Diffusion weighted imaging of nasopharyngeal adenoid hypertrophy.

Abstract

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. To identify and to analyse DWI findings of NAH. 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). 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)). 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.