Early Diagnosis of Avascular Necrosis by Magnetic Resonance Imaging

The basic principles of magnetic resonance imaging (MRI) are quite complicated and are beyond the scope of this presentation. This technique depends upon the fact that, in an external magnetic field, certain atomic nuclei can be made to emit a radio frequency signal which is used to generate the image. This signal is sensitive to subtle physiologic and biochemical changes. It can therefore distinguish quite early between healthy and diseased tissue [1–9]. Since the early diagnosis of avascular necrosis (AVN) is essential if we hope to improve its treatment, we felt that MRI might prove to be a useful adjunct in the management of this condition. The objectives of this study were therefore to evaluate the effectiveness of MRI in the early diagnosis of AVN and to compare it to routine radiography, tomography, computerized tomography, and scintigraphy.