The article "Usefulness of Hydrogel-Coated Coils in Embolization of Pulmonary Arteriovenous Malformations," written by Masashi Shimohira, Tatsuya Kawai, Takuya Hashizume, Masahiro Muto, Masanori Kitase and Yuta Shibamoto, was originally published electronically on the publisher's Internet portal (currently SpringerLink) on January 17, 2018, without open access.