RANKING OF MR TOMOGRAPHY AND CT IN TUMOR STAGING OF CARCINOMA OF THE LARYNX HYPOPHARYNX

43 patients with malignant tumours of the larynx or hypopharynx were e xamined by MRT and CT to compare their accuracy for T-staging. There w as histological confirmation in all cases. Histological studies showed an accuracy in T-staging of 90% for MRT and 82% for CT. Differentiati on between stages T2/T3 and T3/T4 is possible in most cases by either method. A source of error is the difficulty of differentiating oedema or inflammatory changes from tumour. This led to occasional overinterp retation of the T4 stage. Demonstration of cartilage involvement was e asier with MRT (88%) than with CT (84%). The use of Gd-DTPA with T1 we ighted and proton weighted sequences allows earlier diagnosis of carti lage invasion. Early cartilage involvement may be missed by CT when it is seen on MRT. In addition, the ability to produce coronal and sagit tal images by MRT makes this superior to CT in judging tumour extensio n.