Assessment of pediatric adenoid size and adenoid-to nasopharyngeal ratio using conventional CT at tikur anbesa specialized hospital (tash), addis abeba, Ethiopia (Prospective cross sectional study).
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Date
2019-09
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Addis Abeba University
Abstract
Background information: Many studies have been developed revealing normal measurements
of adenoid size and adenoid to nasopharyngeal Ratio (ANR). The lateral radiograph is a common
investigative modality. However, the literature is diverse and controversial. Lateral x-rays
undertaken for purposes other than suspected upper airway way obstruction at Tikur Anbessa
Specialized Hospital (TASH) are assumed to be inadequate for the sample size needed for this
study. Moreover, the risk of radiation exposure makes the use of lateral x–ray requests solely for
this study unethical. Therefore a cross-sectional imaging study was done.
Objective: To determine the accurate size of the mean adenoidal size and ANR
Methodology: A quantitative prospective cross-sectional study was conducted in 114 patients
aged from 4-12 years (divided into three age groups), who underwent CT of the neck or head &
neck at Tikur Anbessa Specialized Hospital (TASH), Addis Ababa, Ethiopia. Subjects who had
symptoms of upper airway obstruction or sleep-disordered breathing were excluded objectively
using Obstructive Sleep Apnea score (OSA). Linear measurements of adenoid size and
nasopharyngeal depth were done along a reconstructed sagittal section and the ANR was
calculated according to the Fujioka method.
Results:
We studied 114 children aged 4-12 years who were divided into three sub-groups namely group I
(4-6 yrs), II (7-9 yrs) and III (10-12yrs). We calculated the mean adenoid thickness, mean
nasopharyngeal depth and calculated the mean ANR of each groups. The statistically analyzed
mean ANRs were 0.416, 0.397 and 0.395 for Group I, II, and III respectively with the highest
value of 0.66 detected in group I. The mean adenoid size were measured to be 8.34, 8.41, and
9.42 for the age groups I, II and III respectively. We found that both the mean adenoid size and
the ANR did not show significant differences between each groups but there was a progressive
increase of the nasopharyngeal depth as the age progress across the different groups.
Conclusion:
Adenoid to nasopharyngeal ratio (ANR) was the most consistent radiologic parameter when
subjectively compared with previous x-ray based studies. Therefore we strongly recommend the
use of ANR rather than the mere use of the adenoid size or the nasopharyngeal space depth
particularly when evaluating the degree of nasopharyngeal obstruction by enlarged adenoids.
However radiologists and responsible physicians should use lateral x-rays cautiously as plain
films may overestimate or underestimate the adenoid shadow and nasopharyngeal space depth
due to superimposition of adjacent structures.
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Keywords
Adenoids,Nasopharyngeal ratio