Accuracy and reliability of CBCT imaging for adenoid hypertrophy screening among a sample of oral maxillofacial radiologists and orthodontists and by an automated commercial imaging software

• Author / Creator

  Pereira, Camila P

• Objectives. This thesis project aimed to investigate the diagnostic performance of different dental specialists and a modern dental imaging software to evaluate adenoidal hypertrophy compared with the current reference standard diagnosis by an Otorhinolaryngologist – Head and Neck Surgeon (OHNS) using Nasopharyngoscopy (NP). The specific questions to be answered were: (1) the reliability and accuracy of orthodontists when using Cone-Beam Computer Tomography (CBCT) imaging to evaluate adenoid hypertrophy as compared to the OHNS; (2) the accuracy and reliability of Oral Maxillofacial Radiologists (OMFRs) when evaluating CBCT imaging for adenoid hypertrophy screening as compared with OHNS, and (3) the correlation of volumetric and cross-sectional measurements generated from a CBCT automatic segmentation and 3D reconstruction for evaluating adenoid hypertrophy determined by OHNS. Materials and Methods. A pool of already available CBCT patient heads scans and their respective NP-based adenoid hypertrophy diagnosis were explored for this thesis project. Randomly selected orthodontists from a Canadian city and a significant number of boarded-certified OMFRs from North America were invited to participate. Both specialist samples evaluated 10 CBCT reconstructions via InVivo software viewer and classified the adenoid hypertrophy as mild (0-25%), moderate (26-50%), advanced (51-75%) and severe (higher than 75%). Intraclass Correlation (ICC) and Kappa test were used to test consistency and agreement between participants. These results were later compared to the reference standard diagnosis in an attempt to determine the dental specialists accuracy and reliability. In the last part of this project, 38 scans were reconstructed using Dolphin © Imaging software, which provided automated area and volume measurements of a delimited airway area. This study followed a previously validated method to map the nasopharyngeal area/volume. Two previously trained and calibrated operators applied the standardized method. ICC confirmed their intra- and inter- operator reliability. The capability of the software measurements of volume (mm3) and minimal cross-sectional area (mm2) of the upper airway was correlated with the level of obstruction determined by the OHNS by using Spearman’s Rank Correlation (ρ). Results. Overall, the inter-rater reliability of the fourteen orthodontists was excellent (ICC=0.941; CI 95% = 0.882-0.984). On the contrary, their accuracy against NP was poor (ICCmean= 0.39; ICCrange = 0.00 - 0.74). Their "statistical mode" accuracy, representing the value that appears the most, was moderate (ICC=0.753; CI 95% 0.119-0.937). After that a Kappa (K) test analyzed the data grouped dichotomously, as healthy and unhealthy, and the orthodontists poor accuracy was still confirmed Kmean= 0.44 and Krange= 0.20-0.80. In contrast, the reliability between the thirteen OMFRs were good (ICC=0.79; CI 95% 0.63-0.93). The "statistical mode" was very good (ICC=0.81; ICCrange =0.43-0.94). The accuracy of OMFRs against NP was good, ICCmean= 0.69; 0.43-0.94). In average, the Kmean= 0.77 and Krange= 0.62-0.92 demonstrated a good agreement between the OMFRs and OHNS. The individualized results from each evaluator, Orthodontists and OMFRs, were also presented and investigated according to their performance. The results of the CBCT automatic segmentation and 3D reconstruction software capability showed that intra- and inter-operator reliability was excellent (ICC > 0.95); however, the correlation of the software measurements for both, volume (ρ = -0.222) and minimal cross-sectional area (ρ= 0.192), were weak and not statistically significant. Conclusion. The reliability of Orthodontists and OMFRs (inter-examiner reliability) to classify adenoid hypertrophy on a 4-level scale was excellent and very good, respectively. Both groups of specialists improved when the adenoid hypertrophy was classified dichotomously as healthy/unhealthy and analyzed via Kappa test. Participating orthodontists showed large variability with a poor agreement of the adenoid obstruction degree compared to the OHNS diagnosis (reference standard). The resullts suggested that orthodontists had overall poor diagnostic accuracy for this specific scenario. These findings also suggested that orthodontists were making consistent and systematic errors in their evaluation process. The OMFRs’ reliability was greater than 80% assuring their consistency and accuracy on screening adenoid hypertrophy using CBCT scans. Finally, health professionals should not rely solely on CBCT volumetric and cross-sectional measurements produced by the evaluated automatic reconstruction software to assess an upper airway constriction related to adenoid hypertrophy. The software was reliable, but the generated output for volume and the cross-sectional area did not reflect very well the actual upper airway obstruction determined by the OHNS via NP.

• Subjects / Keywords

  • Adenoid Hypertrophy
  • CBCT
  • Reliability

• Graduation date

  Spring 2016

• Type of Item

  Thesis

• Degree

  Master of Science

• DOI

  https://doi.org/10.7939/R3PZ51V26

• License

  This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.