American Media Inc is currently on issue no. 46 of volume 18.
Volume typically refers to the number of years the publication has been circulated, and issue refers to how many times that periodical has been published during that year. For example, the April 2011 publication of a monthly magazine first published in 2002 would be listed as, "volume 10, issue 4".
https://en.m.wikipedia.org/wiki/Periodical_literature