MRI Question

[Ken Fitzgerald]

Well, I just read the entire thread and really enjoyed it. It’s an interesting subject so kudo’s to you. I always found the noises made by the MRI machine while having one to be very entertaining.

Michael, the sounds you hear are normally caused by the gradient coils changing the main magnetic field in a precise way.

Have you ever seen a child build something with a set of blocks? Imagine your body built out of a child's blocks. Now we'll call those individual blocks voxels. An MRI image is made by the machine causing each voxel to produce its own distinct, individual RF signal. The machine knows in 3-D from where a given RF signal with a specific frequency was produced. The human body is made up primarily water, H2O. The MRI image is made by studying the hydrogen molecules in the body.

Different pulse sequences will produce dramatically different gradient pulses/fields and thus dramatically different sounds.