MR二维化学位移成像检测人体肝脏31P代谢物相对量的重复能力

目的探讨MR二维化学位移成像(2D CSI)在人体肝脏磷代谢物相对量检测中的重复能力.方法对浓度为0.05 mol/L的500 ml磷酸盐(NaH2PO4)溶液模体进行6次MR 2D CSI,视野(FOV)200 mm×200 mm,平均次数40次,改变FOV为280 mm×280 mm对5名健康志愿者肝脏各进行6次MR 2D CSI呼吸门控触发扫描.对应代谢物包括磷酸单脂(PME)、无机磷(Pi)、磷酸二脂(PDE)、三磷酸腺苷γ-ATP、α-ATP、β-ATP,利用波谱图上波峰下面积积分值作为对应代谢物的相对量,通过对数据分析得出代谢物相对量检测误差.结果(1)在FOV为200 mm×200 mm,平均次数为40次时,磷酸盐模体检测误差为5.38%.在呼吸门控触发扫描采集下,5名志愿者中代谢物检测的最大误差分别为PME 39.5%、Pi 40.4%、PDE 23.2%、γ-ATP 24.3%、α-ATP 20.1%、β-ATP24.9%.(2)采用呼吸门控时,波谱基线平稳,其方法的合理使用更有助于降低误差;不带呼吸门控,基线严重不平,波形很杂.(3)模体实验中,改变FOV为280 mm×280 mm和400 mm ×400 mm,平均次数为40次的情况下,误差为4.96%和4.47%.在FOV为200 mm×200 mm,平均次数为20、40、80次时,误差分别为8.86%、5.38%和4.40%,扫描采集时间分别为1.27、2.53和5.06 min.结论MR2D CSI在人体肝脏磷代谢物相对量检测中是一种稳定的、值得推广的技术.在使用该方法时,应合理选择扫描参数,并注意各种因素对检测结果的影响.     

31P MR波谱成像在肝脏的初步临床应用研究

目的探讨31P MRS成像技术在肝脏的初步临床应用。方法对5例健康志愿者、5例乙型肝炎肝功能正常病例、5例慢性活动性肝炎肝硬化、5例原发性肝细胞癌病例行常规MR扫描、31P MRS成像。采用GE公司波谱分析软件(spectroscopy analysisGE)校正,并计算细胞内pH值,分析各峰峰值及各比值变化特征。结果正常组5例中4例肝脏31P波谱提供的6种代谢物峰从左至右为:磷酸单脂(PME)、无机磷(P i)、磷酸二脂(PDE)、三磷酸腺苷(γ-ATP、α-ATP、β-ATP)6种。其中1例出现7种峰,多出一种因受腹壁肌肉影响产生的磷酸肌酸(PCr)峰。轻度肝炎组,PME轻度升高,PDE轻度减低,PME/PDE值较正常组略高。慢活肝-肝硬化组6个共振峰中仅PME明显升高。原发性肝细胞癌病例中,PME均明显增高,细胞内pH值呈碱性。结论31PMRS对检测肝脏代谢变化具有重要价值。     

在体3.0 T MR波谱的肝脏脂质含量多元线性逐步回归模型

目的 采用在体3.0 T MRS方法筛选出影响肝脏脂质沉积的重要因素并建立回归预测方程.方法 正常及弥漫性脂肪肝志愿者共44名,记录身高、年龄、体质量及体质量指数(BMI),采用3.0 T超导MR扫描仪,8通道腹部相控阵线圈,行单体素点分辨波谱分析法序列采集.采集前行常规预扫描,记录线宽(LW)及抑水率(WS),所获谱线采用后处理软件分析.以水为内参照,对肝脏的脂肪含量进行标准化,定义为脂(%)=脂/(脂+水)×100%.对身高、体质量、年龄、BMI、LW、WS和肝脏标准化脂质含量采用Person方法进行相关分析,以肝脏中脂质含量为因变量进行多元线性回归,采用逐步回归方法建立预测方程.结果 受试者肝脏脂质含量(0.00～0.96%,中位数为0.02%)与年龄[(39.1±12.6)岁]、体质量[(64.4±10.4)kg]、BMI(23.3±3.1)、LW(18.9±4.4)及WS[(90.7±6.5)%]5个因素的表达有相关性(r值分别为0.11、0.44、0.40、0.52和-0.73,P值均<0.05),只有年龄、BMI、LW及WS进入多元线性回归方程.预测方程标准化脂质含量(Y)=1.395-(0.021×WS)+(0.022×BMI)+(0.014×LW)-(0.004×年龄),决定系数为0.61,校正决定系数为0.59.结论 该回归模型拟合较好,自变量年龄、BMI、LW及WS能够解释约60%肝脏脂质含量的变化.     

