下颌骨骨肉瘤影像学分析

目的:分析下颌骨骨肉瘤影像学表现,评价不同影像检查方法的优劣。方法:7例下颌骨肿块患者中均经X线和MRI检查,6例行CT并经手术病理证实为下颌骨骨肉瘤。所有病例的影像学特点和诊断价值均被分析比较。结果:X线检查有7例病变显示不清;6例呈棉絮状和不规则高密度,1例呈低密度,内有间隔;3例见骨膜反应呈“日光放射状”和“花边状”。CT平扫显示2例呈高密度,4例呈混合密度伴有骨皮质破坏、中断;5例见“日光放射状”骨膜反应;CT增强显示所有病例均有不均匀强化表现,4例伴有软组织肿块形成。平扫MRI显示5例病变T1WI上呈等、低信号,T2WI上呈高信号;2例在T1WI和T2WI上均呈等、低信号;增强MRI显示2例病灶轻度强化;2例呈边缘强化,其内强化不均。结论:CT和MRI均可清晰显示下颌骨骨肉瘤的形态和内部结构,MRI显示髓内病变范围方面优于CT。

Evaluation of Imaging Modalities and Radiographic Findings of the Osteosarcoma of the Mandible

Objective:To study the radiological features of osteosarcoma of the mandible with particular references to the effectiveness of the different radiographic modalities used.Methods:A total of 7 patients were pathologically proved osteosarcoma in mandible.Panoramic radiography (or AP skull radiography),CT and MRI were performed in six cases.One case was examined only by X-ray and MR.Results:On the radiographs the lesions of six cases showed irregular high density and one showed low density and multilocular appearance.The periosteum of three cases showed the sunburst appearance.Of the six cases performed CT scanning,all showed cortical bone destruction with clear margin.The lesions of four cases extended into the adjacent soft tissue,and sunburst appearance of the periosteum was seen in five cases.On T_1WI the signal was isointense or hypointense in seven cases.On T_2WI the signal was isointense or hypointense in two cases,hyperintense in five cases.All lesions on CT and MRI showed hetrogeneous enhancement.Conclusion:Radiological diagnosis of osteosarcoma of the mandible is difficult because of its variable appearance.CT provides excellent detection of tumor structure and cortical involvement.MRI can display the intramedullary extension of the tumor.So CT and MRI are crucial for the planning of surgery.