MRI对鼻咽癌T、N分期的影响

Influence of MRI on the T, N staging sy stem of nasophary ngeal carcinoma

目的 比较 5 6例鼻咽癌患者的CT、MRI资料 ,探讨MRI对国际抗癌联盟 (UICC ,1997年 )分期和我国 1992年福州 广州分期的影响。方法 选取同时进行CT与MRI扫描并经病理证实的鼻咽癌 5 6例。CT扫描用elscientCTtwinflash双螺旋扫描机 ,常规横断平扫 ,3例加冠状扫描 ,16例直接增强扫描。MRI使用PhilipT5 II型 0 .5Tesla超导磁共振成像系统 ,标准头部正交线圈 ,常规SE序列 ,扫描方向为横断面、矢状面和冠状面 ,扫描范围上达鞍上池 ,下至第 2颈椎下缘水平。大部分病例(5 0 / 5 6 )行增强扫描。结果 CT不能显示咽颅底筋膜 ;MRI显示清楚 ,可以确定真正的腔内病变。MRI对显示软组织 (包括颈长肌、腭帆提肌、腭帆张肌 )和颅底骨质肿瘤侵犯较敏感 ,可以发现肿瘤软组织侵犯和早期骨髓侵袭。MRI显示鼻咽癌侵犯颈动脉鞘区和咽后淋巴结转移较CT明确 ,同时可以发现三叉神经肿瘤侵袭 ,直接影响肿瘤临床分期。结论 根据UICC分期原则 ,2 8.6 % (16 / 5 6 )的病例发生分期改变 ;根据我国 1992年分期原则 ,33.9% (19/ 5 6 )的病例发生分期改变。MRI对我国 1992年分期最明显的影响在于区分颈动脉鞘区是肿瘤侵犯还是咽后淋巴结转移 。

Objective To investigate the influence of MRI on the T, N stagin g sy stem, 5 th edition, UICC and the 92 staging sy stem, China by com paring CT and MRI of the nasophary ngeal carcinoma (NPC). Methods From 1993 to Dec. 2000, fifty six NPC patients proved by pathology underwent CT and MRI examination with Philip T5 II ultra magnetic sy stem (0.5T) and Elscient CT twin flash. Routine axial scans by CT and SE sequence with axial, sagittal and coronal scans by MRI from oral phary nx (lower border of second cervical vertebra) to supracellar cist ern were done with enhancement (50/56). Results The tumor bey ond the nasophary ng eal cavity was accurately defined because the phary ngobasilar fascia could be se en by MRI which appeared to be more sensitive than CT in revealing the invaded s oft tissues surrounding the nasophary ngeal cavity , such as longus colli (14 by C T and 26 by MRI), tensor veli palatini and levator veli palatini (17 by CT and 42 by MRI), the sKull base erosion (15 by CT and 23 by MRI) and enlargement of retrophary ngeal ly mph nodes (13 by CT and 24 by MRI). As a result, 28.6%(16/56) of NPC staging sy stem, UICC and 33.9%(19/56) of the 92 staging sy stem of China should undergo changes. Conclusion MRI is able to reveal the invasion extent into the structures around the tumor m ass more accurately than CT, with the phary ngobasi lar fascia readily seen and the infiltration and/or destruction of the sKull bas e more easily visualized by MRI than by CT. The impact of MRI upon the 92 stagi ng sy stem of China lies in the differentiation of direct infiltration by the tu mor from the enlargement of the retrophary ngeal ly mph node and the early de tection of sKull base erosion. The Influence of MRI on the staging sy stem of NPC is more pronounced than that of CT. [