~(31)P MR波谱在犬顿抑心肌实验中的应用

目的　评价 3 1PMRS在犬顿抑心肌研究中的应用价值。方法　 10条健康杂种犬开胸阻断左冠状动脉前降支 2 0min后 ,解除阻断予以再灌注 ,分别在术前、术后 2、4、6、8h ,1、2、3、12d不同时间点进行心肌3 1PMRS的动态检测。结果　正常对照组结果显示 ,心肌组织磷酸肌酸 /β -三磷酸腺苷 (PCr/β -ATP)和无机磷酸盐 /磷酸肌酸 (Pi/PCr)的比值分别是 1.70± 0 .6 1与 0 .2 0± 0 .0 8,pH值为 7.19± 0 .2 0。顿抑心肌再灌注后 2h ,PCr/β -ATP和 pH值下降 (Ρ <0 .0 5 ) ,Pi/PCr比值提高 (Ρ <0 .0 1) ;PCr/β -ATP在再灌注后 4h时接近正常 ,之后无明显差异 ;而Pi/PCr比值上升持续到再灌注后第 3d ,在第 12d恢复至正常水平。pH值在再灌注后 6～ 8h逐渐恢复正常。结论　心肌缺血再灌注后 ,Pi/PCr比值的变化能较早且准确地反映心肌的代谢状态 ,为临床早期诊断顿抑心肌提供了一种无创性连续观测的新方法。     

在体肝脏3.0T1H-MR波谱匀场及抑水影响因素探讨

目的 探讨受检者的自身因素对在体肝脏1H-MRS自动预扫描中匀场和抑水效果的影响.方法 回顾性分析57例行肝脏1H-MRS检查受检者资料,其中正常受检者35名、慢性乙型肝炎5例、脂肪肝14例、脂肪肝合并慢性乙型肝炎3例.把受检者按是否抑水率(WS)≥90%及是否匀场线宽(LW)20 Hz分别分为2组,分别采用两独立样本的t检验比较2组的一般情况如身高、体重、体质量指数(BMI),采用卡方检验比较脂肪肝组与非脂肪肝组达到较好的LW和WS效果的比率.结果 抑水较好组47例和抑水不好组10例比较,平均身高[分别为(164.7±8.0)和(170.5±3.7)cm]、体重[分别为(61.8±10.4)和(73.4±5.4)kg]、BMI[分别为(22.7±3.2)和(25.2±1.3)kg/m2]及LW[分别为(17.7±3.7)和(24.6±6.3)Hz],差异均有统计学意义(t值分别为-3.488、-3.415、-4.002和-3.327,P值均<0.05).匀场较好组41例和匀场不好组16例比较,体重[分别为(62.2±11.6)和(68.1±6.1)kg],BMI[分别为(22.8±3.4)和(24.2±1.9)kg/m2],WS[分别为(93.0±2.7)%和(86.1±8.5)%],差异均有统计学意义(t值分别为-2.516、-2.024和3.213,P值均<0.05).脂肪肝组17例中,7例自动匀场LW≤20 Hz,无脂肪肝组40例中,34例自动匀场LW≤20 Hz,2组间差异有统计学意义(X2=11.347,P<0.05).脂肪肝组17例中,WS<90%者7例,无脂肪肝组40例中,无WS<90%患者,两者差异有统计学意义(X2=28.536,P<0.05).结论 肝脏的脂质沉积对1H-MRS匀场及抑水存在负性影响,体重及BMI大的受检者达到良好的匀场和抑水效果预期成功率低.     

