Radionuclide techniques for evaluating dilated cardiomyopathy and ischemiccardiomyopathy

Objective To assess the clinical significance of radionuclide techniques in evaluating dilated cardiomyopathy (DCM) and ischemic cardiomyopathy (CAD-C M). Methods 28 patients with DCM and 55 patients with CAD-CM were studied. All patients underwent Tc-99m-MIBI myocardial perfusion SPECT and (18F)-FDG myo cardial metabolic PET. 78 patients had Tc-99m-RBC radionuclide ventriculogr aphy and 68 patients had coronary angiography. Results The results of 23 patients (82%) with DCM showed mild and non-segme ntal distribution perfusion abnormalities. 52 patients with CAD-CM (95%) sh owed perfusion abnormalities that distributed along the coronary vessel ter ritories. Significant perfusion defects were found in 4 patients with DCM ( 14%) and 45 patients with CAD-CM (82%) (P < 0.01). The average perfusion sc ore was 4.5 +/- 2.6 in DCM and 9.6 +/- 2.5 in CAD-CM and the area of dimini shed perfusion was significantly smaller in DCM than in CAD-CM (P < 0.001). Two patients with DCM and 18 patients with CAD-CM had metabolic defects. T he patterns of perfusion/metabolic imaging showed mismatch in most patients with CAD-CM but match in most patients with DCM. The LVEF in patients with DCM and CAD-CM was both decreased but the decreases were not statistically different between DCM and CAD-CM. The RVEF in patients with DCM was signif icantly lower than that in patients with CAD-CM (32.4% +/- 13.9% vs 40.9% /- 15.4%, P < 0.05). Conclusion The radionuclide techniques are helpful for distinguishing DCM f rom CAD-CM. The segmental perfusion abnormality and RVEF are the most impor tant factors for differentiation of DCM from CAD-CM.