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Avascular necrosis of the femoral head: high-field-strength MR imaging with histologic correlation
P Lang1, H E Jergesen, M E Moseley
1Department of Radiology, University of California, San Francisco 94143.
Abstract:
Magnetic resonance (MR) images, contact radiographs, and histologic sections of six femoral head specimens with avascular necrosis were correlated. A low-signal-intensity band or ring represented the repair tissue interface surrounding a high-signal-intensity necrotic marrow segment. Large segmental areas of low signal intensity were observed on T1-weighted images when the lesion consisted of necrotic bone with amorphous marrow debris and adjacent thickened trabecular bone with mesenchymal repair tissue infiltration. On intermediate-weighted images, however, mesenchymal repair tissue, which was located inferior to the necrotic zone, increased markedly in signal intensity, permitting distinction from low-intensity necrotic bone with amorphous marrow debris. When trabecular thickening with collapse predominated, segmental areas of low signal intensity with both sequences were found. MR signal intensities used in combination with anatomic configuration and location may provide information of potential therapeutic importance regarding tissue composition and stage of disease.
Insights
Magnetic resonance imaging (MRI) reveals distinct signal intensities in avascular necrosis of the femoral head, differentiating necrotic bone from repair tissue. These findings aid in assessing disease stage and guiding potential therapeutic strategies.
Area of Science:
- Orthopedic Surgery
- Radiology
- Pathology
Background:
- Avascular necrosis (AVN) of the femoral head is a debilitating condition.
- Accurate staging and characterization of AVN are crucial for effective treatment planning.
Purpose of the Study:
- To correlate Magnetic Resonance (MR) imaging findings with contact radiographs and histologic sections in femoral head avascular necrosis.
- To evaluate the utility of MR signal intensities in differentiating necrotic bone from repair tissue in AVN.
Main Methods:
- Correlation of MR images (T1-weighted and intermediate-weighted), contact radiographs, and histologic sections from six femoral head specimens with AVN.
- Analysis of signal intensity patterns associated with necrotic marrow, repair tissue, and thickened trabecular bone.
Main Results:
- A low-signal-intensity band/ring on MR images indicated the repair tissue interface surrounding high-signal-intensity necrotic marrow.
- T1-weighted images showed large low-signal areas with necrotic bone and mesenchymal repair tissue infiltration.
- Intermediate-weighted images distinguished repair tissue from necrotic bone due to increased signal intensity.
- Trabecular thickening and collapse resulted in low signal intensity on both sequences.
Conclusions:
- MR signal intensities, combined with anatomical details, can provide valuable information on tissue composition and disease stage in femoral head AVN.
- This imaging approach may assist in determining therapeutic importance and guiding treatment decisions for AVN.