How can I add session user_id to: admin settings -> add item menu -> path field?

Hi guys,

In the link: http://dev/cec/?q=en/admin/build/menu
I edited the "My Blog" secondary link and in the path field I wanted to enter something like this:
blog/[user-id]
or something like
blog/$_SESSION['user_id']

But I don't know how to add a dynamic current session user_id variable. Is it possible?

Thanks in advance.

Cheers,
Mark