MRI IN DIAGNOSIS AND ASSESSMENT OF OSTEON ECROSIS

The causes of osteonecrosis are varied. The pathogenesis of osteonecro sis subsequent to trauma is well known. Furthermore, an association of this disorder with cortisone. haemoglobinopathies, rare metabolic dis eases, and risk factors seems to be evident. However, a sizable propor tion of patients have osteonecrosis in which none of these association s exists, referred to as idiopathic osteonecrosis. Generally, intraoss eous vascularization represents the common pathway for the various cau ses of the disease. The prognosis is influenced by the age of the pati ent, the location of the necrosis and the stage of the disease at the time of diagnosis. In recent times diagnosis has been improved by the use of modern imaging modalities, and MR imaging is now widely accepte d as the imaging method of choice. It not only allows early diagnosis but also yields exact staging information in advanced disease, which i s a requirement for adequate therapy.