A question about the time to evacuate a queen in a master game I am studying a book about chess strategy, and in the chapter concerning the d4,e4 center I have this game:

(PACHMAN, VESELY, Pragues, 1953)

r1b2rk1/pp1nqppp/2pb1n2/4p3/2PP4/2N1PN2/P1Q1BPPP/R1B1R1K1 b - - 0 11


The last move of white is 11.Re1!, and the author said black can no more play exd4 because the queen has to retreat from the column e with a loss of time.

But there is still the bishop in the column e!
Is it a master subtlety? I mean that if the bishop moves, it has no threats and the black queen has time to escape from the column e...

Thank you.
Very good question and I'll try my best to answer properly. As you correctly pointed out, there would be no direct threat on the black queen after 11...exd4 12.exd4 because of the e2 bishop on the e-file (and no good discovery). But if we think further, what does the rook e1 really achieve for the white camp in the current position? Honestly, it's not doing much at all: protecting an already protected bishop and that's about it. Now considering the position after 11...exd4 12.exd4. In that case, the e1-rook is ideally placed on a open file and almost directly facing the black queen. Black would have to lose a tempo at some point by moving his queen and white could prepare an invasion on this e-file. Obviously it's a long-term plan but it's actually what strategy is all about! 
To conclude, I would say that 11...exd4 is not a great move because it justify the previous white move 11.Re1.