Ds. Lee et al., Development of a method for measuring myocardial contractility with gated myocardial SPECT and arterial tonometry, J NUCL CARD, 6(6), 1999, pp. 657-663
Background. Gated myocardial single photon emission computed tomography (SP
ECT) and radial artery applanation tonometry were used, respectively, to qu
antify the time-volume curve of the left ventricle and to estimate ventricu
lar pressure wave, We developed ways of determining end-systolic elastance
(Ees) with the normalized-single-beat method and tested the reproducibility
of these measurements.
Methods and Results. In patients with coronary artery disease (male/female
= 33:2, age 66 +/- 10 years, ejection fraction 22% to 77%), rest thallium-2
01 gated/poststress technetium-99m sestamibi gated SPECT/24-hour rest Tc-99
m sestamibi gated SPECT and arterial tonometry were performed. Quantitative
gated SPECT software yielded a systolic time-volume curve, and tonometrica
lly measured radial artery pressure wave yielded central aortic pressure wa
ve. With systolic half of pressure-volume curve, void volume (Vo) was estim
ated and Ees was calculated. Over 71 measurements Ees ranged from 1.7 to 5.
3 and Vo from -4 to 200 mt. Ejection duration, other indexes of central pre
ssure waveform, end-diastolic volume, end-systolic volume, and ejection fra
ction were reproducible. The reproducibility of Vo was excellent (r = 0.97)
. Ees at rest (n = 15) showed fair reproducibility between Tc-99m-sestamibi
and Tl-201 SPECT (r = 0.51).
Conclusion, With gated myocardial SPECT, a noninvasive method of quantifing
myocardial global contractility was developed. Reproducibility of this mea
surement was sufficient for use in clinical routine. Ees measured by this m
ethod warrants validation by invasively measured Ees.