Abstract:
Background: Adenoid hypertrophy is a common clinical condition especially in the
paediatric population. Postnasal space (PNS) x-rays are the imaging modality frequently
used to assess the adenoids. Various objective parameters of assessing adenoid size on
PNS x-ray have been proposed with no agreement on which is most suitable. In this
study, the correlation of two radiographic parameters: adenoidal-nasopharyngeal ratio
(ANR) and antroadenoid diameter (AA diameter) to the volume of adenoid tissues
measured postoperatively will be compared, in order to determine which is more suitable
in assessing the adenoids on postnasal space x-ray.
Objective: To determine and compare the correlation of ANR and AA diameter to
postoperative adenoid volume in order to establish which of the two parameters of
assessing adenoid size on postnasal space x-ray is more suitable.
Methods: This was a cross-sectional study carried out at the Moi Teaching and Referral
Hospital (MTRH) between September 2017 and August 2018. 107 patients aged below
15 years diagnosed with adenoid hypertrophy and scheduled to undergo adenoidectomy
were enrolled. All the x-rays were reviewed by the principal investigator and findings
verified by two consultant radiologists. The postoperative volume of the adenoid tissues
was measured by a trained research assistant. Data were analysed using STATA version
13E. Descriptive statistics were summarized using tables and graphs. Correlation of ANR
and AA diameter to the postoperative adenoid volume was calculated using Pearson‟s
correlation coefficient. Correlation was calculated controlling for the number of days
between the x-ray and surgery which was a potential confounding factor. Comparison of
the two correlation coefficients was carried out using Steiger‟s Z-test.
Results: The age of the participants ranged from 11 months to 11 years; mean of 3.4
years. The mean ANR was 0.70, mean AA diameter was 3.10mm while the mean
postoperative adenoid volume was 2.83mL. Correlation of the ANR to the postoperative
adenoid volume was 0.661(p<0.001) while that of the AA diameter was -0.222
(p=0.022). Null hypothesis was tested using Steiger‟s Z-test and the difference between
the two correlation coefficients found to be significant; the ANR was determined to have
a stronger correlation to adenoid volume than the AA diameter.
Conclusions: The correlation of ANR to postoperative adenoid volume was moderately
positive and statistically significant at 0.661 while that of AA diameter to postoperative
adenoid volume was weak and negative but statistically significant at -0.222. Comparing
the correlation of the two radiographic parameters, the ANR is determined to have a
stronger correlation to the adenoid volume and the difference between the two is
significant. Thus, the ANR is a better predictor of adenoid volume than the AA diameter.
Recommendation: Use of the ANR when reporting PNS x-rays at MTRH.