A new scintigraphic method for determining left ventricular volumes.

Abstract

A new scintigraphic count-based method for measuring absolute left ventricular volumes is presented. It is a fast and simple technique that allows geometrical assumptions to be avoided and is free of radiation attenuation corrections. This method requires the acquisition of an image of the left ventricle in the right anterior oblique projection and the collection of gated blood pool images in the left anterior oblique projection. To assess the accuracy of the method scintigraphic stroke volumes were compared with those derived from thermodilution measurements during cardiac catheterization in 20 subjects, and to assess its precision the technique was applied to phantom data of known radionuclide volumes. Excellent correlations were found between the scintigraphic and both the thermodilution (r = .98) and phantom data (r = .99). The reproducibility (r = .97) of results was investigated by repeating data acquisition and analysis for 15 subjects on two different days, and the interobserver variability (r = .97) of the method was studied by having two computer operators calculate volumes for the same patient data for 20 randomly selected studies. Circulation 70, No. 4, 672-680, 1984. SEVERAL METHODS have been reported for estimating left ventricular volumes with the use of scintigraphic data and all of these come under the general categories of geometric or count-based methods. Geometric methods such as the Dodge-Sandler approximation1' 2 are convenient in that they do not require any information in addition to gated equilibrium data in one view, but have the disadvantage of not taking into account the variety of shapes of the ventricular chamber.3 Also, these geometric techniques are not particularly well suited to the analysis of scintigraphic data since the resolution of the boundaries of the ventricular walls is poorer than for contrast angiocardiographic chambers,9 "0 while others require removal, processing, and counting of blood samples after the gated equilibrium studies.9-Means of correcting for attenuation by placing a source within the patient's esophogus have been implemented,'2 but may not gain wide acceptance because of the inconvenience to the patient. Aside from the additional time and effort on the part of technologists that these methods require, they can yield inaccurate results in children and in obese patients, as evidenced by the wide range of average attenuation coefficients obtained by these methods.'2The

Validation of Gated Blood-Pool SPECT Regional Left Ventricular Function Measurements

“…The calculation of EF is fully count-based and-unlike echocardiography, ventriculography, and perfusion imaging-does not depend on geometric assumptions of ventricular shape (8). Because counts are attenuated equally in diastole and systole, attenuation has a negligible effect on EFs in planar multigated radionuclide angiography (MUGA) data (19). This negligible effect should apply equally to global and regional EFs determined from tomographic MUGA studies.…”

Routine measurements of left and right ventricular output by gated blood pool emission tomography in comparison with thermodilution measurements: a preliminary study

“…Tomographic multi-gated angiography has potential in evaluating right and left ventricular volumes. Total ventricular output at equilibrium can be derived from these measurements as the product of stroke volume and heart rate [15,16,17,18,19,20,21,22,23,24]. From a clinical point of view, end-diastolic and end-systolic volumes are at least as pertinent as cardiac output, but the validation of such volume measurements is difficult because of the lack of a gold standard.…”

“…Thus, it may permit simultaneous assessment at equilibrium of the right and left ventricular ejection fractions and volumes, the regurgitant fraction and regional wall motion (including the use of phase analysis for the identification of atrio-ventricular nodal bypass tracks) [13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28]. Recently, software dedicated to the segmentation of TRVG data has been developed and validated clinically, making possible the widespread use of this technique in clinical settings [29,30,31].…”

Menopause-Related Changes in Left Ventricular Function in Healthy Women

“…Two views of the heart were obtained at rest: a left anterior oblique view providing the best septal separation, and a left posterior oblique view, orthogonal to the former. Enddiastolic volumes were determined using a modi fied version of the method of Nichols et al [5]. The count/ml/s constant was obtained from the enddias tolic volume previously recorded and left ventricular counts.…”