Observer Variance in the Qualitative Evaluation of Left Ventricular Wall Motion and the Quantitation of Left Ventricular Ejection Fraction Using Rest and Exercise Multigated Blood Pool Imaging
Observer Variance in the Qualitative Evaluation of Left Ventricular Wall Motion and the Quantitation of Left Ventricular Ejection Fraction Using Rest and Exercise Multigated Blood Pool Imaging
复制标题
使用休息和运动多门控血池成像对左心室壁运动定性评估和左心室射血分数定量的观察者方差
作者：
R. Okada;H. Kirshenbaum;F. Kushner;H. Strauss;R. Dinsmore;J. Newell;C. Boucher;P. Block;G. Pohost;W. Shea
静息和运动状态下的多门控血池成像(MBPI)已被广泛应用于评价左室室壁局部运动和射血分数。由于这些测试的精确度取决于观察者间和观察者内的解释差异，我们进行了以下研究。59例患者在静息和仰卧位踏车运动高峰期进行MBPI检查，并在心导管术期间进行静息左心室造影(LVg)。49名患者有明显的冠状动脉疾病，10名患者没有。由3名独立观察者对静息MBPI、运动MBPI和LVG节段性室壁运动进行评分。为了评分的目的，将左室壁细分为前外侧、心尖、下壁、隔壁、心尖下壁和后壁。示踪剂研究和对照研究的室壁运动均以5分制主观评分：3=正常，2=轻度运动减退，1=中度至重度运动减退，0=运动迟缓，−1=运动障碍。射血分数由两个独立的观察者在静息和运动MBPI中六次测定，使用计数技术，允许在感兴趣的区域逐帧变化。射血分数由两个独立的观察者用面积长度法测定三次。结果采用双因素方差分析，用±2标准差表示。使用5分计分系统，根据所分析的室壁，节段性室壁运动评分的观察者间差异估计范围为其余MBPI的0.60至±1.02级，运动MBPI的±0.94至±1.46级，以及LV图的±0.66至±0.98级。节段性室壁运动评分的观察者间差异估计范围为静息和运动MBPL之间的变化，范围为±0.56到±1.08，取决于所分析的室壁。静息MBPI的观察者间变异大于仅隔壁左室壁射血分数的观察者间变异(P<；0.01)。射血分数测定的观察者内和观察者间变异分别为5.8%和±6.0%，运动MBPI的±9.2%和±9.6%，以及静息和运动MBPI之间射血分数变化的±11.0%和±11.4%。当单个观察者两次测定静息和运动MBPI的射血分数，然后将平均静息和平均运动射血分数进行比较时，观察者内方差降至±4.6%。左心室射血分数的观察者内变异为±6.0%，观察者间变异为±11.6%。尽管静息MBPI和左心室射血分数的观察者内方差无显著差异，但静息MBPI射血分数的观察者间方差显著小于LVG(p<；0.005)。静息MBPI节段性室壁运动的观察者间方差，以及静息MBPI射血分数的观察者间和观察者内方差与LV克相当，隔壁除外。这一结果为解释运动引起的左心室局部室壁运动和射血分数的变化提供了客观标准。为了最大限度地减少由于观察者差异造成的误差，运动引起的射血分数的变化应该通过比较至少两次测定的平均射血分数来确定其余的和运动的MBPI。
Multigated blood-pool imaging (MBPI) at rest and with exercise has been widely used for the evaluation of left ventricular regional wall motion and ejection fraction. Because the precision of these tests depends on interobserver and intraobserver variations in interpretation, we performed the following study. Fifty-nine patients had MBPI at rest and during peak supine bicycle exercise and left ventriculography (LV gram) at rest during cardiac catheterization. Forty-nine patients had significant coronary artery disease and 10 did not. Rest MBPI, exercise MBPI and LV gram regional wall motion were graded by three independent observers. For scoring purposes the left ventricular wall was subdivided into anterolateral, apical, inferior, septal, apical-inferior and posterior walls. Wall motion for both the tracer and contrast studies was scored subjectively on a five-point scale: 3 = normal, 2 = mild hypokinesis, 1 = moderate-to-severe hypokinesis, 0 = akinesis, −1 = dyskinesis. Ejection fraction was determined by two independent observers six times for both rest and exercise MBPI using a counts technique that allowed frame-by-frame variations in the regions of interest. Ejection fraction was determined by two independent observers three times for the LV gram using an area-length method. Results were analyzed by a two-way analysis of variance and expressed as ± 2 SD. Using the five-point scoring system, the estimated interobserver variance for regional wall motion scores ranged from 0.60 to ± 1.02 grade for the rest MBPI, ± 0.94 to ± 1.46 grade for the exercise MBPI, and ± 0.66 to ± 0.98 grade for the LV gram, depending on the wall analyzed. The estimated interobserver variance for regional wall motion scores ranged from ± 0.56 to ± 1.08 grade for a change between rest and exercise MBPls, depending on the wall analyzed. Interobserver variance for the rest MBPI was greater than that for the LV gram for only the septal wall (p < 0.01).Intraobserver and interobserver variance for ejection fraction determinations were 5.8% and ± 6.0%, respectively, for the rest MBPI, ± 9.2% and ± 9.6% for the exercise MBPI and ± 11.0% and ± 11.4% for a change in ejection fraction between rest and exercise MBPIs. When a single observer determined the ejection fraction twice for both the rest and the exercise MBPI, and then compared the averaged rest with the averaged exercise ejection fraction, the intraobserver variance was reduced to ± 4.6%. Intraobserver and interobserver variance for the LV gram ejection fraction were ± 6.0% and ± 11.6%. Although intraobserver variance for the rest MBPI and LV gram ejection fraction were not significantly different, interobserver variance for the rest MBPI ejection fraction was significantly less than that for the LV gram (p < 0.005).Interobserver variance for rest MBPI regional wall motion, and interobserver and intraobserver variance for rest MBPI ejection fraction are comparable to those for the LV gram, except for the septal wall. The results offer objective criteria by which exercise-induced changes in left ventricular regional wall motion and ejection fraction can be interpreted. To minimize the error due to observer variance, exercise-induced changes in ejection fraction should be determined by comparing averaged ejection fractions derived from at least two determinations for both the rest and the exercise MBPI.