Useful Method of Low-dose Dobutamine Quantitative Gated SPECT in Kawasaki Disease with Severe Coronary Arterial Lesion

Abstract

Quantitative gated SPECT (QGS)is useful imaging for the myocardial perfusion and left ventricular function. To assess simultaneously myocardial perfusion and left ventricular contractile reserve by Low-dose Dobutamine(LDD) QGS in Kawasaki disease, we studied in 19 patients with severe coronary arterial lesions including myocardial infarction (group C, mean 15.9, 5-23 year old), and 15 patients without coronary stenotic lesion (group N, mean 10.4, 3-19 year old). Technetium-99m tetrofosmin (Tf) was injected into vein at ergometer or ATP stress, and at rest on the same day. Low-dose Dobutamine (3-5 μg/kg/min) was started after Tf injection at rest. Comparison of wall motion abnormality (WMA) by QGS and myocardial perfusion image from non-gated SPECT was obtained. In this method, the myocardial contractile reserve evaluated post-stress image and LDD image simultaneously on the myocardial perfusion evaluation in respect of stress image and resting image. Results: Left ventricular ejection fraction by post-stress QGS was 59.4±5.9% of group C, 69.6±8.1% of group N (p<0.01), and by LDD QGS was 69.3±7.9% and 78.3±9.1%, respectively (p<0.01). The diagnosis of myocardial viability in group C was 26% in the myocardial perfusion evaluation, 89% in the improvement of WMA through LDD. Nine percent disclosed palpitation, but the other side effect was not recognized in this method. Conclusions: LDD QGS is useful and safety method for the evaluation of myocardial contractile reserve in addition to the conventional myocardial perfusion image. This method improves the diagnosis of myocardial viability in kawasaki disease with myocardial infarction.