title: Assessment of parotid masses: which MR pulse sequences are optimal?
abstract: The objective of this paper is to determine which MR pulse sequences are 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 contrast-to-noise ratios were measured. On visual assessment, detection sensitivity was 100% for nonenhanced nonfat-suppressed T1-weighted images, 91% for nonfat-suppressed fast spin-echo (FSE) T2-weighted images, 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. Hypointensity of lesion relative to the parotid gland on nonfat-suppressed FSE T2-weighted images was seen in 11 of 14 malignancies, 12 of 15 Warthin tumors, and two of 18 pleomorphic adenomas. Cystic portion of hyperintensity on nonenhanced T1-weighted images was solely seen in benign tumors (n = 11). Thus, the highest accuracy (81%) (79% sensitivity and 82% specificity) for predicting malignancy was obtained with a criterion of hypointensity on nonfat-suppressed FSE T2-weighted images plus absence of cystic portion of hyperintensity on nonenhanced T1-weighted images. Nonenhanced T1-weighted images combined with nonfat-suppressed FSE T2-weighted images is optimal for delineation of lesion and prediction of pathologic nature of parotid masses.
authors.affiliation: Department of Radiology, Shinshu University School of Medicine, Matsumoto, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Takashima
authors.forename: S
authors.initials: S
authors.lastname: Sone
authors.forename: F
authors.initials: F
authors.lastname: Takayama
authors.forename: Y
authors.initials: Y
authors.lastname: Maruyama
authors.forename: M
authors.initials: M
authors.lastname: Hasegawa
authors.forename: A
authors.initials: A
authors.lastname: Horii
authors.forename: J
authors.initials: J
authors.lastname: Yoshida
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D010306:Parotid Gland / Q000473:pathology*; D010307:Parotid Neoplasms / Q000473:pathology*; D011446:Prospective Studies; D012680:Sensitivity and Specificity