Decreased uptake of iodinated branched fatty acid analog indicates metabolic alterations in ischemic myocardium.
We previously reported that uptake of 123I-labeled 15-iodophenyl 3-methyl pentadecanoic acid (BMIPP) was lower than that of thallium in ischemic myocardium. Such discordant findings between BMIPP and thallium were compared with those of PET using 18F-deoxyglucose (FDG) and 11C-acetate to assess metabolic alterations in such segment.


METHODS
Sixteen patients with coronary artery disease underwent both BMIPP SPECT and PET. Relative FDG uptake (% FDG uptake) and the clearance rate constant (% Kmono) of 11C-acetate from the myocardium were calculated as markers of glucose and oxidative metabolism, respectively.


RESULTS
Relative FDG uptake of the myocardial segments with reduced BMIPP uptake and normal thallium uptake (discordant segments) was similar (85.3 +/- 10.3) to that of the normal segments (86.5 +/- 11.7) but higher than that of segments with reduced uptake of both BMIPP and thallium (67.5 +/- 19.9). Similarly, the discordant segments showed a higher % Kmono value (77.8 +/- 13.1 versus 70.0 +/- 19.1) and FDG-to-perfusion ratio (1.15 +/- 0.08 versus 1.01 +/- 0.22) than in the concordantly reduced segments.


CONCLUSIONS
BMIPP uptake appears to provide metabolic information independent of thallium uptake. Combined imaging of BMIPP and thallium may potentially identify ischemic but viable myocardium.
D000085:Acetates; D002250:Carbon Radioisotopes; D003327:Coronary Disease / Q000000981:diagnostic imaging*; D003652:Decanoic Acids / Q000493:pharmacokinetics; D003847:Deoxyglucose / Q000031:analogs & derivatives; D005227:Fatty Acids; D005260:Female; D005462:Fluorine Radioisotopes; D019788:Fluorodeoxyglucose F18; D006321:Heart / Q000000981:diagnostic imaging*; D006801:Humans; D007457:Iodine Radioisotopes; D007462:Iodobenzenes / Q000493:pharmacokinetics; D008297:Male; D008875:Middle Aged; D009206:Myocardium / Q000378:metabolism*; D013794:Thallium Radioisotopes; D014055:Tomography, Emission-Computed; D015899:Tomography, Emission-Computed, Single-Photon
D000085:Acetates; D002250:Carbon Radioisotopes; D003652:Decanoic Acids; D005227:Fatty Acids; D005462:Fluorine Radioisotopes; D007457:Iodine Radioisotopes; D007462:Iodobenzenes; D013794:Thallium Radioisotopes; C049338:iodofiltic acid; D019788:Fluorodeoxyglucose F18; D003847:Deoxyglucose