Re: MRI vs. Ultrasound of Foot
Hopefully you are going to a doctor that can explain this to you.
Ultrasound is a lot cheaper, but less exact or precise. It will not be able as clearly to determine any changes within the bone (stress fractures) and most likely won't give you much information about your arch either.
When your doctor orders your MRI, he needs to have a presumed diagnosis. MRIs are complicated and the numbers that are used to generate the images are manipulated to assist in diagnosis and the structure in question needs to be known to the radiologist. MRIs can and will generate alot of data and information and sometimes tell you more than you need to know.
Stress fractures usually don't require an MRI. Xrays will show one most of the time about 2 weeks after the onset of symptoms.
Neuromas - particularly around the toes - are usually too small and not well visualized by MRI.
Arch problems can be caused by a number of factors (plantar fascia, Posterior tibial tendon dysfunction, equinus, etc.) and these need to be determined prior to any test so that the correct one is chosen.
Hope this helps.