Measurement of Orbital Volume from Different Slice Thickness Facial Computed Tomography Scans Using a Semi-automatic Program

PURPOSE: To compare the orbital volume calculated from various slice thickness facial computed tomography scans using a semi-automated computer program. METHODS: Axial and coronal scans of 2, 2.5, 3 mm slice thickness facial computed tomography 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®, MathWorks, Inc., Natick, MA, USA), and then the volume was calculated from serial reconstruction of the cross sections. RESULTS: The measured value in the 2 mm images was 33.14 ± 2.37 cm³ in the right orbit and 34.32 ± 2.60 cm³ in the left orbit for the axial scans, and 35.54 ± 3.58 cm³ in the right orbit and 34.96 ± 4.05 cm³ in the left orbit for the coronal scans. In the 2.5 mm images, the values were 33.28 ± 3.35 cm³ in the right orbit and 33.73 ± 4.10 cm³ in the left orbit for the axial scans, and 35.24 ± 3.98 cm³ in the right orbit and 35.10 ± 3.93 cm³ in the left orbit for the coronal scans. In the 3 mm images, the values were 33.23 ± 2.70 cm³ in the right orbit and 33.39 ± 2.69 cm³ in the left orbit for the axial scans, and 33.20 ± 3.64 cm³ in the right orbit and 32.95 ± 3.45 cm³ in the left orbit for the coronal scans. In the 3 mm image, there was not a significant difference in the calculated volume between the axial and coronal scans (p(3mm) = 0.62). CONCLUSIONS: Because there is no difference in the results of the orbital volumetric measurements between three other slice thicknesses in the axial scan, using axial scan images with a computer program that semi-automatically calculates orbital volume is useful. In addition, the volume measured by thick slice images has more reproducibility than the volume measured by thin slice images.

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

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.

Orbital Wall Reconstruction by Copying a Template(defect model) from the Facial CT in Blow-out Fracture

PURPOSE: Recently, orbital wall fracture is common injuries in the face. Facial CT is essential for the accurate diagnosis and appropriate treatment to reconstruct of the orbital wall. The objective of this study was to report the method for accurate measurement of area and shape of the bony defect in the blow-out fractures using facial CT in prior to surgery. METHODS: The authors experienced 46 cases of orbital wall fractures and examined for diplopia, sensory disturbance in the area of distribution of the infraorbital nerve, and enophthalmos in the preoperation and followed 1 months after surgery, from August 2007 to May 2008. Bony defect was predicted by measuring continuous defect size from 3mm interval facial CT. Copying from the defect model(template), we reconstructed orbital wall with resorbable sheet(Inion CPS(R), Inion Oy, Tampere, Finland). RESULTS: One months after surgery using this method, 26(100%) of the 26 patients improved in the diplopia and sensory disturbance in the area of distribution of the infraorbital nerve. Also 8(72.7%) of the 11 patients had enophthalmos took favorable turn. CONCLUSION: This accurate and time-saving method is practicable for determining the location, shape and size of the bony defect. Using this method, we can reconstruc

Orbital Wall Reconstruction by Copying a Template(defect model) from the Facial CT in Blow-out Fracture

PURPOSE: Recently, orbital wall fracture is common injuries in the face. Facial CT is essential for the accurate diagnosis and appropriate treatment to reconstruct of the orbital wall. The objective of this study was to report the method for accurate measurement of area and shape of the bony defect in the blow-out fractures using facial CT in prior to surgery. METHODS: The authors experienced 46 cases of orbital wall fractures and examined for diplopia, sensory disturbance in the area of distribution of the infraorbital nerve, and enophthalmos in the preoperation and followed 1 months after surgery, from August 2007 to May 2008. Bony defect was predicted by measuring continuous defect size from 3mm interval facial CT. Copying from the defect model(template), we reconstructed orbital wall with resorbable sheet(Inion CPS(R), Inion Oy, Tampere, Finland). RESULTS: One months after surgery using this method, 26(100%) of the 26 patients improved in the diplopia and sensory disturbance in the area of distribution of the infraorbital nerve. Also 8(72.7%) of the 11 patients had enophthalmos took favorable turn. CONCLUSION: This accurate and time-saving method is practicable for determining the location, shape and size of the bony defect. Using this method, we can reconstruc