[Diagnostic value of diffusion-weighted magnetic resonance imaging for solid tumors affecting the base of tongue and glossopharynx].

Purpose: The objective of the present study was to evaluate the potential application value of diffusion-weighted magnetic resonance imaging (DW-MRI) to differentiate solid benign from malignant tumors affecting the base of tongue and glossopharynx.
Methods: Sixty-one patients who presented with solid tumors affecting the base of tongue and glossopharynx underwent conventional MRI and DW-MRI before pathologic verification. Based on pathologic findings, the tumors were classified into 4 groups: Group 1, solid benign tumor (n=10); Group 2, epithelial carcinoma (n=35); Group 3: non- epithelial malignant tumor (n=16); and Group 4: malignant tumor (n=51, a combination of Group 2 and 3). The mean apparent diffusion coefficients (ADCs) were computed from DW-MRI scans obtained with b factors of 0 and 1000 s/mm2. SAS 9.1 software package was used for Wilcoxon test.
Results: The mean ADCs were significantly different (P<0.05) between group 1 and the other 3 groups, and between group 2 and group 3, respectively. Among all kinds of pathological types of lesions, non-Hodgkin lymphoma had a lowest mean ADC value, and schwannoma had a highest mean ADC value. In addition, the mean ADCs among epithelial carcinoma subtypes were not significantly different(P>0.05).
Conclusions: DW-MRI has differential diagnostic value of solid tumors affecting the base of tongue and glossopharynx, especially in distinguishing between benign solid tumors and malignant tumors, and between epithelial carcinomas and non-epithelial malignant tumors.