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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Addis Abeba University


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.



Adenoids,Nasopharyngeal ratio