How an MRI works - What a Medical Student Should Know

Often times in medical school, we are taught the algorithms for patient care. However, due to the volume of information, less care is taken to make sure students understand what exactly they are ordering when they work up a patient. Diagnostic imaging can be a particularly confusing area.

Historically, X-rays were the first mode of imaging and have been the primary mode for the past 100 years of medicine. A more recent development has been computed tomography, or CT. The CT basically takes a series of x-rays and integrates the data to create a more detailed image. X-rays and CTs effectively work on the same principle, which will be discussed in more depth in another post.

Magnetic Resonance Imaging (MRI) is a relatively new form of imaging. Although MRIs are becoming increasingly popular, their cost makes them prohibitive for broad use, so far. Some common questions med students might have when introduced to MRIs are: what is an MRI? How does it work? What is the difference between a T1 image? T2? FLAIR? As a med student, I claim no expertise in this area, but here is what I have learned.

...eh, on second thought, why reinvent the wheel? I can't do as good a job as some of the following sites:

• Howstuffworks
  
  
• Physics 24/7 - The first link has a good short powerpoint which explains the basic idea.
  

• And, of course, Wikipedia
  

Heh, if I end up going into Radiology, maybe I'll come back and expand this post someday when I understand it all better.