肝脏肿瘤的活体氢质子MR波谱和病理分析

目的 研究活体肝脏氢质子MRS(1H-MRS)评价肝脏局灶性病变的价值.方法 对53例肝肿瘤患者(54个直径＞4 cm的肿瘤)和19名正常志愿者进行1H-MRS检查,分别测量满足诊断需要的正常对照组(17名)和经病理证实的良性肝脏肿瘤组(8例)和肝细胞癌(HCC)组(25例)胆碱I唪/甘油三酯亚甲基峰(Cho/Lip)比值,对结果进行方差分析和两样本间Dunnett-t检验,并通过受试者工作特征(ROC)曲线评价1H-MRS诊断HCC的敏感性和特异性.结果 正常肝脏、良性肿瘤及HCC组的Cho/Lip比值分别为0.07±0.04、0.11±0.06和0.55±0.17(F=6.58,P＜0.05),HCC组高于正常对照组和良性肝脏肿瘤组(t值分别为2.99和2.32,P值均＜0.05),正常肝脏组和良性肿瘤组Cho/Lip比值差异无统计学意义(t=1.53,P＞0.05).ROC曲线下面积为0.77,1H-MRS对诊断HCC有较高诊断价值,当Cho峰与Lip峰比值界值点为0.1时,诊断HCC的敏感性和特异性分别为80.0%和62.5%.结论肝脏局灶性病变1H-MRS分析是可行的,对于鉴别IHCC和良性肝脏肿瘤有一定的临床参考价值.     

在体肝脏3.0T1H-MR波谱匀场及抑水影响因素探讨

Objective To characterize the clinical factors which influence water suppression and auto-shimming line width for liver 3.0 T 1H-MRS.Methods Fifty-seven cases with liver 1H-MR spectroscopy(1H-MRS) were retrospectively studied, including chronic type B hepatitis (n=5), fatty liver (n=14), chronic type B hepatitis combining fatty liver (n=3) and normal situation (n=35).Independent t test was used to characterize the difference of general condition (height, weight, body mass index etc.) between different water suppression effect groups and between different shimming effect groups.Using Chi-square test to analyze whether water suppression rate and auto-shimming line width between fatty liver groups and non-fatty liver exist significance difference .Results By comparing WS ≥90% (n=47)group with WS < 90% (n=10) group, the former showed smaller average height[(164.7±8.0) and (170.5±3.7) cm respectively], weight[(61.8±10.4) and (73.4±5.4) kg respectively], BMI [(22.7±3.2) and (25.2±1.3)kg/m2 respectively]and LW[(17.7±3.7)and(24.6±6.3) Hz respectively]than the latter (t=-3.488,-3.415,-4.002 and-3.327, P < 0.05).By comparing LW 20 Hz (n=41) group with LW 20 Hz (n=16) group, the former showed better water suppression rate [(93.0±2.7)% and (86.1±8.5)% respectively]than the latter(t=3.213,P <0.05), whereas larger weight[(62.2±11.6) and (68.1±6.1)kg respectively]and BMI[(22.8±3.4) and (24.2±1.9)kg/m2 respectively](t=-2.516,-2.024,P <0.05).LW≤20 Hz in the fatty liver and non-fatty liver group was 7/17 and 34/40, respectively (X2=11.347, P < 0.05).WS < 90% in the fatty liver and non-fatty liver group was 10/17 and 0/44, respectively (X2=28.536, P < 0.05) .Conclusion Hepatic steatosis exerts an adverse effect in water suppression and shimming.     

