CONTROVERSIES IN MAGNETIC-RESONANCE-IMAGING OF THE HIP

One of the first musculoskeletal areas to be imaged by magnetic resona nce (MR) was the hip. Early on, and even today, the most frequent indi cation for imaging of the hip has been for the evaluation of osteonecr osis and related diseases. Despite the long history of MR imaging of o steonecrosis, there still exist many controversies. This article will look at three of these: (a) What is the best way of imaging early oste onecrosis? This question has proven to be particularly important in th e evaluation of the posttraumatic patient. We provide some preliminary evidence that the use of gadolinium-enhanced MR imaging may be helpfu l. Specifically, gadolinium fails to enhance areas of early osteonecro sis while surrounding uninvolved areas do enhance. (b) How should the patient with ''MR bone marrow edema of the hip'' be evaluated and trea ted? If there is radiographic osteopenia, the assumption is that this represents transient osteoporosis (a self-limited disease) and no trea tment is necessary. However, if no osteopenia is present, the diagnosi s and treatment become more problematic. A decision-making algorithm i s presented to help overcome this dilemma. (c) Is documented osteonecr osis of the hip ever reversible without surgical intervention? Work do ne with renal transplant patients suggests that the answer to this que stion is yes, but work reported from Europe casts some doubt on this c onclusion.