骨样骨瘤的影像学诊断

目的 分析骨样骨瘤的X线、CT和MRI表现。方法 搜集经手术病理证实的骨样骨瘤48例，其中男33例，女15例。所有病例均行X线检查，其中同时行CT检查者32例，行MR检查者10例，3种检查方法都进行者8例。分析骨样骨瘤在X线、CT和MRI上的表现及其对瘤巢和瘤巢周围改变的显示能力。结果 48例病灶均表现为一圆形或卵圆形的透亮区，直径为0．4～1．7cm，平均9．7cm，其周围有不同程度的骨质硬化。10例行MR检查者均可见瘤巢周围的软组织、骨髓水肿或关节腔积液。48例X线平片仅37例显示瘤巢，32例行CT检查者均清楚显示瘤巢，X线和CT对瘤巢显示率分别为77％(37／48)和100％(32／32)。10例MR检查者均可作出正确诊断，其中8例能直接判断出瘤巢，另2例需对照平片或CT才能肯定。结论 瘤巢是确诊骨样骨瘤的关键，X线平片仍然是诊断骨样骨瘤的重要检查方法，CT是显示瘤巢的最佳方法，MRI能敏感地显示瘤巢周围骨髓内及软组织的炎性水肿，但可能造成误诊，结合平片或CT可作出准确诊断。

Imaging diagnosis of osteoid osteoma

Objective To analyze the X -ray, CT, and MR imaging findings in osteoid osteoma. Methods Forty-eight cases of osteoid osteoma proved by surgical pathology were collected, including 33 males and 15 females. Among the 48 cases, all patients had plane films, 32 were imaged with CT scanning, 10 with MR imaging, and 8 with all three techniques. The imaging findings of osteoid osteoma and the ability of X-ray, CT, and MRI in demonstrating the nidus and the surrounding reaction were analyzed. Results The imaging manifestations of osteoid osteoma revealed a circular or oval nidus with different bone sclerosis around the nidus. The diameters ranged from 0.4 cm to 1.7 cm, with the average of 9.7 cm. There were also soft tissue and bone morrow edema around the nidus or distinct effusion of joint on MR imaging in all 10 cases. Among 48 cases, only 37 cases showed nidus on plane film. All 32 cases with CT scanning showed nidus. The display ratios of nidus were 77% for X-ray and 100% for CT, respectively. 10 cases with MR imaging could be diagnosed correctly. But the nidus could be affirmed in only 8 cases, and the nidus was affirmed by comparing with plane film or CT in the other 2 cases. Conclusion Nidus is the key in diagnosing the osteoid osteoma correctly. Plane film is still an important checking method for osteoid osteoma. CT scan is the best method to demonstrate the nidus. MRI can demonstrate the soft tissue and bone morrow edema around the nidus sensitively, but probably lead to an incorrect diagnosis. Combining with X-ray or CT, MRI can make an accurate diagnosis.