[Left ventricular asynergy detected by cardiac blood pool emission computed tomography using the subtraction method]

To evaluate left ventricular regional wall motion, ECG dual-gated cardiac blood pool ECT was performed for 25 patients with ischemic heart disease, including 19 cases of myocardial infarction, five cases of angina pectoris, and one case of post A-C bypass surgery. There were six normal controls. Following SPECT obtained using 32 views (180 degrees), the vertical and horizontal long axes were reconstructed from transaxial images. Then, regional wall motion was evaluated from subtraction images; (end-diastolic)-(end-systolic) and (end-systolic)-(end-diastolic) images. SPECT images were compared with left ventriculography (LVG); vertical long-axial ECT images with segments 1-5 of LVG by the AHA classification, and horizontal ECT long-axial images with segments 6 and 7 of LVG, respectively. The subtraction images from ECG dual-gated cardiac blood pool ECT corresponded with left ventriculography in 79.4% of 175 segments in 25 patients with ischemic heart disease (sensitivity 92.6%, specificity 68.0%, and accuracy 79.4%). When wall motion was classified as normal, hypokinesis, akinesis, and aneurysmal, good agreement was observed between the two methods in 68% of these segments. The locations of asynergy as obtained by this method were closely in accord with those of perfusion defects by Tl-201 myocardial SPECT in 74.4% of segments. Left ventricular aneurysms were detected using subtraction image; (end-systolic)-(end-diastolic). We conclude that this subtraction method is useful for evaluating left ventricular asynergy.