Diffusion weighted imaging of nasopharyngeal adenoid hypertrophy.

BACKGROUND: Diffusion-weighted imaging (DWI) could be helpful for the differentiation of malignant and benign entities. Nasopharyngeal adenoid hypertrophy (NAH) is a typical benign lesion. DWI appearances of this lesion have not been reported previously.
PURPOSE: To identify and to analyse DWI findings of NAH.
MATERIAL AND METHODS: We analyzed 688 MR investigations of the head performed at our institution. Magnetic resonance imaging (MRI) was obtained at a 1.5 T MRI device. Beside normal standard sequences DWI was obtained using a multislice single-shot echo-planar sequence. DWI was performed with b values of 0, 500, and 1000 s/mm(2).
RESULTS: The mean whole lesion ADC value was 0.83 ± 0.12 × 10(-3) mm(2) s(-1) (median, 0.82 × 10(-3) mm(2) s(-1); range, 0.58-1.45 × 10(-3) mm(2) s(-1)). The mean ADC value of solid areas of NAH was 0.59 ± 0.11 × 10(-3) mm(2) s(-1) (range, 0.36-0.84 × 10(-3) mm(2) s(-1)).
CONCLUSION: Although NAH is a benign lesion, it shows low ADC values both in childhood and in adults. This finding should be kept in mind to avoid possible misinterpretations as a malignant lesion. © The Foundation Acta Radiologica 2014 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.