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Histologic correlation in magnetic resonance imaging of femoral head osteonecrosis
H E Jergesen1, P Lang, M Moseley
1Department of Orthopaedic Surgery, University of California, School of Medicine, San Francisco 94143-0728.
Abstract:
The present study was undertaken to determine whether a correlation exists between localized magnetic resonance image (MRI) signal behavior and specific histopathologic features of femoral head osteonecrosis. Contiguous, 5-mm coronal MRI sections were compared with corresponding histologic sections from six surgically excised femoral heads. After identifying specific areas of interest on the images, signal intensity was evaluated, both subjectively and objectively, and T1 and T2 relaxation times were calculated. Mean values for these data were compared among the following histologic categories: normal bone, unrepaired dead bone and marrow, unrepaired dead bone with marrow replaced by amorphous debris, and zones of repair. For each type of tissue, MRI signal intensity on T1- and intermediately T2-weighted images behaved in a distinctive fashion. Active repair tissue could be differentiated from both necrotic bone and normal bone by a tendency for the signal to increase in intensity on intermediately T2-weighted images. These findings suggest that MRI may provide a noninvasive means of quantitatively analyzing the volume and spacial distribution of repair tissue in osteonecrotic femoral heads. In clinical practice, such analysis may lead to improvements in disease staging and treatment planning.
Insights
Magnetic resonance imaging (MRI) shows distinct signal patterns correlating with femoral head osteonecrosis stages. This technique may noninvasively assess repair tissue in osteonecrosis, aiding treatment planning.
Area of Science:
- Orthopedics
- Radiology
- Pathology
Background:
- Osteonecrosis of the femoral head (ONFH) involves bone death, leading to potential collapse.
- Accurate staging and assessment of repair are crucial for effective treatment planning.
Purpose of the Study:
- To correlate localized magnetic resonance image (MRI) signal behavior with histopathologic features of ONFH.
- To investigate MRI's potential for noninvasively quantifying repair tissue in ONFH.
Main Methods:
- Comparison of contiguous 5-mm coronal MRI sections with corresponding histologic sections from six femoral heads.
- Subjective and objective evaluation of signal intensity and calculation of T1 and T2 relaxation times.
- Comparison of MRI data across histologic categories: normal bone, unrepaired dead bone, and repair zones.
Main Results:
- Distinct MRI signal intensities on T1- and T2-weighted images were observed for different tissue types.
- Active repair tissue showed increased signal intensity on intermediately T2-weighted images, differentiating it from necrotic and normal bone.
- MRI signal behavior correlated significantly with specific histopathologic features of ONFH.
Conclusions:
- MRI can differentiate between normal, necrotic, and repairing bone in the femoral head.
- MRI offers a noninvasive method for quantitative analysis of repair tissue volume and distribution in ONFH.
- These findings suggest MRI can improve disease staging and treatment planning for ONFH.