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目的 探讨动物早期股骨头缺血性坏死 (ANFH)的影像表现及病理基础 ,为临床诊断提供依据。材料与方法 选择 18只自然放养的健康山羊 (雌雄、年龄不限 )制成股骨头坏死模型。正常对照组为同体未手术侧股骨头。术后 1、2、3、4、5、7、12周分别作MRI、X线、CT检查。在影像检查完毕后 ,立即取出双侧股骨头 ,用肉眼观察、对比外表后以光学显微镜进行病理观察。结果 X线、CT检查 7周以前均无阳性表现 ;12周X线检查 3只仅 1只见密度稍降低 ,而CT检查 3只密度均较明显降低。MRI于 1周检查 9只中 6只出现信号异常。 3～ 12周所检查的山羊MRI信号均出现异常 ,12周以前所有检查均未见股骨头外形改变。病理变化是 1～ 2周单纯骨髓局灶性溶解 ,骨小梁间出现不定形细胞碎片及肉芽组织形成 ,脂肪组织未或刚开始液化 ;3～ 7周骨髓继续坏死并纤维组织增生 ;12周骨髓坏死停止并开始出现新骨。早期ANFH的 3种影像学检查以MRI最敏感。结论 X线和CT在 7周前不能反映股骨头缺血坏死的病理变化 ,12周后因骨细胞大量坏死、脱钙才发现有轻微的骨密度降低和骨小梁结构紊乱等 ,故其敏感性差。早期ANFH的影像检查X线和CT的意义不大。MRI检查在 1周开始即可检出异常信号改变 ,其敏感性较高。早期ANFH的影像检查首选MRI。
Objective To investigate the imaging manifestations and pathological basis of early avascular necrosis of femoral head (ANFH) in animals and provide the basis for clinical diagnosis. Materials and Methods 18 healthy goats (male and female, no age) were selected to make the model of femoral head necrosis. The normal control group was the same as the unoperated femoral head. 1,2,3,4,5,7,12 weeks after surgery for MRI, X-ray, CT examination. After the imaging examination, immediately remove the bilateral femoral head, with the naked eye, compared with the appearance of the pathological observation with an optical microscope. Results X-ray and CT examination showed no positive expression at the 7th week. The density of X-ray and CT examination was slightly lower than that of the X-ray and CT examination at 3 of 12 weeks. Six of nine out of nine examined by MRI at 1 week showed abnormal signals. The MRI signals of goats examined in 3 ~ 12 weeks were abnormal. No changes of femoral head shape were found in all the examinations before 12 weeks. Pathological changes were 1 ~ 2 weeks of simple bone marrow focal lysis, trabecular bone between the amorphous cell debris and granulation tissue formation, adipose tissue has not begun or liquefied; 3 to 7 weeks of bone marrow necrosis and fibrosis; 12 weeks Necrosis of the marrow stops and new bone starts to appear. Three imaging studies of early ANFH were most sensitive to MRI. Conclusions X-ray and CT can not reflect the pathological changes of avascular necrosis of the femoral head after 7 weeks. Because of the massive necrosis of osteocytes after 12 weeks, the bone density decreased and the structure of trabecular bone were found to be decalcified, so X-ray and CT were sensitive Poor sex. Early ANFH imaging X-ray and CT is of little significance. MRI examination in the first week to detect abnormal changes in the signal, the higher the sensitivity. Early ANFH imaging examination preferred MRI.