Possibly because you are aware, as am I, that pain in the legs and inability to move them correctly are a sign of blood clots. It could have been something else but for the doctors not to heed these symptoms and run an MRI on her is criminal. The biggest danger of blood clots of any area is their breaking loose and going to the lungs to form a pulmonary embolism, almost a certain death sentence.
MRI is not indicted for the symptoms described.