鼻咽癌颅底骨改变的CT诊断

CT diagnosis of skull base involvement in nasopharyngeal carcinoma

目的研究鼻咽癌颅骨改变的CT征象。方法对病理证实的鼻咽癌患者并有颅底骨质改变的182例进行CT平扫及增强扫描。采用常规轴位,层厚5mm,层距5mm。用骨窗显示:窗宽2500HU,窗中心300HU。结果颅底骨改变分为骨质硬化、溶骨性破坏和混合性改变。溶骨性破坏最多,常见于斜坡。增强后,溶骨性破坏的颅底骨强化最明显,混合性改变其次,骨质硬化的颅底骨无明显强化,三者之间具有统计学意义(F=5.73,P<0.01)。结论颅底骨硬化可能是一种反性改变,无需大剂量放疗。CT对鼻咽癌颅底骨改变的诊断具有重要的意义,但临床高度怀疑颅底骨质破坏,而CT检查显示颅底骨质正常时,进行MRI检查是必要的。

Objective To study CT features of bone involvement of the skull base in nasopharyngeal carcinoma （NPC） . Methods Non -contrast enhanced and contrast enhanced CT scan were performed in 182 patients with NPC proved by pathology （male 123 and female 59） on an EXEL 2400 elite CT unit. Axial imaging of nasopharynx were obtained with slice thickness of 5 ram and slice interval of 5 mm. The bone window with a width of 2500HU and a level of 300HU was adopted in the evaluation. Results Bone lesions of the cranial base were classified into three types：sclerotic, lytic and mixed. Osteolytic lesions were most common where the clivus was often involved as well. After the contrast media was given, enhancement in osteolytic lesions was the most significant; and then was the enhancement seen in the mixed type; while most of the sclerotic lesions had no enhancement. There was a significant difference among the three types of bone lesions located in the skull base. Conclusion Sclerosis of the skull base in NPC is probably a reactive change, indicating no necessity of high - dose radiotherapy. CT scan is helpful for diagnosis of skull bone lesiones in NPC. MRI examination is necessary if clinical symptoms imply skull base bone encroachment however CT scan is negative.