Investigating the reliability and reproducibility of nasal anthropometry using three-dimensional digital stereophotogrammetry

Li, Zhouxiao (2021): Investigating the reliability and reproducibility of nasal anthropometry using three-dimensional digital stereophotogrammetry. Dissertation, LMU München: Medizinische Fakultät

Abstract

Three-dimensional Surface Imaging (3DSI) becomes an established method for anthropometric measurements and is applied in a variety of medical disciplines, for example, in the analysis of infant facial development, in the analysis of congenital conditions such as cleft lip and palate or alterations of the skull, in facial reconstructive surgery, and for aesthetic facial plastic surgery consultation. As a non-invasive technology, it plays an increasingly important role in evaluating facial morphology and is often used in support of radiation-intensive CT imaging or expensive MRI imaging. 3DSI of the face provides detailed measurements including distances, curvatures, volumes, angles, and surface areas. Previous studies have shown considerable reliability in the application of 3DSI for the planning and follow-up in rhinoplasty and craniomaxillofacial surgery. Compared to the validated data in the extensive literature on the periorbital region, there is a lack of validated data for 3D acquisition in the nose area. Therefore, more independent verification of the 3D derived measurements is necessary. The present thesis aims to lay the foundation for extensive application of the novel 3D digital nasal anthropometry by evaluating its reliability and reproducibility. In this study, standardized 3DSI of 160 volunteers (80 European Caucasian and 80 Asians) was performed using an established Vectra 3D imaging system. Two raters 3D-imaged the volunteers' facial regions in separate sessions repeatedly. 46 soft-tissue landmarks were determined, and their 138 coordinates were recorded in three spatial planes (x-y-z axis). 57 corresponding projective linear dimensions, surface distances, angles and facial ratios were evaluated for the reliability of intra-rater, inter-rater, and intra-method. Statistical analysis for the reliability was done through mean absolute difference (MAD), relative error measurement (REM), technical error of measurement (TEM), relative technical error of measurement (rTEM), and intraclass correlation coefficient (ICC). 57 corresponding projective linear dimensions, surface distances, angles and facial ratios were evaluated for the reliability of intra-rater, inter-rater, and intra-method.Statistical analysis for the reliability was done through mean absolute difference (MAD), relative error measurement (REM), technical error of measurement (TEM), relative technical error of measurement (rTEM), and intraclass correlation coefficient (ICC). Overall, the 46 landmarks and the anthropometry based on them are highly comparable in this study. The reproducibility for 138 coordinates in 160 samples distribute as follows: intra-rater: < 0.5 mm (45%), < 1 mm (42%), > 1 mm (13%); inter-rater: < 0.5 mm (31.2%), < 1 mm (42%), >1 mm (26.8%).The reproducibility of landmarks in the nasal tip region is slightly different between Caucasians and Asians. The landmarks in the lip and chin area of males are more reproducible compared with females generally. However, there is no difference in the reproducibility ranking of landmarks by genders. Furthermore, all 57 measurements display a good reliability with ICC above 0.75. Of these, 41 measurements show excellent reliability with ICC larger than or equal to 0.9. The MAD is less than 0.3 mm for most straight-line distances. All the MAD of angles are smaller than 0.3 degree. The MAD is less than 0.01 for ratio measurements except for Nostril Aspect Ratio left (0.013). 50 measurements of estimates for the relative error magnitude were less than 1%. All of rTEM estimates were of very good reliability.

• Dokumententyp: Dissertationen (Dissertation, LMU München)
• Keywords: 3D surface imaging, nasal anthropometry, facial landmarks，reliability, reproducibility
• Themengebiete: 600 Technik, Medizin, angewandte Wissenschaften ; 600 Technik, Medizin, angewandte Wissenschaften > 610 Medizin und Gesundheit
• Fakultäten: Medizinische Fakultät
• Sprache der Hochschulschrift: Englisch
• Datum der mündlichen Prüfung: 15. Dezember 2021
• 1. Bericht­erstatter:in: Giunta, Riccardo