The purpose of this study was to clarify the relationship between TKE derived from 4D Flow MRI and LVOT gradient measured by US in the patients with HOCM. We recruited 3 volunteers, and 10 patients who were diagnosed as HOCM by cardiac ultrasound examination. The TKEsum and TKEpeak of HOCM group were higher than those of volunteers (107.0±25.0mJ vs. 39.2±8.7mJ, p=0.025; 15.5±3.8mJ vs. 4.1±0.6mJ, p=0.025). There was no significant correlation between each two TKE value and LOVT gradient (p=0.203, p=0.556, respectively). The TKE can clearly reveal the flow characteristics of HOCM and may provide different value form established US measurement.