Imaging modalities in avascular necrosis of the hip

Diagnosis of avascular necrosis (AVN) of the hip has been improved by the t echnical progress of imaging modalities during the last decade. For a long period, only plain radiographs had been available. Scintigraphy and compute d tomography contributed to differential diagnosis and early detection of b one necrosis. In the meantime, MR imaging has gained special value in the e valuation of AVN. It is now the method of choice for early detection as wel l as for assessment in later stage disorders. Using the ARCO system, all im aging modalities and their diagnostic viability are described. Findings reg arding the different stages of AVN are correlated to tissue-specific change s.