在体肝脏3.0T1H-MR波谱匀场及抑水影响因素探讨

Objective To characterize the clinical factors which influence water suppression and auto-shimming line width for liver 3.0 T 1H-MRS.Methods Fifty-seven cases with liver 1H-MR spectroscopy(1H-MRS) were retrospectively studied, including chronic type B hepatitis (n=5), fatty liver (n=14), chronic type B hepatitis combining fatty liver (n=3) and normal situation (n=35).Independent t test was used to characterize the difference of general condition (height, weight, body mass index etc.) between different water suppression effect groups and between different shimming effect groups.Using Chi-square test to analyze whether water suppression rate and auto-shimming line width between fatty liver groups and non-fatty liver exist significance difference .Results By comparing WS ≥90% (n=47)group with WS < 90% (n=10) group, the former showed smaller average height[(164.7±8.0) and (170.5±3.7) cm respectively], weight[(61.8±10.4) and (73.4±5.4) kg respectively], BMI [(22.7±3.2) and (25.2±1.3)kg/m2 respectively]and LW[(17.7±3.7)and(24.6±6.3) Hz respectively]than the latter (t=-3.488,-3.415,-4.002 and-3.327, P < 0.05).By comparing LW 20 Hz (n=41) group with LW 20 Hz (n=16) group, the former showed better water suppression rate [(93.0±2.7)% and (86.1±8.5)% respectively]than the latter(t=3.213,P <0.05), whereas larger weight[(62.2±11.6) and (68.1±6.1)kg respectively]and BMI[(22.8±3.4) and (24.2±1.9)kg/m2 respectively](t=-2.516,-2.024,P <0.05).LW≤20 Hz in the fatty liver and non-fatty liver group was 7/17 and 34/40, respectively (X2=11.347, P < 0.05).WS < 90% in the fatty liver and non-fatty liver group was 10/17 and 0/44, respectively (X2=28.536, P < 0.05) .Conclusion Hepatic steatosis exerts an adverse effect in water suppression and shimming.     

在体肝脏3.0T1H-MR波谱匀场及抑水影响因素探讨

Objective To characterize the clinical factors which influence water suppression and auto-shimming line width for liver 3.0 T 1H-MRS.Methods Fifty-seven cases with liver 1H-MR spectroscopy(1H-MRS) were retrospectively studied, including chronic type B hepatitis (n=5), fatty liver (n=14), chronic type B hepatitis combining fatty liver (n=3) and normal situation (n=35).Independent t test was used to characterize the difference of general condition (height, weight, body mass index etc.) between different water suppression effect groups and between different shimming effect groups.Using Chi-square test to analyze whether water suppression rate and auto-shimming line width between fatty liver groups and non-fatty liver exist significance difference .Results By comparing WS ≥90% (n=47)group with WS < 90% (n=10) group, the former showed smaller average height[(164.7±8.0) and (170.5±3.7) cm respectively], weight[(61.8±10.4) and (73.4±5.4) kg respectively], BMI [(22.7±3.2) and (25.2±1.3)kg/m2 respectively]and LW[(17.7±3.7)and(24.6±6.3) Hz respectively]than the latter (t=-3.488,-3.415,-4.002 and-3.327, P < 0.05).By comparing LW 20 Hz (n=41) group with LW 20 Hz (n=16) group, the former showed better water suppression rate [(93.0±2.7)% and (86.1±8.5)% respectively]than the latter(t=3.213,P <0.05), whereas larger weight[(62.2±11.6) and (68.1±6.1)kg respectively]and BMI[(22.8±3.4) and (24.2±1.9)kg/m2 respectively](t=-2.516,-2.024,P <0.05).LW≤20 Hz in the fatty liver and non-fatty liver group was 7/17 and 34/40, respectively (X2=11.347, P < 0.05).WS < 90% in the fatty liver and non-fatty liver group was 10/17 and 0/44, respectively (X2=28.536, P < 0.05) .Conclusion Hepatic steatosis exerts an adverse effect in water suppression and shimming.     

