Functional imaging in the early diagnosis of dysbaric osteonecrosis.

Eight divers who developed permanent scintigraphic bone changes following dives to various depths took part in a study to determine the nature of these lesions. Only one of these divers had radiologically evident bone changes in his scintigraphic lesion. Dynamic scintigrams of the bones containing the lesions were obtained from all eight divers and functional images generated of both amplitude (osteoblastic activity) and accretion (microvasculature) rate constants. All had increased amplitude in the area of the scintigraphic lesion indicating continuing osteoblastic activity. Three divers showed a decreased accretion rate in the lesions, indicating impairment or absence of local microcirculation; one of these was the diver who showed radiological changes prior to the study and the other two subsequently developed radiologically evident osteonecrosis. It is concluded that functional images, generated from dynamic bone scintigrams, can successfully predict dysbaric osteonecrosis.