Questionable accuracy of CBCT in determining bone density: A comparative CBCT-CT in vitro study.

Area of Science:

• Radiology
• Dental Imaging
• Biomedical Engineering

Background:

• The accuracy of radiological bone density estimation using cone-beam computed tomography (CBCT) grayscale values remains uncertain.
• Standardization and correlation with computed tomography (CT) Hounsfield units (HU) are necessary before widespread clinical adoption.

Purpose of the Study:

• To evaluate the reliability of CBCT grayscale for bone density estimation.
• To assess the clinical utility of CBCT grayscale by comparing it with CT HU in samples with intact soft tissue.

Main Methods:

• 240 sites from 20 goat heads were scanned using both CBCT and CT.
• Bone mineral density was measured using HU in CT and grayscale in CBCT, preserving soft tissue anatomy.
• Statistical analysis included Cronbach's alpha, Pearson's correlation, t-tests, and regression analysis.

Main Results:

• Statistically significant differences were found between CBCT grayscale and CT HU means (p=0.000).
• Correlation coefficients were weak (0.496 for mean, 0.037 for min, 0.396 for max).
• Regression analysis showed low R-squared values (29.79% for mean, 21.05% for min, 19.45% for max).

Conclusions:

• CBCT grayscale demonstrates a weak positive correlation with CT HU for bone density estimation.
• The low predictive reliability of CBCT grayscale indicates its questionable clinical applicability compared to standard CT HU.