MRI transmitted signal 2

[idi88]

can anybody explain to me what type of RF signal we transmit to start an MRI signal? Is it a pure carrier signal; is it amplitude modulated (AM) signal; or is it frequency modulated signal (FM) signal.
Now if it is a pure carrier signal, what will happen if we transmit an AM signal?
If it is an AM signal, how can we change the strength (I assume the power) of the signal; do we change the power of the carrier signal or the power of the modulating signal?

If it is NOT an AM signal, what will happen if we replace the pure carrier signal with an AM signal?

I hope I can get a clear answer for this. Thanks!