ASSESSMENT OF PAROTID MASSES - WHICH MR PULSE SEQUENCES ARE OPTIMAL

The objective of this paper is to determine which MR pulse sequences a re optimal for delineation of lesion and predicting pathologic nature of lesion with signal intensity. A prospective study was performed in 53 parotid masses (39 benign and 14 malignant lesions) in 53 patients. Signal intensity of lesion was visually assessed and lesion/parotid c ontrast-to-noise ratios were measured. On visual assessment. detection sensitivity was 100% for nonenhanced nonfat-suppressed T1-weighted im ages, 91% for nonfat-suppressed fast spin-echo (FSE) T2-weighted image s, 83% for gadolinium-enhanced fat-suppressed T1-weighted images, and 75% for fat-suppressed FSE T2-weighted images. The highest contrast-to -noise ratios were obtained with nonenhanced T1-weighted images. Hypoi ntensity of lesion relative to the parotid gland on nonfat-suppressed FSE T2-weighted images was seen in 11 of 14 malignancies, 12 of 15 War thin tumors, and two of 18 pleomorphic adenomas. Cystic portion of hyp erintensity on nonenhanced T1-weighted images was solely seen in benig n tumors (n = 11). Thus, the highest accuracy (81%) (79% sensitivity a nd 82% specificity) for predicting malignancy was obtained with a crit erion of hypointensity on nonfat-suppressed FSE T2-weighted images plu s absence of cystic portion of hyperintensity on nonenhanced T1-weight ed images. Nonenhanced T1-weighted images combined with nonfat-suppres sed FSE T2-weighted images is optimal for delineation of lesion and pr ediction of pathologic nature of parotid masses. (C) 1997 Elsevier Sci ence Ireland Ltd.