Evaluation of the examiner reliabilities of lower border planes used for volumetric measurement of pharyngeal airway

The aim of this study is to assess the intra-examiner and inter-examiner reliabilities of different lower border planes used for volumetric measurement of oropharyngeal airway in CBCT. The study consists of CBCT scans of 35 skeletal Class I subjects (mean age: 18,9±3,4years). The volume from each scan was measured by using four commons used lower airway borders on Dolphin 3D software (Dolphin Imaging and Management Solutions, Chatsworth, California). Three researchers with different levels of experience independently made volumetric measurements twice with two week interval. With keeping all other variables constant, oropharyngeal airway volumes measured four times for each scan with the most anterior and inferior point of second cervical vertebrae(CV2ai), the most anterior and inferior point of third cervical vertebrae(CV3ai), tip of epiglottis(EP) and tip of soft palate(SP) as lower limit. The intraclass correlation coefficient (ICC) was used to assess intra-examiner and inter-examiner reliabilities. Repeatability coefficients (RC) for each 4 parameters were calculated by using interexaminer, intraexaminer and total variance components in the repetitive measurement design. As a result of statistical analysis reliability was found excellent (ICC ≥ 0.9) for all measured variants. Narrowest confidence interval and highest Repeatability for both interexaminer and intraexaminer measurements found in CV2 which fallowed by CV3, SP and EP respectively. According to the findings of our study although there is no big differences in reliability of all these borders, bony structures has higher repeatability than soft tissue ones. Due to the standardization need for the data of pharyngeal airway studies a consensus should be achieved. Keywords: CBCT, Oropharyngeal airway, Reliability