Quantitation of zygomatic complex symmetry using 3-dimensional computed tomography.

Area of Science:

• Medical Imaging
• Craniofacial Anatomy
• Surgical Planning

Background:

• Zygomatic complex (ZMC) symmetry is crucial for facial aesthetics and function.
• Accurate clinical evaluation of ZMC symmetry is challenging with traditional methods.
• 3D computed tomography (CT) offers advanced visualization for craniofacial analysis.

Purpose of the Study:

• To develop and validate a novel 3D CT-based method for measuring zygomatic complex (ZMC) eminence and width.
• To assess the accuracy and reproducibility of this new method for evaluating ZMC symmetry.
• To compare the new method's performance against traditional landmark-based measurements.

Main Methods:

• Spiral CT scans were acquired from 50 volunteers with visually symmetric faces.
• A 3D coordinate system was established based on the craniofacial midsagittal plane.
• Measurements of ZMC eminence (ΔE) and width (ΔW) were taken, with comparisons to traditional eminence measurements (ΔcE).

Main Results:

• The new method showed significantly lower asymmetry values (ΔE: 0.6 mm) compared to traditional methods (ΔcE: 1.75 mm; P < .001).
• High reliability was observed for the new method, with intraclass correlation coefficients (ICCs) indicating almost perfect agreement for inter- and intra-examiner measurements (ΔE: 0.82-0.86, ΔW: 0.81-0.85).
• Traditional methods demonstrated only moderate agreement (ICC: 0.61-0.68).

Conclusions:

• The novel 3D CT method provides a practical and valuable tool for precise clinical evaluation of zygomatic complex (ZMC) symmetry.
• This technique enhances accuracy and reproducibility in assessing facial asymmetry.
• The findings support the clinical utility of advanced imaging for craniofacial assessments.