Factors that affect the reproducibility of measurements of left ventricular function from first-pass radionuclide ventriculograms.

Dymond, D. S.; Elliott, Alex; Stone, David L.; Hendrix, Grady H.; Spurrell, R. A. J.

doi:10.1161/01.cir.65.2.311

Cited by 32 publications

(8 citation statements)

References 38 publications

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“…Mean CPTT and the distribution of CPTT are usually derived from measurements over a 30 s period, using first pass radionuclide cardiography. Centroid and deconvolution methods have been used to calculate mean CPTT and distribution of CPTT, respectively (MacNee et al 1989;Hopkins et al 1996;Capderou et al 1997;Zavorsky et al 2002a,b) with a day-to-day intra-observer error of about 0.28-0.42 s and a correlation coefficient of 0.96 between methods (Dymond et al 1982;Hopkins et al 1996;Zavorsky et al 2002a,b). Relative dispersion (RD = S.D./mean CPTT) can then either be calculated from the variance of the gamma variate fits of the right and left ventricle time-activity curves, or from the variance of the gamma function resulting from the deconvolution process.…”

Section: Methods To Directly Calculate Whole Lung Pulmonary Transit Tmentioning

confidence: 99%

Red Cell Pulmonary Transit Times Through the Healthy Human Lung

Zavorsky

Walley

Russell

2003

Experimental Physiology

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It has previously been postulated that rapid red cell capillary transit through the human lung plays a role in the mechanism of diffusion limitation in some endurance athletes. Methodological limitations currently prevent researchers from directly measuring pulmonary capillary transit times in humans during exercise; however, first pass radionuclide cardiography allows direct measurement of red blood cell (RBC) transit times through the whole lung at various exercise intensities. We examined the relationship between mean whole lung red cell pulmonary transit times (cardiopulmonary transit times or CPTT) and different levels of flow in 88 healthy humans (76 males, 12 females) from several studies (mean age 31 years). The pooled data suggest that the relationship between CPTT and cardiac index (CI), beginning at rest and progressing through to maximum exercise demonstrates that CPTT reaches its minimum value when CI is about 8.1 l m2 min−1 (2.5‐3 times the CI value at rest), and does not significantly change with further increases in CI. Cardiopulmonary blood volume (CPBV) index also does not change significantly until CI reaches 2.5 to 3 times the CI value at rest and then increases roughly linearly after that point. Consequently, the systematic increase in CPBV index with increasing pulmonary blood flow between 8.1 and 20 l m2 min−1 displays an adaptive response of the cardiopulmonary system by augmenting CPBV (and perhaps pulmonary capillary blood volume through distension and recruitment) to offset the reduction in CPTT, as no significant difference in mean CPTT is observed between these levels of flow (P > 0.05). Therefore, these data demonstrate that CPBV does not reach maximum capacity during strenuous or maximum exercise. This does not support the principle of quarter‐power allometric scaling for flow when explaining modifications during exercise. Therefore, we speculate that the observed relationships between CPTT, CBPV index and flow may prevent mean CPTT (and perhaps mean pulmonary capillary transit times) from decreasing below the threshold time required for oxygenation.

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Section: Methods To Directly Calculate Whole Lung Pulmonary Transit Tmentioning

confidence: 99%

Red Cell Pulmonary Transit Times Through the Healthy Human Lung

Zavorsky

Walley

Russell

2003

Experimental Physiology

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“…The variation in the determination of left ventricular depth, which is neces sary to assess the radiation attenuation, was a major source of observer variability in the equilibrium study [11], Whereas a very small mean difference (0.2 li ters/min) was found in the study by Verani et al [11], the standard deviation of the intraobserver variation was also higher (1.0 liters/min) compared with our results (0.34 and 0.48 liters/min for the two observers). Manual left ventricular edge detection and background drawing are the essential sources of error in radionuclide meth ods measuring left ventricular volume and ejection frac tion [12][13][14], The first-passage radionuclide technique for measurement of cardiac output involves a semiauto matic determination of the area under the left ventricu lar time-activity curve [3], whereas the gated equilibrium technique involves left ventricular depth measurement. The latter seems to be a greater potential source of vari ability.…”

