Three cases of malignant tumors of the maxillary sinus were examined by MRI and CT to determine the tumor extension. One case of rhabdomyosarcoma and two of squamous cell carcinoma were examined. The images obtained were examined independently to evaluate the structure and the extension of the tumor.
The results:
1) CT images clearly indicated bone destruction of the maxillary sinus wall better than MRI images.
2) With regard to the observation of the inner structure of the tumor, CT images were not useful. However, the inner structure could be observed by examining T2 weighted images and contrast enhansed images of MRI.
3) About the tumor extension, the surrounding soft tissue (ex. muscle) could not be clearly distinguished by CT images. Furthermore, the muscles and the inflammatory tissue, which could not be recognized in CT images, could be distinguished from tumors by T2 weighted images.
We concluded that MRI images have an advantage to CT images in the diagnosis of malignant tumor of the maxillary sinus, especially for estimating the tumor extension.
