鼻咽癌放疗后局部复发特殊类型的MR诊断

目的　探讨鼻咽癌放疗后局部复发的类型及其 MR表现。方法　选择鼻咽癌放疗后鼻咽腔粘膜正常 ,但鼻咽周围肿块复发者 2 4例 ,按常规及 Gd- DTPA增强后行 MR检查。结果　 1茎突前间隙复发 8例 ,7例伴有颅底和颅内侵犯 ;2茎突后间隙复发 2例 ;3颅底骨质破坏 7例 ;4鼻腔及筛窦复发 3例 ;5鼻咽腔粘膜下囊性复发 2例 ;6其他类型复发 2例。其中 15例还经病理证实 ,9例经再程放疗和追踪观察确诊。在 MR表现上除囊性复发 2例外 ,其余病例病灶在 T1加权像均呈稍低或等信号 ,T2加权像呈稍高信号 ,增强后有中等度以上强化。结论　鼻咽癌放疗后复发存在多种特殊类型 ,MR是检查鼻咽癌放疗后复发的较好方法

Local Recurrence of Nasopharyngeal Carcinoma with Normal Mucous Membrane after Radiation therapy: MR Imaging Findings

Objective The purpose of this work was to investigate and analyzethe MR imaging features of postradiation local recurrence of nasopharyngeal carcinoma(NPC) with normal mucous membrane. Methods 24 such cases were studied. The diagnosis of NPC recurrence was pathologically confirmed in 15 patients, and was corroborated by repeated radiation therapy and serial follow-ups in 9 patients. MR imaging routine procedures and Gd-DTPA enhancement were performed for all patients. Results The MR imaging findings were as follows: ① The recurrent tumor mass was located in the prestyloid space in 8 patients, with skull base erosion and intracranial infiltration in 7 patients; ② Retrostyloid space recurrence in 2 patients; ③ Direct bony erosion of the skull base in 7 patients; ④ Recurrence in nasal cavity and ethmoid sinuses in 3 patients; ⑤ Submucous cystic recurrence in 2 patients; ⑥ Mixed patterns of recurrence in 2 patients. Except 2 cases of cystic tumor recurrence, all cases exhibited slight hypo- or iso-intensity on T1-weighted images, slight hyper-intensity on T2-wighted images, and moderate to marked enhancement after Gd-DTPA administration. Conclusion There are several special patterns of local NPC tumor recurrence after radiation therapy in the presence of normal nasopharyngeal mucosa. MR imaging is the method of choice to depict the location and extent of NPC tumor recurrence.