In comparison, the 2016 edition of the RSNA meeting had 48,888 advance registrants. In the key category of professional attendees, 23,097 individuals registered in advance this year, down slightly from 23,656 advance registrants in 2016.
In a post on its website, the RSNA said the figures were "in line with our expectations." The society said that audited registration numbers will be available in early January.
Final attendance figures should be somewhat higher than the advance registration numbers; in 2016, for example, the RSNA reported 54,037 total attendees and 26,988 professional attendees.