Factors influencing accuracy in left ventricular volume determination.
The accuracy with which left ventricular volume is determined from contrast ventriculograms depends on the care with which the analysis protocol is followed. Therefore, the effect of variations in the method used for calculating the correction factor (CF) that adjusts for magnification and image distortion on volume calculation was measured. The results showed that error in the CF is caused by (in order of decreasing importance): filming the calibration figure at a different magnification mode from that of the ventriculogram, at a different height from the table than the level of the ventricle, or with the image intensifier at a different height than used during ventriculography; use of a calibration figure less than half the size of the ventricle; calculation of the CF from only 1 band pair of a banded catheter; or placement of the calibration figure at the periphery rather than the center of the imaging field. Error in volume determination was proportional to error in the CF. With care, the error in volume can be reduced to that due to interobserver variability in tracing the endocardial contours.
Cardiovascular Research and Training Center, University of Washington, Seattle 98195.
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Sheehan
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Mitten-Lewis
D002138:Calibration; D002933:Cineradiography / Q000592:standards*; D006321:Heart / Q000000981:diagnostic imaging*; D006439:Hemodynamics; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000592:standards*; D009200:Myocardial Contraction