Right ventricular size and function: The discrepancy between cardiac blood pool imaging techniques

Abstract

The purpose of thls study was to evaluate a number of equlllbrlum radknucllda method. for analydng rlgM wntrkular rlzs utd functlon, In an attempt to dawmhm if m y of a variety of approach8 could .ccumtdy charactorb rlgM ventrkular hamodynamlcr. Fwtiaen patbnb bdng cllnlcrlly ev&mtmd tor eoronwy artery d b m w (N = Q), congestive cardlomyopathy (N = 2), valvular dlseasa (N = 2), or hrtnccvdkc shunts (N = 1) undowent blplae contmst rlgM ventrkulogmphy W M n g gated bkod pool Imaglng. F w r radlonuclide bchnlqucm ware examlmd end Incluckd: (1) a mnkutomatlc edge&ttlon algorithm using a vwkbk dgM wntrlculw rogkn-ot-lnterest and a rlgM wntrkular apical end dk.tolk background; (2) performance; however, validation with conventional contrast angiography has not been performed. The goals of this study were to compare several of these currently available radionuclide methods with biplane constrast right ventriculography and to assess the interobserver and intraobserver variability of each method studied. MATERIALS AND METHODS Patlent PopulatlonFifteen patients who were scheduled to undergo diasnostic cardiac catheterization were studied in a serial fashion. Indications for diagnostic catheterization included an assessment of: ischemic heart disease (N = 10); congestive idiopathic cardiomyopathy (N = 2); aortic stenosis (N = 2); and atrial septal defect (N = 1). None of these patients had historical, clinical, or laboratory findings that suggested pulmonary disease. ProtocolEach patient was prepared in the standard fashion for the cardiac catheterization, and received 10 mg of oral diazepam as premedication. The catheters (a #7 Cournand and #8F NIH) used for evaluation of right ventricular pressure and function were placed through a femoral vein. They remained in the pulmonary artery and the inferior vena cava, respectively, during the radionuclide study. Within 1 hr of completion of the diagnostic catheterization protocol, each patient underwent in vivo red blood cell labeling with 15 mg of stannous pyrophosphate and 15-20 mCi of technetium Wm. A single crystal, gamma scintillation camera (General Electric Porta Data Camera, Milwaukee, Wisconsin), equipped with a high sensitivity parallel hole collimator, was placed in the 45" left anterior oblique projection with slight (< 10") caudal tilt. The camera was equipped with a pulse-height analyzer set at 140 keV with a 20% "window." A modified V-5 electrode was used for EKG gating; the heart rate and rhythm were stable during the study (< 3 extrasystoles per min). Ten minutes of scintigraphic data were collected. Blood samples, for the purpose of ventricular volume determinations, were taken from the right heart catheter.Fifteen minutes following the radionuclide, the 8F NIH catheter was placed into the body of the right ventricle, and biplane cine right ventriculograms were performed (30" RAO and 60" LAO projections). Fifty-five milliliters of meglumine sodium diatriozate (Renografin-76) were injected over a 3-to 4-sec interval into the right ventricular chamber. Cineangiog...

Videodensitometric Determination of Right Ventricular and Left Ventricular Ejection Fraction

“…Inherent differences in spatial resolution of the techniques also may have contributed in part to discrepancies noted. Nonetheless, our results indicate a correlation between radionuclide cineangiographic and intravenous digital contrast ventriculograms which is comparable to those previously reported between radio nuclide angiography and geometrically analyzed conven tional contrast left ventricular cineangiograms [7,10,15], and between radionuclide cineangiographic and bi plane contrast cineangiographic right ventriculograms [16]. Because of the physical proximity of contrast injec tion to the right ventricle, the adequacy of mixing of blood and contrast in the right ventricle initially was considered a potential source of inaccuracy of contrastbased right ventricular determinations.…”

Reproducibility of determination of right ventricular ejection fraction by radionuclide imaging: Assessment by the statistical method of variance components

“…In four studies dealing with the accuracy of RVEF measurements [1,9,12,17], comparisons were made between four different cineangiographic methods, two different first-pass and four different equilibrium methods with no clear preference emerging. Comparisons of first-pass and equilibrium methods are more frequent [4, 6-8, 11, 16, 17], but often difficult to interpret, especially if two methods with each a tendency for underestimation of RVEF are compared in diseased patients [20].…”

“…Several factors, including the gamma camera projection, the equipment used, and the processing of data influence the calculated values. Most studies agree that the camera position is important, and that right atrial and right ventricular overlap is unavoidable in the anterior or LAO view [5,12,20,24]. Various procedures have been suggested to compensate for this, among these, background subtraction by a narrow area in the region of the tricuspid valve plane [2], subtraction of one half of the right atrial counts from the right ventricular counts [13], and definition of right ventricular edges by functional images [6,14], special computer algorithms [11], or from pictures obtained by means of a slant hole collimator [6,8].…”

“…Radionuclide methods for determination of right ventricular ejection fraction (RVEF) vary considerably [1][2][3][4][5][6][7][8][9][10][11], and so do the reported figures on the reliability of these measurements [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17]. Their accuracy is not very well known, because there is no generally accepted reference method applicable in both patients and normal control subjects.…”

“…Their accuracy is not very well known, because there is no generally accepted reference method applicable in both patients and normal control subjects. Another question is whether the variability of these measurements only permits evaluation of group or population data, or whether it is sufficiently low to also allow evaluation of individuals and measurement of small changes in RVEF over time [12,16]. To answer this would require knowledge of the confidence limits of single and repeat measurements, but such data are not available in the literature, although several authors have described various elements of reproducibility with these methods [2-4, 6, 7, 9-171 . It was the aim of the present study to establish confidence limits for determination of RVEF performed by preferential radionuclide methods.…”