Learn English – Are you supposed to use capitalized letters when expanding an all-caps initialism in parentheses to explain what each initial respectively stands for


Which of these two is written correctly:

  1. MRI (Magnetic Resonance Imaging)
  2. MRI (magnetic resonance imaging)

Best Answer

This is a matter of style. If there's a style guide required or recommended by wherever you're writing for, follow it. Otherwise, while bearing in mind the need to be consistent within your document, you should do whatever is clearest. It doesn't matter if you only have simple initialisms as in your example, but some form of highlight of the letters that count can be helpful in more convoluted abbreviations. Capitals are a good way to do this. Bold face is often discouraged in body text, and it's certainly not necessary to do both.