MRI和C T成像差异对鼻咽癌侵犯范围界定及放疗靶区勾画的影响

摘要

Objective:To investigate the impact of difference between MRI and CT finding on involved structures of nasopharynx and gross target volume (GTV)of the three-dimensional conformal radiotherapy (3DCRT)in naso-pharyngeal carcinoma (NPC).Methods:All 85 cases of NPC confirmed by pathology were performed CT and MRI scanning before treatment,the similarities and differences of involving structure of nasopharynx and lymph node metas-tasis showed on MRI and CT were compared,GTV based MRI and CT were delineated respectively and the volumes were compared.Results:Prevertebral muscle invasion,skull base invasion and retropharyngeal lymph node metastasis shown on MRI and CT were 44,59,56 cases and 65,28,23 cases respectively,the difference was statistically signifi-cant (P<0.01).GTV-MRI increased by 35.67%on an average,compared with GTV-CT,the difference was sta-tistically significant (P<0.01).Conclusion:MRI is superior to CT in demonstrating the involved structures of naso-pharynx for NPC,and combined application of both can improve the contouring of target volume and minimize the missing of tumor target.%目的：探讨MRI与CT成像差异对鼻咽癌（NPC）侵犯范围的界定及三维适形放疗靶区勾画的影响。方法：我院经病理证实的初诊NPC患者85例行CT与MRI检查，对比其向周围结构侵犯和淋巴结转移的异同。分别勾画鼻咽原发肿瘤范围并比较其靶体积（GTV）的差异。结果：MRI和CT显示椎前肌侵犯、颅底骨质破坏、咽后淋巴结转移分别为44、59、56例和65、28、23例，差异具有统计学意义（P＜0．01）。GTV-MRI较GTV-CT平均增大35．67％，差异具有统计学意义（P＜0．01）。结论：MRI对NPC侵犯范围的显示较CT有优势，联合应用将有助于提高NPC放疗靶区勾画的精确性，减少肿瘤靶区的遗漏。