Measurement of Orbital Volume from Facial CT Scans Using a Semi-Automatic Computer Program

ABSTRACT

PURPOSE: To measure the orbital volume from facial CT scans using a semi-automatic computer program. METHODS: Axial and coronal slices of 35 facial CT scans were used to measure the orbital volume. The cross-sectional area was determined from each slice using a semi-automated computer program (MATLAB 2009a). Next, the orbital volume was calculated from serial reconstruction of the cross-sections. RESULTS: The measured value in males was 26.34 +/- 3.09 cm3 in the right orbit and 26.30 +/- 3.21 cm3 in the left orbit from axial scans, and 26.58 +/- 2.76 cm3 in the right orbit and 26.59 +/- 2.75 cm3 in the left orbit from coronal scans. In females, the values were 23.84 +/- 2.29 cm3 in the right orbit and 23.89 +/- 2.33 cm3 in the left orbit from axial scans, and 24.06 +/- 2.90 cm3 in the right orbit and 24.10 +/- 2.82 cm3 in the left orbit from coronal scans. There was high positive correlation (r = +0.832, p = 0.0001) in measured orbital volume between axial and coronal scans. CONCLUSIONS: The orbital volume measurement from facial CT scans using a semi-automatic computer program is very useful. This method should prove useful in further studies examining the correlation of orbital volume variation in many ophthalmologic disorders.