a decreasing trendp = 0.348
Overall, delay heart-mediastinum ratio (H/M) had no significant change, and washout rate (WR) showed a decreasing trend (delay H/M; pre 2.07 ± 0.46, post 2.05 ± 0.49, paired p = 0.348, WR; pre 36.1 ± 11.6%, post 33.6 ± 11.7%, paired p = 0.061).