在体^1H-MR波谱心肌甘油三酯含量检测方法的建立和可重复性研究

The establishment and reproducibility of 1^H-MR spectroscopy in the determination of myocardial triglyceride content in vivo

目的建立^1H-MRS心肌细胞内甘油三酯含量（MTC）的检测方法并进行可重复性研究。方法经常规体检后选取10名健康志愿者，在呼吸门控和心电门控下获得四腔心和短轴面图像以准确定位室间隔，将ROI设定在收缩末期室间隔，应用点分辨波谱（PRESS）序列在呼气末收缩末期由心电图R波激发采集波谱信号，MTC以脂峰下面积与水峰下面积的百分比表示，3个月后重复进行心脏。H—MRS检查以验证该方法的可重复性，以配对t检验比较3个月前后MTC的差异，采用两个变量之间相关性分析MTC和临床特征之间的相关性。结果健康志愿者MTC含量约为（0．46±0．17）％，3个月后（0．48±0．19）％，差异无统计学意义（t=-0．569，P=0．583），MTC和人体学特征如体质量指数[BMI（21．1±2．1）kg／m2，r=0．271，P=0．449]、腰围[（77．9±4．7）cm，r=0．105，P=0．772]、腰臀比（WHR0．81±0．01，r=0．172，P=0．635）、收缩压[SBP（111±16）mmHg（1mmHg=0．133kPa），r=0．267，P=0．456]、舒张压[DBP（71±9）mmHg，r=0．553，P=0．097]，空腹血糖[FPG（4．77±0．44）mmol／L，r=0．568，P=0．087]、总胆固醇[TC（4．25±0.55）mmol／L，r=0.067，P=0.854]、甘油三酯[TG（1.07±0.48）mmol／L，r=n478，P=0.162]之间均没有相关性。结论 ^1H-MRS可定量检测心肌细胞内甘油三酯含量，该方法重复性好，可用于临床研究。

Objective To establish the method of 1H-MRS in the determination of myocardial triglyceride content （MTC） in vivo and test its reproducibility. Methods Ten healthy volunteers were recruited after routine physical examination. Cardiac images of the four-chamber and short axis views were collected. Spectroscopic volumes of interest were positioned within the interventricular septum on the endsystolic images. PRESS sequence spectroscopic data acquisition was triggered by electrocardiograph-derived R wave and synchronized with respiratory cycle at end-exhalation. MTC was calculated by the ratio of areas of resonances for lipid and water. After three months 1H-MRS of the heart were conducted again to investigate the reproducibility of the method. MTC before and after three months was compared by using paired t test. The correlation between MTC and clinical data was determined by using correlation analysis. Results MTC in healthy volunteers were （ 0. 46 ±0. 17 ） % and （ 0. 48 ± 0. 19 ） % for the baseline and follow-up respectively. No difference was identified （ t = - 0. 569, P = 0. 583 ）. MTC was not correlated with body mass index [ BMI （21.1 ± 2. 1 ） kg/m2, r = 0. 271, P = 0. 4491 , waist circumference [ （ 77.9 ± 4. 7） cm,r = 0. 105,P = 0. 772J, walst-to-hip ratio （ WHR 0. 81 ± 0. 01 ,r = 0. 172,P = 0. 635）, systolic blood pressure [ SBP（ 111 ± 16） mm Hg （ 1 mm Hg = 0. 133 kPa）, r = 0. 267, P = 0. 456 ], diastolic blood pressure [ DBP（71±9） mm Hg,r = -0. 553 ,P = 0. 097], fasting glucose [ FPG（4. 77 ±0.44） mmol/L, r=0.568,P=0.087], total cholesterol [TC（4.25 ± 0.55） mmol/L,r = 0.067, P = 0.854] and triglyceride [TG （1.07±0.48） mmoL/L,r= 0.478,P = 0. 1621. Conclusions Myocardial triglyceride content can be quantitatively determined by 1H-MRS. The reproducibility of myocardial 1H-MRS was good for clinical purpose.