骨样骨瘤的影像学评价

Imaging assessment of osteoid osteoma

目的 评价数字化X线（DR）、单层螺旋CT（SCT）、多层螺旋CT（MSCT）和MRI在诊断骨样骨瘤中的价值。方法收集经手术病理证实的骨样骨瘤19例，均行DR及CT检查，8例同时行MRI检查。DR检查后行图像后处理，10例行SCT横断位扫描，9例行MSCT各向同性扫描及多平面重建（MPR）。分析DR、SCT、MSCT和MRI对瘤巢和瘤巢周围改变的显示能力。结果19例DR检查图像处理前显示瘤巢6例，图像处理后显示瘤巢12例，19例CT检查均清楚显示瘤巢。8例MR检查直接判断出瘤巢4例，2例结合DR或CT做出正确诊断，另2例误诊。10例SCT检查显示瘤巢中心钙化6例，9例MSCT检查显示瘤巢中心钙化8例。8例MRI检查均可见瘤巢周围的软组织及骨髓水肿。结论瘤巢是确诊骨样骨瘤的关键；DR是诊断骨样骨瘤的基本方法，DR图像后处理有利于瘤巢的显示；CT是显示瘤巢的最佳方法；MSCT对瘤巢及瘤巢周围改变的显示能力优于SCT；MRI能敏感地显示瘤巢周围骨髓及软组织的炎性水肿，但单凭MRI可能造成误诊，结合DR或CT可作出准确诊断。

Objective To assess the diagnostic value of DR, SCT,MSCT and MRI in diagnosis of osteoid osteoma. Methods Nineteen cases of osteoid osteoma proved by surgical pathology were collected. Among the 19 cases, all patients had DR and CT scanning, 8 with MR imaging. All the DR image processing were performed to display the nidus. Ten patients were examined by SCT axial scanning and 9 cases were performed by MSCT using isotropic parameters,then multi-direction MPR were performed . The ability of DR, SCT, MSCT and MRI in demonstrating the nidus and the surrounding reaction were analyzed. Results Among 19 cases,only 6 cases showed nidus on DR before image processing and 12 showed nidus after image processing. All cases with CT scanning showed nidus. Among 8 cases with MRI ,only 6 cases could be diagnosed correctly. The nidus could be affirmed in only 4 cases, and the nidus was affirmed by comparing with DR or CT in 2 cases ,the other 2 cases were misdiagnosis. Among 10 cases with SCT,only 6 cases showed calcification of nidus. Whereas among 9 cases with MSCT, 8 cases showed calcification of nidus. There were also soft tissue and bone marrow edema around the nidus on MR imaging in all 8 cases. Conclusion Nidus is the key in diagnosing the osteoid osteoma correctly. DR is a basic checking method for osteoid osteoma. DR image processing can improve the display rates of nidus. CT scan is the best method to demonstrate the nidus. MSCT is better than SCT in demonstrating the nidus and the surrounding reaction. MRI can demonstrate the soft tissue and bone marrow edema around the nidus sensitively, but probably lead to an incorrect diagnosis. Combining with DR or CT,MRI can make an accurate diagnosis.