MR imaging of the hip in avascular necrosis: Radiologic-pathologic correlation

MR imaging is the most sensitive modality for diagnosing avascular necrosis (AVN), but there is no established explanation for the change of signal intensity of the osteonecrotic segment. Ten surgically removed femoral heads with AVN underwent MR imaging at 2.0 T. A combination of high gradient strength (0.1 m T/cm) and small radio frequency coil (8 cm in diameter) was used to obtain images with effective thickness of 2.0 mm and pixel dimensions as small as 200 μm. MR images were correlated with high-resolution CT and histologic findings. This paper illustrates how MR images the histologic findings of AVN