What is this, i hear it on tv, but never thought i might needed to know what it is?

MRI is Magnetic Resonance Imaging. Powerful magnets are used to detect magnetic dipoles in the atoms that make up your body. Water responds differently from bones, which are different from membranes and so on. This allows MRI imaging to see into your body.

CAT scan is a computer axial tomographic scan. This uses X-rays in several different directions to see inside a "slice" of your body.

Both are low risk diagnostic procedures that will allow the doctors to see what has been injured internally without requiring surgery. Depending on the results, they may need to go ahead and get him into surgery anyway, but they may be able to avoid surgery depending on what the damage is.

If they do have to operate, the MRI and/or CAT scan will give the doctors a good idea what to expect.

MRI- Also called NMR. magnetic resonance imaging: a noninvasive diagnostic procedure employing an MR scanner to obtain detailed sectional images of the internal structure of the body.

CAT scan-Short for computerized axial tomography scan. An image of a body structure produced by computerized axial tomography.

In short, they'er taking some serious X-rays to make sure he's all right. MRI and CAT take pictures of ALL the body, not just the bones, and they do it in all 3 dimensions, so it's not just a flat picture, and nothing can hide behind an organ or something.