Section: Discussionmentioning

confidence: 99%

Variability in First-Passage Radionuclide Cardiac Output: Hour-to-Hour, Day-to-Day, and Observer Variation

Kelbæk¹,

Guørup²,

Aldershvile³

et al. 1988

Am J Noninvas Cardiol

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Sources of variation in cardiac output determined by the first-passage radionuclide technique were evaluated in 30 patients with coronary artery disease. In 12 fasting patients the standard deviations of differences in cardiac output measured three times with 1-hour intervals were 0.77 and 0.93 liters/min. No systematic variation was evident. An 8 % reduction was demonstrated in cardiac output measured in 18 patients at 2-day intervals (p < 0.01), possibly due to anxiety or discomfort at the first examination. The standard deviation of the day-to-day differences was 0.61 liters/min and thus not higher than that of the hour-to-hour differences. The standard deviation of differences between two-observer analysis was 0.34 liters/min, and a small difference of 3.7% was statistically significant (p < 0.05). No significant intraobserver variation was found. Intraobserver differences had standard deviations of 0.34 and 0.48 liters/min. In patients with coronary artery disease, the first-passage radionuclide cardiac output accordingly varies considerably over time, but the precision of this technique is high.

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“…If right ventricular transit is relatively rapid and the number of right ventricular cycles available for analysis is consequently small, these factors may limit statistical accuracy because of low count-rates. Background correction appears to be an important factor in first-pass studies of both right ventricular function (4), and left ventricular function (11). Using the multicrystal gamma camera for left ventricular studies, background correction is per-formed by the use of a single frame subtraction technique.…”

Section: Discussionmentioning

confidence: 99%

“…Relative movement of this line due to alterations in the projection might not be expected to cause large changes in observed counts. In firstpass radionuclide studies of the left ventricle, it has been suggested that changes in calculated ejection fraction with differing projections are due to different efficiencies in detecting scatter and background radiation (11). A further factor is that the right atrial region of interest is smaller than the planar background region of interest, and this combined with minimal atrial overlap in the right anterior oblique projection would tend to increase calculated right ventricular ejection fraction.…”

Section: Discussionmentioning

confidence: 99%

Effects of projection and background correction method upon calculation of right ventricular ejection fraction using first-pass radionuclide angiography

1985

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There is no consensus as to the best projection or correction method for first-pass radionuclide studies of the right ventricle. We assessed the effects of two commonly used projections, 30 degrees right anterior oblique and anterior-posterior, on the calculation of right ventricular ejection fraction. In addition two background correction methods, planar background correction to account for scatter, and right atrial correction to account for right atrio-ventricular overlap were assessed. Two first-pass radionuclide angiograms were performed in 19 subjects, one in each projection, using gold-195m (half-life 30.5 seconds), and each study was analysed using the two methods of correction. Right ventricular ejection fraction was highest using the right anterior oblique projection with right atrial correction 35.6 +/- 12.5% (mean +/- SD), and lowest when using the anterior posterior projection with planar background correction 26.2 +/- 11% (p less than 0.001). The study design allowed assessment of the effects of correction method and projection independently. Correction method appeared to have relatively little effect on right ventricular ejection fraction. Using right atrial correction correlation coefficient (r) between projections was 0.92, and for planar background correction r = 0.76, both p less than 0.001. However, right ventricular ejection fraction was far more dependent upon projection. When the anterior-posterior projection was used calculated right ventricular ejection fraction was much more dependent on correction method (r = 0.65, p = not significant), than using the right anterior oblique projection (r = 0.85, p less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

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Factors that affect the reproducibility of measurements of left ventricular function from first-pass radionuclide ventriculograms.

Cited by 32 publications

References 38 publications

Red Cell Pulmonary Transit Times Through the Healthy Human Lung

Red Cell Pulmonary Transit Times Through the Healthy Human Lung

Variability in First-Passage Radionuclide Cardiac Output: Hour-to-Hour, Day-to-Day, and Observer Variation

Effects of projection and background correction method upon calculation of right ventricular ejection fraction using first-pass radionuclide angiography

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