MRS)离体及在体检测异柠檬酸脱氢酶(isocitrate dehydrogenase,IDH)突变后产生的代谢物2-羟基戊二酸(2-hydroxyglutarate,2HG),探索临床3.0 T核磁共振机应用长回波时间(echo time,TE)单体素不对称自旋回波点解析波谱(point-resolved spectroscopy,PRESS)序列检测2HG的效能。材料与方法配制包含不同代谢物的两组体外水模,于T2WI液体衰减反转恢复序列(fluid attenuated inversion recovery,FLAIR)像上对各水模中心位置进行MRS感兴趣定位,采用长TE PRESS序列进行MRS成像。使用相同扫描参数,结合患者T1WI、T1WI增强图像,对拟诊为低级别胶质瘤的4例患者进行脑MRS成像,以术后基因检测获得的IDH基因突变状态作为金标准。水模及在体波谱中代谢物的绝对浓度值均通过LC model软件拟合后获得。结果体外水模扫描结果显示,当2HG配制浓度在2~16 mmol/L时,均能有效检测出2HG,相比2HG配制的真实浓度值,通过LC model计算得到的2HG绝对浓度值降低,而水模中2HG/谷氨酸(glutamate,Glu)的浓度比值与实际比值接近。在体扫描结果显示,在符合入组标准的3例患者中,2例IDH突变型胶质瘤患者均有效检测出2HG蓄积,1例IDH野生型胶质瘤未检测出2HG蓄积。结论水模扫描结果表明,临床环境中通过长TE PRESS序列检测2HG浓度水平时,低浓度2HG会被掩盖,从而增加假阴性的结果。而2HG/Glu的比值与实际比值较为接近,提示用比值替代绝对浓度可能更具准确性。结合在体扫描结果表明,临床环境中,在常规胶质瘤影像序列中加入长TE PRESS序列检测2HG蓄积水平,从而间接预测IDH基因突变状态具有较好的可行性,这对于胶质瘤分子分型的术前无创诊断、指导治疗策略及预后评估具有重要意义。Objective:Mutated isocitrate dehydrogenase(IDH)produce high accumulation levels of 2-hydroxyglutarate(2 HG)that can be quantitatively detected by proton magnetic resonance spectroscopy(^1H-MRS).Through in vitro and in vivo studies,the purpose of our study was to explore the efficacy of using long-echo(TE)point-resolved spectroscopy(PRESS)MRS to detect 2 HG at 3.0 T in clinical setting.Materials and Methods:Two phantoms were set up,the first is a spherical phantom(diameter of about 6 cm plastic ball),which containing a range of known concentrations of 2 HG 9 mmol/L,Glutamate(Glu)12.5 mmol/L,Glutamine(Gln)12.5 mmol/L,γ-Aminobutyric Acid(GABA)2.0 mmol/L,N-acetylaspartate(NAA)12.5 mmol/L,Creatine(Cr)10.0 mmol/L,Choline(Cho)3.0 mmol/L;The second includes six cylindrical gradient phantoms(both 60 mL plastic test tubes),and Glu 10 mmol/L,Cr 10 mmol/L,and 2 HG 0.5,1,2,4,8,16 mmol/L,respectively.Point-resolved spectroscopy(PRESS)sequence with long echo time(TE=97 ms,TE1=26 ms,TE2=71 ms)MRS was used to analyze for all the set phantoms.In addition,combined with T1 WI and T1 WI enhanced images,long TE PRESS MRS was performed on 4 subjects with suspected diagnosis of low-grade glioma in our study.IDH mutation status obtained by postoperative genetic testing was taken as the gold standard.The absolute concentration values of metabolites were acquired by LC model software fitting.Results:Phantoms results showed that 2 HG could be detected effectively when the concentration of 2 HG was 2-16 mmol/L.Compared with the real concentration of 2 HG,the absolute concentration of 2 HG obtained by LC model software was lower,while the concentration ratio of 2 HG/Glu was close to the actual ratio.Three subjects were subsequently diagnosed histologically as gliomas,of which 2 were IDH mutant gliomas and 1 was IDH wild-type glioma.By long TE PRESS,the accumulation of 2 HG was detected effectively in IDH mutant glioma,while there is no accumulation of 2 HG in IDH wild-type glioma.Conclusions:The results of phantoms suggest that 2 HG at low c

关 键 词：2-羟基戊二酸 异柠檬酸脱氢酶 神经胶质瘤 磁共振波谱 

分 类 号：R445.2[医药卫生—影像医学与核医学] R739.41[医药卫生—诊断学]