心肌磁共振显像、核素心肌灌注显像和超声心动图测定左心功能的对比研究

Assessment of left ventricular function: comparison of cardiac MR imaging, electrocardiogram-gated SPECT and echocardiography

目的评价心肌磁共振显像(MRI)、门控核素心肌灌注显像(SPECT)和超声心动图(Echo)检测急性心肌梗死(AMI)患者左心室功能的应用价值。方法AMI患者23例,分别于一周内行MRI、SPECT及Echo三项检查,测定左室舒张末期容积(EDV)、收缩末期容积(ESV)和射血分数(EF),将MRI检测结果作为标准,并与SPECT及Echo结果比较,行相关分析及一致性检验。结果MRI采用多层Simpson法,图像空间分辨率高,可以准确划分血池和心肌的界限。SPECT较MRI低估左室容积EDV15.9ml,ESV8.3ml,EF值两者大致相等。Echo较MRI低估左室容积EDV53.2ml,ESV33.0ml,高估EF5.3%。经相关分析,SPECT与MRI所测EDV、ESV、EF相关系数分别为0.79、0.84、0.84(P均<0.001),Echo与MRI所测EDV、ESV、EF相关系数分别为0.54(P<0.01)、0.43(P<0.05)、0.63(P<0.01)。经Bland-Altman一致性检验,SPECT与MRI所测左室容积及射血分数有等价性。结论MRI检测心功能准确、可靠。SPECT与MRI具有等价性。Echo左心功能测值较MRI有明显偏倚,需进一步改进检测方法以提高准确性。

Objective To evaluate accuracy of electrocardiogram-gated single-photon emission computed tomography （SPECT） and echocardiography （Echo） for assessment of left ventricular function comparing with cardiac magnetic resonance imaging. Methods MRI, SPECT and Echo were performed in 23 patients with the onset of acute myocardial infarction （AMI）within one week. End-diastolic volume （EDV）, end-systolic volume （ESV）, and ejection fraction （EF） were estimated with SPECT and Echo. The result of which was compared with the gold standard of cardiac MRI. Statistical evaluation of correlation and agreement were assessed. Results Muhislice Simpson＇s method were used by MRI. Cardiac MRI provides excellent spatial resolution, and can easily define the border of blood pool and myocardium. Left ventricular volumes were underestimated [EDV （15.9±27.1） ml, ESV （8.3±20.6） ml] using SPECT compared with MRI. Average EF value is approximately the same. Left ventricular volumes were underestimated [EDV （15.9±27.1） ml, ESV （8.3±20.6） ml] using echocardiography compared with MRI, and overestimated EF by 5.3%. The correlation between SPECT and MRI for EDV, ESV, EF were 0.79, 0.84, 0.84, respectively （P〈0. 001）. The correlation between Echo and MRI were 0.54 （P〈 0.01）, 0.43 （P〈0.05） , 0.63 （P〈0.01）. Bland-Ahman analysis indicated that the left ventricular volume and EF between SPECT and MRI was in agreement. Conclusion MRI is reliable and shows a high degree of accuracy in measuring cardiac function. SPECT and MRI are agreement in measuring cardiac function. However, the value in measuring left ventricular function is deviated by using Echo, thus making it necessary to improve this measuring method to enhance accuracy.