Symposium

Bluemke, D.A.
Johns Hopkins University School of Medicine; Department of Radiology;
Baltimore, MD

MR imaging is the optimal method for diagnosing osteonecrosis. It provides high resolution cross-sectional evaluation of the femoral head. Osteonecrosis is intrinsically a bone marrow process, and the high contrast of the normal bone marrow fat provides excellent contrast to the dark band of osteonecrosis on T1 weighted images. Unfortunately, MR imaging is also expensive compared to radiography, and is therefore not regarded as a screening examination. In this discussion, the utility of a fast "screening" MR examination in detecting osteonecrosis will be presented. This screening examination has a high sensitivity (98%) compared to "full" MR examinations of the hip, and can be performed in approximately 10 minutes. This screening examination should thus have substantially lower cost than standard MRI. "Newer" MR pulse sequences, such as fast spin echo imaging, perfusion and spectroscopy will also be discussed in the context of their impact on osteonecrosis diagnosis and characterization.