While using the f12 tools on ie, when I request a web page, the response header has a content type. Can this also be called MIME type? Or is there a difference?
Strictly speaking MIME and content type are two different things. MIME is a set of standards that was written to extend the capabilities of email messages and has since been applied more broadly to internet content and HTTP. Content type is a header used both in email messages and HTTP.
Practically, however, content type and MIME type are used interchangeably.
To answer your question: In your context, there is no difference.