骨样骨瘤的影像学分析

摘要

目的 分析骨样骨瘤的X 线、CT 及MRI 影像表现.方法 搜集2000 年～2005 年经病理证实的骨样骨瘤21 例,男13 例,女8 例,年龄6～59 岁.所有病例均行X 线平片;17 例行CT 平扫;MRI 平扫12 例,增强扫描5例(动态MRI 增强扫描3 例),完成三项检查10 例.病灶位于股骨8 例,胫骨7 例,髋臼、胸椎各2 例,锁骨及距骨各1例.分析X 线、CT 及MRI 对瘤巢及其周围组织改变的显示能力.结果 X 线、CT 及MRI 对瘤巢显示率分别为57.1%、76.5%、75.0%,X 线、CT 上瘤巢为一小圆形或卵圆形透亮区,中心有/无钙化和骨化,边缘有不同程度骨硬化;MRI 上瘤巢为一小圆形异常信号区,T1WI 呈低至中等信号,T2WI 呈低至高信号,边缘为低信号骨硬化,瘤周不同程度骨髓及软组织水肿;Gd-DTPA 增强扫描瘤巢明显强化,动态MRI 增强瘤巢呈高灌注表现,时间-信号强度曲线为快速上升后缓慢持续下降(C 型曲线).结论 CT 为诊断骨样骨瘤最佳方法,MRI 能够增加瘤巢可见度并能敏感显示骨髓及周围软组织水肿,一定程度上反映病理组织特点,对骨样骨瘤有较高的诊断价值,可作为CT 的补充检查手段.%Objective To analyze the findings of osteoid osteoma on radiographs, CT and MRI. Methods 21 patients (13 male, 8 female; age range: 6-59 years) with pathologically confirmed osteoid osteoma from 2000 to 2005 underwent radiograph(21) ,CT(17) ,and MRI(12 unenhanced, 2 enhanced, 3 dynamic contrast-enhanced) examinations. Ten patients were investigated with all three modalities. The tumors were located in the femur (8), tibia (7), acetabulum (2), thoracic spine (2), clavicle (1) and talus (1). The radiographs, CT and MRI were retrospectively analyzed. Results Tumor nidus was depicted on radiographs (57.1%), CT (76.5%), and MRI (75.0%). On X-ray and CT, the tumor nidus was a small round or oval translucency with calcification or ossification center and variable degrees of surrounding sclerosis. MRI showed small round nidus of low to intermediate signal intensity on T1WI and low to high signal intensity on T2WI with hypointense rim and variable degrees of peritumoral bone marrow and soft tissue edema. The nidus enhanced intensely and rapidly with gadolinium and washed out slowly. Conclusion CT is the best imaging modality for depicting the tumor nidus of osteoid osteoma. MRI can increase the conspicuity of the nidus by showing the surrounding bone marrow and soft tissue edema. MRI can also reflect the pathological characteristics of osteoid osteoma and can complement CT diagnosis.