Blood flow-metabolism imaging with positron emission tomography in patients with diabetes mellitus for the assessment of reversible left ventricular contractile dysfunction

OBJECTIVES The purpose of this study was to evaluate the predictive accurac y of positron emission tomography (PET) blood flow-F-18 fluorodeoxyglucose (FDG) imaging in coronary artery disease (CAD) patients with diabetes melli tus (DM). BACKGROUND Positron emission tomography accurately predicts the postrevascu larization improvement in left ventricular dysfunction in unselected patien ts with CAD. In diabetic patients, however, poor myocardial glucose utiliza tion may limit the accuracy of the approach. METHODS Forty patients (64 +/- 10 years old; 19 with DM =,group I; 21 witho ut DM = group II) with reduced left ventricular ejection fraction (LVEF = 2 9 +/- 6%) were studied with N-13 ammonia and FDG PET before coronary revasc ularization. Studies were performed after intravenous injection of regular insulin (group I) or oral glucose administration (group II). Blood flow-FDG mismatches and matches were identified by polar map analysis in the three vascular territories of the left anterior descending, left circumflex and r ight coronary artery. Wall motion and LVEF were assessed by two-dimensional echocardiography before and 158 +/- 123 days after revascularization. RESULTS Of 107 vascular territories analyzed, 46 were classified as mismatc h, 29 as match and 32 as normal. The FDG image quality, assessed by F-18 my ocardium to blood pool activity ratios, and the predictive accuracy were si milar in both groups; presence of a blood flow/FDG mismatch had a sensitivi ty of 92% (group I) and 94%, (group II) and a specificity of 85% (group I) and 79% (group II) for an improvement in regional left ventricular function . A postrevascularization improvement in global left ventricular function w as related to the extent of blood flow/FDG mismatch; LVEF increased from 30 +/- 7% to 35 +/- 7% (p = 0.017) in patients with one mismatch and from 27 +/- 4% to 41 +/- 7% (p < 0.001) in those with two mismatches. CONCLUSIONS The predictive accuracy of blood flow/FDG imaging is maintained in patients with DM when a clinically acceptable study protocol, which gua rantees good FDG image quality, is used. The extent of a blood flow/metabol ism mismatch is correlated with the magnitude of the postrevascularization improvement in global left ventricular function. (C) 1999 by the American C ollege of Cardiology.