High-energy FLASH frames destroyed bubbles every 15 cardiac cycles, and resultant time-intensity curves derived from these sequences were fitted to an exponential function as y = A(1-e -bt )+c from which the rate of signal rise (b) was obtained.

• 每 15个心动周期进行 1次破泡。 破泡后的再充盈时间 -强度关系可用公式y =A(1-e-bt) +c表示 ,依此可得到信号增加率b。