在体肝脏3.0T1H-MR波谱匀场及抑水影响因素探讨

Objective To characterize the clinical factors which influence water suppression and auto-shimming line width for liver 3.0 T 1H-MRS.Methods Fifty-seven cases with liver 1H-MR spectroscopy(1H-MRS) were retrospectively studied, including chronic type B hepatitis (n=5), fatty liver (n=14), chronic type B hepatitis combining fatty liver (n=3) and normal situation (n=35).Independent t test was used to characterize the difference of general condition (height, weight, body mass index etc.) between different water suppression effect groups and between different shimming effect groups.Using Chi-square test to analyze whether water suppression rate and auto-shimming line width between fatty liver groups and non-fatty liver exist significance difference .Results By comparing WS ≥90% (n=47)group with WS < 90% (n=10) group, the former showed smaller average height[(164.7±8.0) and (170.5±3.7) cm respectively], weight[(61.8±10.4) and (73.4±5.4) kg respectively], BMI [(22.7±3.2) and (25.2±1.3)kg/m2 respectively]and LW[(17.7±3.7)and(24.6±6.3) Hz respectively]than the latter (t=-3.488,-3.415,-4.002 and-3.327, P < 0.05).By comparing LW 20 Hz (n=41) group with LW 20 Hz (n=16) group, the former showed better water suppression rate [(93.0±2.7)% and (86.1±8.5)% respectively]than the latter(t=3.213,P <0.05), whereas larger weight[(62.2±11.6) and (68.1±6.1)kg respectively]and BMI[(22.8±3.4) and (24.2±1.9)kg/m2 respectively](t=-2.516,-2.024,P <0.05).LW≤20 Hz in the fatty liver and non-fatty liver group was 7/17 and 34/40, respectively (X2=11.347, P < 0.05).WS < 90% in the fatty liver and non-fatty liver group was 10/17 and 0/44, respectively (X2=28.536, P < 0.05) .Conclusion Hepatic steatosis exerts an adverse effect in water suppression and shimming.     

串联线圈大鼠MR成像的初步应用研究

目的 探讨串联线圈进行大鼠3.0 T MR扫描的效果.方法 应用研制的串联线圈与随机所配的3个线圈,分别对自制的水溶液模型运用相同的快速恢复快速自旋回波序列(FRFSE-XL)进行扫描,选择4组图像中同一位置的层面,采用单幅图像测量信噪比(SNR).12只SD大鼠平均分为3个模型组和1个正常组.运用FRFSE-XL序列、快速扰相梯度回波(FSPGR)和多体素波谱(Probe-SI)序列,分别对大鼠脑损伤、脑氢质子MR波谱(1H-MRS)、脊髓损伤(SCI)和大鼠腹部进行了初步应用研究.结果 串联线圈的SNR(39.7)比随机所配的3个线圈中SNR(6.41)最好的膝关节线圈高出6倍以上.大鼠颅脑损伤的T2WI和T1WI能清楚分辨灰质和白质,很好地显示脑室的结构和血肿的位置及大小.注射6-羟基多巴胺(6-OHDA)2周后,大鼠脑部1H-MRS能显示氮-乙酰天冬氨酸/肌酸(NAA/Cr)的比值减小(注射6-OHDA前为1.240,注射2周后为0.781).大鼠胸髓T2WI可清楚显示卵圆形的脊髓,显示"H"形脊髓白质;大鼠SCI模型T2WI清楚显示大鼠胸部脊髓损伤的部位和程度.大鼠腹部扫描,FSPGR序列T1WI时间为8 s,有利于克服呼吸等运动的影响,清楚显示大鼠腹部的结构.结论 应用3.0 T MR结合串联线圈为活体大鼠模型的MR检查提供了很好的方法.     

MR单体素波谱和化学位移成像在颞叶癫痫中的研究

目的　应用MR氢质子波谱 (1HMRS)不同成像方法 ,包括单体素波谱 (SVS)、化学位移成像 (CSI) ,探讨1HMRS对颞叶癫痫 (TLE)的诊断价值。方法　设对照组 4 0例、颞叶癫痫组 (TLE) 2 0例。应用1HMRS分别进行海马结构 (HF)的SVS和CSI,应用SVS比较TLE患侧组、对侧组及对照组各代谢物比值 ,并行致痫灶定侧诊断。应用CSI分析TLE患侧组、对侧组及对照组HF从前到后各体素氮 乙酰天门冬氨酸 / (胆碱 肌酸复合物 ) [NAA/ (Cho Cr) ]的变化规律 ,并进行三组间、各体素间两两比较。结果　SVS示TLE组患侧组HF的NAA/ (Cho Cr) (0 4 8± 0 10 )、NAA/Cr(1 2 0± 0 19)下降 ,与对照组、对侧组 (分别为 0 71± 0 0 7、1 4 8± 0 16 ;0 6 1± 0 12、1 4 4± 0 2 3)差异有显著性意义 (F值分别为 4 1 95 8、15 5 75 ,P值 <0 0 0 0 1)。SVS对TLE定侧敏感度为 85 % ,特异度为 93%。CSI示对照组、TLE患侧、对侧组HF的NAA/ (Cho Cr)与HF部位间呈直线相关关系 ,后部较前部大 ;与正常组比较 ,患侧组前部NAA/ (Cho Cr)的降低程度较后部大。结论　SVS可帮助TLE致痫灶定侧。CSI显示HF从前到后存在NAA/ (Cho Cr)渐变现象 ,TLE患侧头部代谢改变较尾部大。在比较代谢改变时 ,保证定位于HF的相同部位很重要。     

