Simultaneous evaluation of fatty acid metabolism and myocardial flow in an explanted heart.
The biodistribution of the fatty acid analog [131I]PHIPA 3-10, was compared to the flow tracer 99mTc-sestamibi by quantitative analysis in a dual-isotope study performed during a heart transplantation.


METHODS
Iodine-131-PHIPA 3-10 and 99mTc-sestamibi were injected simultaneously approximately 20 min prior to the start of surgical procedure. Scintigraphic images of the sliced explanted heart were compared to the preoperative in vivo scans using [123I]PHIPA 3-10, 201TI and 99mTc-sestamibi. In 14 tissue samples of the explanted heart, the radioactive contents from [131I]PHIPA 3-10 and 99mTc-sestamibi were calculated as %ID/g-values and correlated with the corresponding histology.


RESULTS
In the preoperative scans, a mismatch of fatty acid uptake and perfusion ([123I]PHIPA 3-10 > flow) was observed which indicated residual viable myocardium, while a matched defect was associated with scar. In viable myocardium, there was a significantly higher accumulation of [131I]PHIPA 3-10 compared to 99mTc-sestamibi (mean 5.9 x 10(-3) versus 2.7 x 10(-3)%ID/g),whereas in scars the uptake of both tracers was comparable (1.2 x 10(-3) versus 1.4 x 10(-3)%ID/g).


CONCLUSIONS
Myocardial viability can be defined more accurately with radioiodinated PHIPA 3-10 than with 99mTc-sestamibi. The differences of biodistribution in viable myocardium and scars indicate that not only perfusion but also the metabolic state of the myocardium can be evaluated with radioiodinated PHIPA 3-10.
Jonas
M
M
Department of Nuclear Medicine, Westfälische Wilhelms University of Münster, Germany.
Brandau
W
W
Vollet
B
B
Weyand
M
M
Fahrenkamp
A
A
Gildehaus
F J
FJ
Sciuk
J
J
Scheld
H H
HH
Schober
O
O
D003326:Coronary Circulation; D006207:Half-Life; D006321:Heart / Q000000981:diagnostic imaging*; D016027:Heart Transplantation; D006801:Humans; D066298:In Vitro Techniques; D008297:Male; D008875:Middle Aged; D009206:Myocardium / Q000473:pathology; D010666:Phenylpropionates / Q000493:pharmacokinetics; D011877:Radionuclide Imaging; D017256:Technetium Tc 99m Sestamibi / Q000493:pharmacokinetics; D013794:Thallium Radioisotopes
C102993:4-(10-(4-iodophenyl)decyl)benzenepropanoic acid; D010666:Phenylpropionates; D013794:Thallium Radioisotopes; D017256:Technetium Tc 99m Sestamibi