LARYNGEAL IMAGING BY COMPUTERIZED-TOMOGRAPHY AND MAGNETIC-RESONANCE FOLLOWING RADIATION-THERAPY - A NEED FOR CAUTION

For patients with laryngeal tumours, the use of computerized tomograph y (CT) or magnetic resonance imaging (MR) may facilitate accurate stag ing by the demonstration of cartilage invasion or tumour extension to areas such as the pre-epiglottic space. The role of imaging in the fol low-up of patients after radiotherapy, however, has not been examined. A prospective study of 18 patients undergoing laryngectomy was perfor med. The results of pre-operative CT and MR imaging were correlated wi th the pathological findings from whole organ axial sections of the la ryngeal specimens. In five patients (28 per cent) both CT and MR image s were significantly impaired by movement artefact. In the eight patie nts without previous radiotherapy, seven had adequate quality imaging and both CT and MR accurately demonstrated the site, size and extent o f laryngeal tumour. In eight of die ten patients following radiation t herapy die presence of tumour was correctly identified, however there was a poor correlation between the imaging and pathological findings. Two patients had radionecrosis alone. Neither CT nor MR imaging could differentiate between radionecrosis and recurrent tumour.