[Comparison of computerized tomography and magnetic resonance in staging of T and N parameters in head and neck neoplasms].

January 1990, through January 1994, eighty untreated patients with head and neck cancer were consecutively submitted to CT and MRI of the head and neck before surgery. CT and MR findings were then compared to operative histologic findings. Forty-eight of 52 T4 cases at CT were confirmed at surgery (89%), 7 of 13 T3 cases at CT were also confirmed (54%), as well as 8 of 15 T2 cases (53%). CT understaged 13 cases (6 T3 and 7 T2), which surgery staged as T4, CT overstaged 4 cases as T4, which were 2 pT2 and 2 pT3 at histology. All the 54 cases MRI staged as T4 were confirmed at surgery (100%), 3 of 12 MRI staged as T3 were pT4 at surgery (25%) and, finally, 4 of 14 cases MRI staged as T2 were pT4 at histology (28%). Only one case staged as pT4 at surgery and CT had been staged as T3 by MRI because the latter method had failed to depict hyoid involvement. On the other hand, in 6 cases MRI correctly modified CT staging. Overall CT accuracy was 79% and MR accuracy 91%. CT sensitivity was 70% versus 75% with MRI, specificity was 80% versus 78%, respectively, and overall accuracy 75% versus 76%. Only in two patients MRI correctly modified CT staging (N1 at surgery). Our results confirm various advantages of MRI over CT in the assessment of tumor mass ("T" parameter), mainly in T2 and T3 cases, because MRI yields higher soft tissue contrast resolution and has multiplanar capabilities. CT was superior to MRI only in the assessment of bone involvement. This study also confirmed similar CT and MR capabilities in detecting lymph node tumor spread. Finally, MRI did not allow earlier detection of micrometastases than CT.