Diagnostic ability of apparent diffusion coefficients for lymphomas and carcinomas in the pharynx.
We evaluated the diagnostic ability of diffusion-weighted imaging for the differentiation between lymphomas and carcinomas in the pharynx and between carcinomas with different histological types in the pharynx. T1-weighted, fat-suppressed T2-weighted, and diffusion-weighted MR imaging was performed on 14 patients with pharyngeal lymphomas, 26 patients with carcinomas of the pharynx, 5 patients with adenoidal hypertrophy, and 22 patients with normal tonsils. Apparent diffusion coefficients (ADCs) were determined by using two b factors (500 and 1,000 s/mm(2)). The ADCs of lymphomas were significantly smaller (0.454 +/- 0.075 x 10(-3) mm(2)/s) than those of carcinomas (0.863 +/- 0.238 x 10(-3) mm(2)/s). The ADCs of poorly differentiated and undifferentiated carcinomas (0.691 +/- 0.149 x 10(-3) mm(2)/s) were significantly smaller than those of moderately differentiated and well-differentiated carcinomas (0.971 +/- 0.221 x 10(-3) mm(2)/s), but were significantly larger than those of lymphomas. When an ADC smaller than 0.560 x 10(-3) mm(2)/s was used for predicting lymphomas, we obtained the highest accuracy of 96%, with 100% sensitivity and 94% specificity, 86% positive predictive value, and 100% negative predictive value. Therefore, ADC measurements effectively differentiate lymphomas from carcinomas in the pharynx and could be a useful adjunct to biopsy-based development of treatment planning.
Sumi
Misa
M
Department of Radiology and Cancer Biology, Nagasaki University School of Dentistry, Nagasaki, Japan.
Ichikawa
Yoko
Y
Nakamura
Takashi
T
D000328:Adult; D000368:Aged; D002294:Carcinoma, Squamous Cell / Q000175:diagnosis*; D003937:Diagnosis, Differential; D038524:Diffusion Magnetic Resonance Imaging; D005260:Female; D006801:Humans; D016393:Lymphoma, B-Cell / Q000175:diagnosis*; D008297:Male; D008875:Middle Aged; D010610:Pharyngeal Neoplasms / Q000175:diagnosis*