OBJECTIVE: To assess the regional left ventricular systolic function of children with Kawasaki disease before and after treatment by vector myocardial strain and strain rate imaging (VSI) technology. METHODS: The regional left ventricular systolic function was assessed using VSI technology in 32 children with Kawasaki disease before treatment and one month after treatment and in 30 age-matched normal children. RESULTS: Nine segments of the left ventricular in the Kawasaki disease group before treatment had decreased longitudinal peak systolic strain rate (LSRs) compared with the normal control group. After treatment, the LSRs in 9 segments in the Kawasaki disease group increased, but 6 segments had decreased LSRs compared with the normal control group. The radial peak systolic strain rate (RSRs) of 8 segments in the Kawasaki disease group before treatment was lower than that in the control group. After treatment, only one segment had decreased RSRs compared with the control normal group and 5 segments had increased RSRs compared with that before treatment. The circumferential peak systolic velocity (CVs) of 6 segments in the Kawasaki disease group before treatment group was lower than that in the control normal group. After treatment, only one segment had decreased CVs in the Kawasaki disease group compared with the control normal group and 3 segments had increased CVs compared with that before treatment. CONCLUSIONS: The regional left ventricular systolic function in children with Kawasaki disease before and after treatment can be accurately assessed using VSI technology, which shows the clinical significance of this technology in assessment of treatment outcome in children with Kawasaki disease.［Chin J Contemp Pediatr, 2010, 12 (4):248-251］