Application Value Of The Volume Ratio Between Adenoid And Nasopalatine Pharyngeal Cavity Dynamically Determined By Respiratory Gating MR In The Diagnosis And Treatment Of OSAHS In Children

Objective Explore respiration gating MR dynamic determination the volume ratio between adenoid and nasopalatine pharyngeal cavity in children with OSAHS diagnosis significance.Methods Fifty-one children aged from 5 to 12 years-old with an obvious narrow area in the nasopalatine pharyngeal cavity,who were diagnosed as OSAHS by polysomnography(PSG).They all underwent dynamic MR imaging examination that combined with respiratory gating technology in their sleep.At the initial,middle and final stages of their inspiration and expiration,namely six respiratory points,volume of adenoid(Va)and nasopalatine pharyngeal cavity(Vnp)were measured,and then the ratios of Va/Vnp and the linear raitos of adenoid and nasopharynx in the lateral position of head were calculated.Their correlation between the MR parameters from 51 patients and the PSG indexes such as apnea hypoventilation index(AHI)and the lowest oxygen saturation(LaSO2)from 51 patients with OSAHS were analyzed.Results The results from multiple comparisons of any two means of Va/Vnp among the six respiratory stages showed that there were also significant differences apart from the ratios of Va/Vnp between the initial stage of inspiration and the middle stage of expiration,or the final stages of inspiration as well as the initial stages of expiration(All P<0.05).Nevertheless,the ratio of Va/Vnp(69.16±14.19%)at the final stage of expiration was highest.At the six respiratory points,the statistical results on the correlations between the ratios of Va/Vnp and AHI or LaSO2 suggested that there were highly positive correlations between the ratio of Va/Vnp and AHI(All P<0.001).The coefficient of correlation at the final stage of expiration was maximum(r=0.902).There were,however,highly negative correlations between the ratio of Va/Vnp and LaSO2(All P<0.001),and their maximum absolute coefficients of correlation also appeared at the final stage of expiration(r=0.885).There were also highly positive or negative correlations between the A/N and AHI(All,P<0.001)or the A/N and LaSO2(All P<0.001),respectively,and there were the maximum correlations at the final stage of expiration(r=0.561 and r=-0.498,respectively).In addition,the coefficients of correlation between the ratio of Va/Vnp and the AHI or LaSO2 were higher than these between the A/N and AHI or LaSO2.The results from receiver operator characteristic curve(ROC)analysis showed that the area under ROC curve(AUC)of Va/Vnp at the final stage of expiration was 96.6%,and the optimal cut-off point of Va/Vnp between the mild,moderate and severe OSAHS was at about 69.5%.The coincidence rates of which were also up to 84.0%and 88.5%,respectively(Kappa=0.725,P<0.001).Conclusion OSAHS in the pediatric patients with an obvious obstruction of nasopalatine pharyngeal cavity in the upper airway is mainly caused by an abnormal ratio of adenoid and nasopalatine pharyngeal cavity during respiratory movement in their sleep.At the final stage of expiration,the findings showed that the ratio is the most abnormal and the airway obstruction is the most serious.Nonetheless,there is a highly positive correlation between the Va/Vnp and AHI.The ratio of Va/vnp at the final stage of expiration is up to 70%or greater,which provides a basis for clinical imaging diagnosis of severe OSAHS in children with an obstruction of nasopalatine pharyngeal cavity.the Va/Vnp is more accord with the condition of OSAHS severity classification than the ratio of A/N.MR imaging combined with respiratory gating technology has higher practical application value in the diagnosis and treatment of OSAHS in pediatric patients.