X 线视频密度仪计算左心室射血分数

Estimation of left ventricular ejection fraction(EF)by videodensitometry

为检验 X 线视频密度仪计算左心室射血分数的准确性,17例冠心病患者接受了数字减影左室造影。ADAC 数字减影系统可描记左室密度一时间曲线,并可用面积长度公式计算左心室容量。密度法和面积长度公式计算的射血分数进行了相关和对照。结果表明,两法计算的射血分数高度相关,r=0.93,P<0.001。为进一步了解两法射血分数的动态关系,从收缩期开始,每34毫秒记录一次密度值,计算一次左室容量。然后代入公式求得连续射血分数。结果显示,长度面积公式计算的射血分数上升较密度法早而快。结论:X 线视频密度仪可以准确地计算射血分数,但密度值与造影剂的厚度并不呈紧密的线性关系。

Digital subtraction left ventriculograms were obtained in 17 patients.The ventriculograms were analyzed by videodensitometry(VIDEO),and density-time curves were constructed.EF was obtained by subtracting the density values of end-systole from that of end-diastole,and dividing the difference by the latter density value.Correlation was made between EFs by VIDEO and area- length methods.The correlation coefficient was 0.93,P<0.001.The serial EFs by these two me- thods were plotted as the function of systolic interval.The results showed that the serial EFs by the area-length method rose ealier and faster than the serial EFs by VIDEO.It is concluded that EF can be accurately measured by VIDEO.However,several physical factors may prevent X-ray attenuation from being linearly proportional to the depth of iodine contrast.