Tc-99m-sestamibi retention characteristics during pharmacologic hyperemia in human myocardium: Comparison with coronary flow reserve measured by Doppler flowire
J. Taki et al., Tc-99m-sestamibi retention characteristics during pharmacologic hyperemia in human myocardium: Comparison with coronary flow reserve measured by Doppler flowire, J NUCL MED, 42(10), 2001, pp. 1457-1463
Citations number
32
Categorie Soggetti
Radiology ,Nuclear Medicine & Imaging","Medical Research Diagnosis & Treatment
The aim of the study was to investigate the increase in myocardial Tc-99m-m
ethoxyisobutylisonitrile (sestamibi) retention in humans during pharmacolog
ic vasodilation. Methods: For calculation of the increase in Tc-99m-sestami
bi retention during hyperemia, baseline and adenosine triphosphate (ATP)-in
duced hyperemic stress sestamibi studies were performed using a same-day re
st-stress protocol. On the injection of sestamibi, left ventricular dynamic
data were obtained for 90 s. The increase in sestamibi retention from base
line to hyperemia was calculated by the formula
Cm-h(t) integral (t)(0) Cb-b(tau )d tau /Cm-b(t) integral (t)(0) Cb-b(tau )
d tau,
where CMh(t) and CMb(t) are myocardial counts on the tomographic image, and
Cb-b(tau) and Cb-h(tau) are the left ventricular blood-pool counts during
the first transit of sestamibi at baseline and during hyperemia, respective
ly. Coronary flow increase during intravenous ATP stress was measured using
intracoronary Doppler flow guide wire and compared with the scintigraphic
results of 28 measurements in 22 patients. Results: Sestamibi retention inc
reased as coronary flow velocity increased but plateaued at >2.5-3 times ba
seline flow velocity. The relationship between the increase in sestamibi re
tention (Y) and the increase in flow (X) is expressed as follows: Y = 0.44
+ 0.60X - 0.068X(2) (r = 0.82). Conclusion: In humans, the increase in Tc-9
9m-sestamibi myocardial retention underestimates coronary flow reserve, par
ticularly at high flow rates. Knowledge of these tracer retention character
istics will contribute to a more comprehensive understanding of the manner
and interpretation of stress sestamibi imaging.