Coronary artery wall echogenicity increases on echocardiograms during the acute phase of Kawasaki disease (KD). According to this background, echogenicity of the coronary artery wall in patients with KD is quantified by using integrated backscatter (IB) analysis.IB analysis is a quantitative method for evaluating echogenicity. We examined the value of IB in the wall of the left anterior descending coronary artery and compared it with that in adjacent intracardiac blood as a measure of background. The difference between these values is represented as corrected IB for the coronary artery wall.Corrected IB for the coronary artery wall was higher in patients with KD than in controls (KD with pre-immunoglobulin therapy vs. controls: 27.4 ± 5.3 dB vs. 22.0 ± 3.5 dB, P < .05) and in patients with coronary enlargement after intravenous immunoglobulin (with vs. without coronary enlargement, 29.2 ± 5.2 dB vs. 24.1 ± 5.5 dB, P < .05).The magnitude of IB from the coronary artery wall reflects the effectiveness of immunoglobulin therapy. Furthermore, this method and its value might be useful to predict the occurrence of coronary enlargement in patients with KD.