Question

1.What form does the signal actually measured in MRI takr?

2.What do we do with the acquired signals to make an image?

Answer 1

1. The signal measured in MRI are in the form of radio fields, under the influence of strong magnetic fields as well as electric field gradients. There are no ionising radiations. There is use of nuclear magnetic resonance.

2. The radio frequencies emitted by the atoms, as these would be placed in external magnetic fields would be used for generation of stable signals, that would be detected by the antennas placed close to the anatomy that is under examination. Radio wave pulses would be exciting the nuclear spin energy transition. Also, the magnetic field gradients would be identified by these pulses, which are present in the local space. As theoulse sequence parameters would be varied, there would be generation of different contrasts, which is based on thr properties of relaxation of the hydrogen present there.