RT Journal Article
SR Electronic
T1 Kinetic Analysis of <sup>125</sup>I-Iodorotenone as a Deposited Myocardial Flow Tracer: Comparison with <sup>99m</sup>Tc-Sestamibi
JF Journal of Nuclear Medicine
JO J Nucl Med
FD Society of Nuclear Medicine
SP 272
OP 281
VO 42
IS 2
A1 Robert C. Marshall
A1 Patricia Powers-Risius
A1 Bryan W. Reutter
A1 Scott E. Taylor
A1 Henry F. VanBrocklin
A1 Ronald H. Huesman
A1 Thomas F. Budinger
YR 2001
UL http://jnm.snmjournals.org/content/42/2/272.abstract
AB The goal of this investigation was to assess the accuracy of 7′-Z-[125I]iodorotenone (125I-iodorotenone) as a new deposited myocardial flow tracer and compare the results with those for 99mTc-sestamibi. Methods: The kinetics of these two flow tracers were evaluated in 25 isolated, erythrocyte- and albumin-perfused rabbit hearts over a flow range relevant to patients. The two flow tracers and a vascular reference tracer (131I-albumin) were introduced simultaneously as a compact bolus through a port just above the aortic cannula in the absence of tracer recirculation. Myocardial extraction, retention, washout, and uptake parameters were computed from the venous outflow curves using the multiple-indicator dilution technique and spectral analysis. Results: The extraction of 125I-iodorotenone was much higher than the extraction of 99mTc-sestamibi (0.84 ± 0.05 vs. 0.48 ± 0.10, respectively, P &lt; 0.001). 125I-iodorotenone extraction was also less affected by flow than was 99mTc-sestamibi (P &lt; 0.001). Net retention of 125I-iodorotenone was significantly greater than 99mTc-sestamibi net retention at 1 min (0.77 ± 0.08 vs. 0.41 ± 0.11, respectively, P &lt; 0.001) and 26 min (0.46 ± 0.13 vs. 0.27 ± 0.11, respectively, P &lt; 0.001) after tracer injection. Flow had less effect on 125I-iodorotenone net retention than on 99mTc-sestamibi net retention 1 min after tracer injection (P &lt; 0.04). However, at 26 min, flow had an equivalent effect on the retention of both flow tracers (P &lt; 0.4). The relationship between 125I-iodorotenone and 99mTc-sestamibi washout was complex and depended on elapsed time after isotope introduction and perfusion rate. Reflecting the favorable extraction and retention characteristics of 125I-iodorotenone, both its maximum myocardial uptake and its 26-min uptake were more closely related to flow than were those of 99mTc-sestamibi (P &lt; 0.001 for both comparisons). Conclusion: The extraction and retention of 125I-iodorotenone were greater than those of 99mTc-sestamibi, making 125I-iodorotenone the superior flow tracer in the isolated rabbit heart.