ELI5: How MRI works?

Imagine you have a bunch of tiny magnets inside you, like little compasses. These are your hydrogen atoms, and they're everywhere in your body because you're mostly water!

Here's how an MRI (Magnetic Resonance Imaging) works like magic:

1. Strong Magnet: The MRI machine has a HUGE magnet, much stronger than a fridge magnet. When you lie inside, all those tiny compasses (hydrogen atoms) line up, like soldiers following orders.

1. Radio Waves: The machine then sends out radio waves, like a tiny radio station broadcasting a signal. These radio waves "nudge" the lined-up compasses, making them wobble. Think of it like gently pushing a line of standing dominoes.

1. Listening to the Echo: When the radio waves stop, the compasses wobble back into their original position. As they wobble, they send out their own tiny radio signals, like echoes.

1. Building a Picture: The MRI machine has special ears (detectors) that listen to these echoes. Different tissues in your body (like your brain, muscles, or bones) send out slightly different echoes.

1. Computer Magic: A computer takes all those echoes and turns them into a detailed picture. It's like painting a picture with sound! The computer knows what kind of tissue sent each echo, so it can show a clear image of what's inside you.