Three-dimensional segmentation of the upper airway using cone beam CT: a systematic review

Abstract

The objectives of this study were to systematically review the literature for studies that used cone beam CT (CBCT) to automatically or semi-automatically model the upper airway (including the pharyngeal, nasal and paranasal airways), and to assess their validity and reliability. Several electronic databases (MEDLINEH, MEDLINE In-Process & Other NonIndexed Citations, all evidence-based medicine reviews including the Cochrane database, and Scopus) were searched. Abstracts that appeared to meet the initial selection criteria were selected by consensus. The original articles were then retrieved and their references were searched manually for potentially suitable articles that were missed during the electronic search. Final articles that met all the selection criteria were evaluated using a customized evaluation checklist. 16 articles were finally selected. From these, five scored more than 50% based on their methodology. Although eight articles reported the reliability of the airway model generated, only three used intraclass correlation (ICC). Two articles tested the accuracy/validity of airway models against the gold standard, manual segmentation, using volumetric measurements; however, neither used ICC. Only three articles properly tested the reliability of the three-dimensional (3D) upper airway model generated from CBCT and only one article had sufficiently sound methodology to test the airway model's accuracy/validity. The literature lacks proper scientific justification of a solid and optimized CBCT protocol for airway imaging. Owing to the limited number of adequate studies, it is difficult to generate a strong conclusion regarding the current validity and reliability of CBCT-generated 3D models.

Palatal volume and area assessment on digital casts generated from cone-beam computed tomography scans

“…Moreover, it may not be comparable between consecutive records because two reference planes have been selected to measure preand postvolumes without reorienting the casts. [21][22][23] One additional method was based on geometric measurements performed by tracing and dividing the palatal space into small sections with regular shapes used to calculate area and volume geometrically. 9 However, it followed straight lines and not the irregular surface, generating geometric shapes and lines that may not represent exactly the actual structural anatomy of the palate.…”

Strategies for Segmenting the Upper Airway in Cone-Beam Computed Tomography (CBCT) Data

“…Manual feature segmentation of medical scan data is a laborious and time-consuming task, and there is a demand for an accurate segmentation methods which are either automatic, or require less user input [52]. The accuracy and versatility of the few existing automatic and semi-automatic methods, are under-researched.…”

“…Alsufyani et al [52] systematically reviewed the three-dimensional segmentation of the upper airway using CBCT, and noted the lack of a reliable and opti- …”

Topical contrast agents to improve soft-tissue contrast in the upper airway using cone beam CT: a pilot study

“…2 Adding to the difficulty is the complex anatomy of the nasal airway, which will affect boundary definition, grey-level thresholding, accuracy of the 3D model and any resultant quantitative analysis. 3 Contrast agents are employed by many imaging modalities and can easily improve signal-to-noise ratio by improving tissue contrast. Several studies used contrast agents, namely iodine, in the nasal and paranasal sinuses to assess nasal/sinus drug delivery using MDCT, 4,5 nuclear medicine [6][7][8] and CBCT.…”