ABSTRACT
Objective To evaluate the value of MR and CT examinations in the diagnosis of nasopharyngeal carcinoma (NPC) and compare 2008 staging system with 1992 staging system and 2002 UICC staging system for NPC. Methods MR and CT images of seventy-six cases with NPC were studied. According to 2008 staging system and taking MR as a standard, differences between these two examinations were evaluated under the new NPC staging system, and three staging system were compared by MR findings. Results MR was inconsistent with CT in eveluating invasion of medial pterygoid muscle(22,24 cases), lateral pterygoid muscle( 15, 11 cases), skull base(35, 32 cases) and intracranial fossa( 11,6 cases), but no statistical diffence existed ( P ＞ 0. 05 ). There were statistical difference ( P ＜ 0. 05 )between MR and CT in determining invasion of parapharyngeal space( 50, 61 cases), retropharyngeal lymph node metastasis(48, 23 cases), stage T1 (18, 11 cases), T2 (15, 22 cases), N0 (18, 24 cases) and N1(33, 27 cases) with differences of 11 cases, 25 cases, 7 cases, 7 cases, 6 cases and 6cases respectively.For invasion of parapharyngeal space, CT showed 11 cases more than MR while 5 cases were comfirmed as compression by local tumor and 6 cases were proved as retropharyngeal lymph node metastasis according to MR. For retropharyngeal lymph node metastasis, MR presented 25 cases more than CT. These two reasons above mainly caused the differences of T-staging and N-staging. For 2008 staging system, when compared with 1992 staging system, there were 9 cases upstaging and 1 case downstaging in T classification, 16 cases upstaging in N classification, and 15 cases upstaging and 1 case downstaging in clinical classification; and when compared with 2002 UICC staging system, there were 7 cases, 10 cases and 12 cases upstaging in T,N, and clinical staging respectively. Conclusions Compared with MR examination which was regarded as standard by 2008 staging system of NPC, there were some differences in demonstrating invasion of parapharyngeal space and retropharyngeal lymph node metastasis by CT. Compared to 1992 staging system and 2002 UICC staging system, 2008 staging system mainly made T and N classification of tumor upstage,resulting in upstaging in clinical classification.