Evaluation of dilated cardiomyopathy by stress Tl-201 myocardial single photon emission computed tomography (SPECT)

Stress Tl-201 myocardial SPECT was performed in 20 dilated cardiomyopathy (DCM) and 23 old myocardial infarction (OMI: ED volume ≥ 200 ml by left ventriculography = LVG) for non-invasive diagnosis of DCM. We assessed the perfusion abnormality of 5 segments (anterior-anterolateral, septal, apical, posterolateral, postero-inferior) in SPECT images in grades as follows; 0: normal, 1: mild low uptake, 2: severe low uptake, 3: complete defect. Thus, we defined the abnormal perfusion score (APS) as the summation of the grades in 5 segments. 1) Perfusion abnormality was found 85 % in DCM and 100 % in OMI by stress SPECT images. 2) Rare complete defect, abnormal perfusion segments under 3 and APS under 7 were characteristic findings in DCM, and could finally distinguish DCM from OMI with the finding of APS under 7 (18/20: 90 %) in stress images. 3) The perfusion abnormality in delayed images had a good relation with wall motion abnormality in OMI, but not DCM. 4) Redistribution was found only 3 cases with DCM (15 %) and 9 cases with OMI (39 %), but mild without 2 cases with OMI. 5) Inspite of exercise induced severe symptom and arrhythmia in some DCM cases, stress SPECT was efficient especially to rule out ischemic heart disease. Thus, we conclude that stress Tl-201 myocardial SPECT is useful method for the non-invasive differential diagnosis of DCM from ischemic heart disease, but wall motion abnormality has no good relation with perfusion abnormality. (author)