Erschienen in:
01.10.2007 | Head and Neck
Diagnostic ability of apparent diffusion coefficients for lymphomas and carcinomas in the pharynx
verfasst von:
Misa Sumi, Yoko Ichikawa, Takashi Nakamura
Erschienen in:
European Radiology
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Ausgabe 10/2007
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Abstract
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/mm2). The ADCs of lymphomas were significantly smaller (0.454 ± 0.075 × 10−3 mm2/s) than those of carcinomas (0.863 ± 0.238 × 10−3 mm2/s). The ADCs of poorly differentiated and undifferentiated carcinomas (0.691 ± 0.149 × 10−3 mm2/s) were significantly smaller than those of moderately differentiated and well-differentiated carcinomas (0.971 ± 0.221 × 10−3 mm2/s), but were significantly larger than those of lymphomas. When an ADC smaller than 0.560 × 10−3 mm2/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.