Quantitative P-31 MR spectroscopy of the liver in alcoholic cirrhosis.

To determine the cause of reduced urea synthesis in cirrhosis, absolute concentrations of phosphorus metabolites in the human liver have been measured in vivo with magnetic resonance (MR) spectroscopy. One-dimensional chemical shift imaging was used to obtain phosphorus-31 spectra from five healthy volunteers and five patients with alcoholic cirrhosis. A reference standard included in all studies enabled the calculation of absolute concentrations. In contrast to hepatic metabolite ratios, absolute concentrations reveal that in the cirrhotic patients, concentrations of adenosine triphosphate (ATP) were significantly reduced and concentrations of phosphomonoesters slightly reduced. Intracellular pH was unchanged. Histologic evidence suggests that the amount of ATP per cell was unchanged and could not account for the reduced urea production. Instead, urea synthesis depends on the functional liver cell mass, which was reduced by 31% in alcoholic cirrhosis. Quantitative in vivo P-31 MR spectroscopy of liver has potential clinical applications and can supplement the more generally used P-31 metabolite ratios.     

大鼠肝癌模型LAC-BSA-SPIO增强MR成像研究

目的：探讨LAC-BSA-SPIO对检出肝脏病灶,尤其是微小病灶的潜在价值及其对病灶良恶性鉴别诊断的价值。方法：建立大鼠肝硬化肝癌模型,分别测试LAC-BSA-SPIO最佳注射剂量和最佳扫描时间。28只大鼠MRI平扫序列为SET2map、FSET2WI、SET1WI、FRFSET2WI、GRE、3DFIESTA、SWI,注射LAC-BSA-SPIO（50μmolFe/kg）后30min行增强扫描。结果：成功建立大鼠肝硬化肝癌模型28只,共检出≥2mm的病灶63个,包括36个为肝细胞癌（HCC）,19个腺瘤性增生结节（AHN）,8个炎症性肌纤维母细胞瘤（IMT）。CNR最高的是50μmolFe/kgLAC-BSA-SPIO组;CNR最高的是30min组。增强扫描后AHN、IMT和HCC之间的T2值差异有显著性意义（P〈0.05）。SNR下降最明显的依次是GRE、3DFIESTA、FSET2WI、FRFSET2WI。在所有的序列上,HCC、AHN、IMT增强扫描前后的CNR差异均有显著性意义,所有序列增强扫描前后的差值在HCC、AHN、IMT之间差异有显著性意义（P〈0.05）。结论：LAC-BSA-SPIO有助于提高肿瘤-肝脏的CNR,对于肝硬化性肝癌的病灶有较高的鉴别诊断价值;最佳剂量为50μmolFe/kg,最佳扫描时间为静脉注射后30min。     

DWI和~1H-MRS在肝纤维化中的诊断价值

目的:探讨扩散加权成像(DWI)与氢质子波谱分析(1 H-MRS)在肝纤维化中的诊断价值。方法:使用腹腔注射CCl4溶液法诱导建立兔肝纤维化模型并进行DWI和1 H-MRS检查。DWI使用SE-EPI序列(b1=0s/mm2,b2=600s/mm2),1 H-MRS使用单体素点分辨波谱分析(PRESS)序列(TR 1500ms,TE 35ms),测量表观扩散系数(ADC)值及胆碱(Cho)和脂质(lipid)波峰下面积的比值(Cho/lipid)。以病理学肝纤维化分期为基础,将兔划分为无肝纤维化组(S0)、轻度-中度纤维化组(S1-S2)和重度纤维化及肝硬化组(S3-S4),比较不同组间ADC值和Cho/lipid变化规律。结果:随肝纤维化程度加重,ADC值依次降低(P<0.01),Cho/lipid依次升高(P<0.05);重度纤维化及肝硬化组与另两组ADC值及Cho/lipid差异均具有统计学意义(P均<0.05)。结论:DWI和1 H-MRS具备一定的定量肝纤维化及检测重度纤维化及肝硬化的能力。     

