J. Taki et al., Forward cardiac output measurement with first-pass technique using Tc-99m-labeled myocardial perfusion imaging agents, J NUCL MED, 40(11), 1999, pp. 1874-1881
Citations number
27
Categorie Soggetti
Radiology ,Nuclear Medicine & Imaging","Medical Research Diagnosis & Treatment
The aim of this study was to develop and validate a new first-pass method f
or the measurement of forward cardiac output (CO) using Tc-99m-labeled myoc
ardial perfusion imaging agents. Methods: In protocol 1, to test the new me
thod for measuring CO, the conventional method and the new method for CO me
asurement were performed in 1 d in 57 patients (32 men, 25 women; age 68 +/
- 11 y). In the conventional method, radionuclide angiography (1 frame/s) w
ith in vivo Tc-99m labeling (110 MBq) of red blood cells was performed for
2 min in the left anterior oblique projection. Five minutes later, a 1-min
equilibrium image was obtained, and a blood sample was taken for calculatio
n of the distribution volume. To obtain data for the new method, further ra
dionuclide angiography (1 frame/sec) with 99mTc labeling (600-740 MBq) of r
ed blood cells was then performed in the anterior projection. CO was calcul
ated using the following equation:
CO = C-max x V-LV/integral f(t)dt.
where C-max is the background-corrected peak count of the whole thorax duri
ng angiography, integral f(t)dt is the area under the gamma variate-fitted
left ventricular (LV) time-activity curve after background correction and V
-LV is the LV volume obtained by the area length method applied to the radi
onuclide angiography and myocardial tomography In protocol 2, to evaluate t
he new method, 24 patients (16 men, 8 women; age 71 +/- 9.2 y) underwent ra
dionuclide angiography with Tc-99m-tetrofosmin (600-740 MBq), and the measu
red CO was compared with the CO obtained by the conventional method with Tc
-99m-labeled red blood cells. Results: In protocol 1, good correlation was
observed between the CO by the new method (Y) and the CO by the conventiona
l method (X): Y = 1.0X + 57 mL/min and r = 0.95. There was good agreement b
etween the two methods (mean difference -56 +/- 381 mL/min). Inter- and int
raobserver correlation coefficients were 0.96 and 0.98, respectively. In pr
otocol 2, the CO by the new method using 99mTc-tetrofosmin (Y) showed a goo
d correlation with the CO by the conventional method (X): Y = 0.90X + 453 m
L/min and r = 0.93. Good agreement between the two methods was observed (me
an difference 73 +/- 390 mL/min), Inter- and intraobserver correlation coef
ficients were 0.95 and 0.98, respectively. Conclusion: This new method perm
its accu- rate forward CO measurement using the first-pass data with Tc-99m
-terofosmin, which is applicable to other Tc-99m-labeled myocardial perfusi
on imaging agents.