IMAGING OF PAROTID TUMORS - US VERSUS MRI

27 patients, clinically suspected of having parotid tumours, were exam ined prospectively by sonography (high frequency linear array) and MRI (1.5T, T1- and T2-weighted SE sequences before, and T1-weighted SE se quences after contrast). In 23 patients, 25 intraglandular tumours wer e demonstrated (two were multicentric); they consisted of 6 malignant parotid tumours, 11 pleomorphic adenomas, 7 cystadenolymphomas and one oncocytic adenoma. 4 patients had extraglandular tumours. All tumours were demonstrated by either method, but two extraglandular tumours we re incorrectly diagnosed by sonography as being intraglandular and 8 t umours (28 %) were not completely delineated by sonography. MRI locali sed the tumours correctly in all cases and demonstrated all lesions ac curately, independent of their position or size. In summary, sonograph y appears suitable as the primary imaging method in the investigation of parotid tumours but in case of large, parapharyngeal or malignant t umours, MRI is clearly superior to sonography.