The prevalence and natural history of hepatic cysts examined by ultrasound: a health checkup population retrospective cohort study oleh Kota Tsuruya, Yasuhiro Nishizaki, Masayuki Tatemichi, Yusuke Mishima, Yoshimasa Shimma, Yoshitaka Arase, Shunji Hirose, Koichi Shiraishi, Tatehiro Kagawa