NASOPHARYNGEAL CARCINOMA - MRI AND CT ASSESSMENT

Precise assessment of the extent of nasopharyngeal carcinoma (NPC) rep resents the basic step towards optimal treatment. We compared the capa city of CT and MRI in assessing the extent of NPC in 67 patients. MRI was superior to CT in demonstrating lesions in the retropharyngeal nod e, skull base, intracranial area, carotid space, longus colli muscle a nd levator palatini muscle. Of 25 cases in which retropharyngeal adeno pathy was recognised only on MRI, seven had been reported as showing o ropharyngeal involvement and 18 as primary extension to the carotid sp ace on CT. MRI showed skull-base involvement in 40 patients compared w ith 27 on CT and intracranial involvement in 38 patients versus 24 on CT. There was not a single case in which skull base invasion was seen on CT but not on MRI. MRI enabled improved recognition of tumour infil tration of longus colli muscles (34 cases compared with 15 on CT). It allowed us to clarify 12 questionable sinonasal opacities on CT. Overa ll, T-staging was changed in 18 of 67 patients (26.9%), including upst aging in 15 cases and downstaging in 3 cases, after comparing CT with MRI. The nodel status was changed from negative on CT to positive on M RI in 4 of 67 patients (6%). We believe that MRI allows more accurate evaluation of the extent of NPC than CT and should be the primary mode of investigation.