在体肝脏单体素3.0T质子MR波谱采集参数优化研究

目的 探讨质子MR波谱(~1H-MRS)采集参数,包括线圈类型、TE、信号采集次数(NSA)及感兴趣容积(VOI)大小对在体肝脏预扫描匀场、抑水、谱线信噪比(SNR)及基线稳定性的影响.方法 使用GE Signa Excite HD 3.0 T超导MR扫描仪对46名受检者进行检查,采用8通道相控阵线圈和内置体线圈.每名受检者行1～6次不等的单体素点分辨波谱(PRESS)序列~1H-MRS采集,共得到169条谱线.每名受检者首次使用参数均为TR 1500 ms、TE 30 ms、NSA 64次、VOI 2 cm×2 cm×2 cm及8通道相控阵线圈(首次采用的参数记为A);然后利用扫描操作界面的复制功能,复制首次扫描及定位参数,确保波谱采集位置一致,改变下列参数之一,线圈类型、TE、NSA及VOI重复采集(改变后的参数记为B).对水峰的半高全宽(FWHM)、抑水率(WS)、基线稳定性、SNR的每对(A与B)数据评分进行比较,A好于B记为1分,A与B相似记为0分,A差于B记为-1分.对获得的数据统计采用配对样本符号秩和检验.结果 8通道相控阵线圈(A)较体线圈(B)所获谱线(n=11)SNR高(-1分0对,0分1对,1分10对,Z=-3.162,P=0.002),而FWHM较大(-1分8对,0分2对,1分1对,Z=-2.511,P=0.012).TE为30 ms(A)时较TE 90 ms(B)所获谱线(n=13)SNR高(-1分2对,0分0对,1分11对,Z=-2.496,P=0.013),但是基线稳定性差(-1分10对,0分2对,1分1对,Z=-2.333,P=0.020).VOI为2 cm×2 cm×3 cm(B)时较VOI为2 cm×2 cm×2 cm(A)所获谱线(n=10)SNR高(-1分6对,0分4对,1分0对,Z=-2.449,P=0.014),但是FWHM较大(-1分0对,0分5对,1分5对,Z=-2.041,P=0.041).NSA为128次(B)时较NSA为64次(A)所获谱线(n=29)SNR高(-1分21对,0分7对,1分1对,Z=-4.264,P=0.000).结论 在体肝脏单体素3.0 T ~1H-MRS采集时,推荐使用VOI为2 cm×2 cm×3 cm、NSA为128次.体线圈及更小的VOI能达到更好的预扫描匀场效果,增加NSA及增加VOI有助于提高谱线SNR,更长地TE有助于改善不稳定的基线.     

肝硬化患者脑基底节区MRI与MR波谱成像研究

目的利用MRI及MR波谱成像（MRS）研究肝硬化患者是否伴发帕金森综合征的基底节区信号与代谢特征。方法27例肝硬化患者进行MRI与基底节区MRS扫描，其中14例肝硬化患者伴发帕金森综合征。采集N-乙酰天冬氨酸（NAA）、肌醇（mI）、肌酸．磷酸肌酸（Cr）及胆碱复合物（Cho），分别计算NAA／Cr、ml／Cr及Cho／Cr的相对值。18名年龄匹配的健康志愿者作对比。结果27例肝硬化患者伴与未伴帕金森综合征组与正常对照组间的NAA／Cr的平均值分别为1．35±0、03、1．40±0．03、1、44±0．01差异无统计学意义（t值分别为1、16与0．87，P值均〉0．05）。13例未伴帕金森综合征组与正常对照组间苍白球的高信号强度值的平均值分别为1．04±0、003，1．03±0、002，ml／Cr平均值分别为0．63±0．01、0．61±0．02；Cho／Cr的平均值分别为0．82±0．03、0．80±0．02，差异无统计学意义（t值分别为0．63、-0．52、-0．54，P值均〉0．05）。14例伴有与13例不伴有帕金森综合征组间苍白球的高信号强度值平均值分别为1、18±0．001，1．04±0．003，ml／Cr平均值分别为0．39±0．02、0．63±0．01；与Cho／Cr的平均值分别为0．68±0．01，0、82±0．03，差异有统计学意义（t值分别为-5．16、7．61、4、12，P值均〈0．01）。肝硬化患者高信号强度值与ml／Cr（r=-0．764，P〈0．05）及Cho／Cr（r=-0．553，P〈0．05）间呈负相关。结论基底节区MRI与MRS对判断肝性脑病锥体外系受损有重要的临床意义。     

