The adenoidal-nasopharyngeal ratio (AN ratio)

The present study disclosed that the AN ratio measured on simple lateral skull radiographs reliably expressed the adenoidal size and patency of the nasopharyngeal airway, and correlated well with the clinical assessment score and the weight of adenoids removed at operation. The inter-observer agreement was satisfactory, and for practical purposes, a value of AN ratio greater than 0.73 may be considered indicative of pathological enlargement of the adenoids. Hopefully this study will facilitate more accurate detection of those children most likely to benefit for adenoidectomy.