MRI of nasopharyngeal cancer with skull base invasion after radiotherapy. Application for therapeutic effect evaluation

Serial MRI of nasopharyngeal cancer in 10 patients who had T4 disease with skull base invasion and treated with radiotherapy at Hyogo Medical Center for Adults from July 1988 to December 1992 were analyzed in comparison of their prognosis. Purpose of this study was to know whether it is possible to apply MRI just after radiotherapy for therapeutic effect evaluation. All cases showed the residual tumor at termination of treatment and 6 of them were judged as PR by size evaluation, Five of them showed low signal intensity (LSI), 4 high signal intensity (HSI) and 1 mixed signal intensity on T2 weighted image (T2WI), whereas all of them showed LSI on T1 weighted image. Three of 5 cases who left LSI mass on T2WI presented much reduction on 6 months in advance. LSI group on T2WI showed more favorable prognosis (4/5 alive) than HSI group (1/4 alive). (author)