@donasmrs-- Both an MRI without contrast and an MRI with contrast may be ordered for most conditions.
Like the article said, MRI with contrast can give more detailed images or show things that a standard MRI may not. So a doctor may first request a standard MRI and if he or she doesn't get good results from it, an MRI with contrast may be requested. MRI with contrast has better resolution and can show more details.
If a standard MRI will do the job though, a doctor is not going to order an MRI with contrast since there is a dye that has to be injected. Some people are allergic to these dyes and can have bad side effects to them. So an MRI with contrast is reserved for more sensitive and serious cases where a standard MRI is not enough.