Chen J, Garcia E V, Henneman M M, Bax J J, Boogers M J, Trimble M A, Borges-Neto S, Velazquez E J, Iskandrian A E
Department of Radiology, Emory University, Atlanta, GA 30322, USA.
Minerva Cardioangiol. 2008 Apr;56(2):227-35.
Cardiac resynchronization therapy (CRT) has shown benefits in patients with severe heart failure. The traditional criteria to select patients for CRT (New York Heart Association [NYHA] class III or IV, depressed left ventricular [LV] ejection fraction, and prolonged QRS duration) result in at least 30% of the selected patients with no response to CRT. Recent studies with echocardiography have shown that the presence of LV dyssynchrony is an important predictor for response to CRT. However, the recent report from the predictors of response to cardiac resynchronization therapy (PROSPECT) trial suggested that under ''real-world'' conditions the current available echocardiographic techniques including tissue Doppler imaging (TDI) and myocardial strain-rate imaging are not ready for routine clinical practice to assess LV dyssynchrony. Phase analysis is a recently developed technique that allows measuring LV dyssynchrony from electrocardiogram (ECG)-gated single photon emission computed tomography (GSPECT) myocardial perfusion imaging (MPI). This technique uses Fourier harmonic functions to approximate regional wall thickening over the cardiac cycle and to calculate regional onset of mechanical contraction (OMC) phases. These OMC phases are obtained three-dimensionally over the entire left ventricle to quantitatively assess the degree of LV dyssynchrony. This technique has been compared to TDI and shown promising results in clinical validations. The advantages of this technique over echocardiography in measuring LV dyssynchrony are its automation, its high repeatability and reproducibility. It can be applied to any conventional GSPECT MPI study with no additional procedure. In this review the phase analysis methodology is described and its up-to-date clinical validations are summarized.
心脏再同步治疗（CRT）已在重度心力衰竭患者中显示出益处。选择CRT治疗患者的传统标准（纽约心脏协会[NYHA] III或IV级、左心室[LV]射血分数降低以及QRS时限延长）导致至少30%的入选患者对CRT无反应。近期的超声心动图研究表明，LV不同步的存在是CRT反应的重要预测指标。然而，心脏再同步治疗反应预测因子（PROSPECT）试验的最新报告表明，在“现实世界”条件下，包括组织多普勒成像（TDI）和心肌应变率成像在内的当前可用超声心动图技术尚未准备好用于评估LV不同步的常规临床实践。相位分析是一种最近开发的技术，它可以从心电图（ECG）门控单光子发射计算机断层扫描（GSPECT）心肌灌注成像（MPI）中测量LV不同步。该技术使用傅里叶谐波函数来近似心动周期中的区域心肌增厚，并计算机械收缩起始（OMC）阶段。这些OMC阶段是在整个左心室三维获取的，以定量评估LV不同步的程度。该技术已与TDI进行比较，并在临床验证中显示出有前景的结果。该技术在测量LV不同步方面优于超声心动图的优点在于其自动化、高重复性和再现性。它可以应用于任何常规GSPECT MPI研究，无需额外操作。在这篇综述中，描述了相位分析方法并总结了其最新的临床验证情况。