化学位移成像及MR波谱分析在体外水脂模型中对脂肪定量的研究

目的 评价化学位移成像(chemical shift imaging,CSI)和MRS两种方法在脂肪研究中的作用,为进一步活体实验提供定量标准.方法 在7.0 T MR成像仪上运用CSI和MRS方法对体外水脂模型进行水脂定量分析.体外水脂模型的脂肪含量从0～100%平均分成11个组,各组间浓度相差10%,分别应用水、脂肪选择性CSI和1H-MRS对体外水脂模型进行图像和波谱数据采集,对2种方法所得结果分别与实际水脂含量进行单样本t检验及相关分析并比较两种方法问的相关性.MRS计算100%油模型饱和脂肪酸(fraction of saturated fatty acids,FS)、不饱和脂肪酸(fraction of unsaturated fatty acids,FU)的相对含量及多聚不饱和程度(polyunsaturation degree,PUD).结果 CSI法测定实际脂肪含量为50%～100%的测量值分别为(48.0±1.0)%、(57.0±0.5)%、(67.3±0.6)%、(77.3 ±0.6)%、(83.3±0.6)%和(91.0±1.0)%;MRS测定实际脂肪含量为10%～60%的测量值分别为(8.3±0.6)%、(16.3±0.7)%、(27.7±0.6)%、(36.0±1.0)%、(43.5±0.6)%和(56.5±1.0)%,均轻度低估了脂肪含量,差异均有统计学意义(P值均<0.05).CSI与MRS计算的脂肪含量与实际脂肪含量间均呈线性相关(CSI:r=0.998,MRS:r=0.996;P值均<0.01);两种方法间也呈线性相关(r=0.992,P<0.01),两种方法定量脂肪含量差异无统计学意义(t=-0.125,P:0.903).MRS计算橄榄油的FS和FU相对含量分别为0.15和0.85,PUD为0.0325,与实际含量一致.结论 在7.0 T MR成像仪上,体外水脂模型证实CSI和MRS定量脂肪的准确性及在脂肪研究上的可行性.     

Mapping of liver fat with triple-echo gradient echo imaging: validation against 3.0-T proton MR spectroscopy

The purpose of this study was to validate a magnetic resonance imaging (MRI) technique for mapping liver fat, using ¹H magnetic resonance spectroscopy (¹H-MRS) as the reference standard. In 91 patients with type 2 diabetes, 3.0-T single-voxel point-resolved ¹H-MRS was used to calculate the liver fat fraction (LFF) from the water (4.76 ppm) and methylene (1.33 ppm) peaks, corrected for T1 and T2 decays. LFF (corrected for T1 and T2* decays) was also obtained from the mean signal intensity on a map built from a triple-echo (consecutive in-phase, opposed-phase, and in-phase echo times) breath-hold gradient echo sequence, using basic image calculation functions (arithmetic mean, subtraction, division, multiplication by a numerical factor). Mean LFF was 8.9% (range, 0.9–33.5) by MRI and 8.8% (range, 0–34.1) by ¹H-MRS. Pearson’s coefficient was 0.976 (P < 0.0001) and Lin’s coefficient was 0.975 (P < 0.0001). Liver segment had no significant influence. With Bland–Altman analysis, 95.6% (87/91) of data points were within the limits of agreement. Given its excellent agreement with ¹H-MRS, our mapping technique can be used for visual and quantitative evaluation of liver fat in everyday practice.