Check the pinout of both air flow meters for a start( on a wiring diagram). If both are the same you could probably use the 18rgeu one, the only difference being a large diameter and possible a different voltage response. But you could proably tune this and it would work OK. If cant get an 18rg one why not use a 2se leaded camry one.
I have interchanged air flow meters between 2se, 3tgteu and a fiat(bosch) with no difference in performance between all 3. Note all have the same pin out also. But I did check the voltage response before hand ie min and max voltage out puts and all were identical.
I don't know why people who choose to go the nippon denso ljet system just don't use the camry system it would have to be almost identical to the 18rg one. If you ever do this though check the resistance of the injectors and need for ballst resistor before you blow up your 2se ecu.