Diffusion tensor imaging of extraocular muscle using two-dimensional single-shot interleaved multiple inner volume imaging diffusion-weighted EPI at 3 tesla.
PURPOSE
To evaluate the feasibility of diffusion tensor imaging (DTI) for the medial and lateral rectus extraocular muscle (EOM) evaluation, to investigate the normal DTI parameters of the medial and lateral rectus EOM, and to compare with other skeletal muscle.


MATERIALS AND METHODS
Seven multiple sclerosis patients and five normal subjects (M:F = 5:7, mean age = 31.6 ± 9.2) without EOM disorder were included. The orbital DTIs using 2D-ss-IMVI-DWEPI were scanned with b = 500 s/mm(2) and 12 directions. The mean diffusivity (MD) and fractional anisotrophy (FA) of medial and lateral rectus EOMs in both orbits, and temporalis muscles were measured in regions of interest on two consecutive axial slices. Student t-test was performed to compare the mean apparent diffusion coefficient and FA values between medial and lateral rectus EOMs, and between EOMs and temporalis muscles.


RESULTS
The MDs in medial (0.58 ± 0.18 × 10(-3) mm(2) /s) and lateral rectus EOMs (0.71 ± 0.18 × 10(-3) mm(2) /s) were significantly lower than temporalis muscle (0.84 ± 0.14 × 10(-3) mm(2) /s) (P < 0.001, respectively). The MD in medial rectus EOM was significantly lower than lateral rectus EOM (P = 0.001). The FAs in medial (0.40 ± 0.05) and lateral rectus EOMs (0.40 ± 0.05) were significantly higher than temporalis muscle (0.25 ± 0.05) (P < 0.001, respectively). There was no significant difference between the FAs in medial and lateral rectus EOMs (P > 0.05).


CONCLUSION
The MDs of EOMs were lower and the FAs were higher than those of skeletal muscle. These are well correlated to the unique characteristics of EOMs.
['Seo|Hyung Suk|HS|', 'Kim|Seong-Eun|SE|', 'Rose|John|J|', 'Hadley|J Rock|JR|', 'Parker|Dennis L|DL|', 'Jeong|Eun-Kee|EK|']
D000293:Adolescent D000328:Adult D000465:Algorithms D056324:Diffusion Tensor Imaging D017352:Echo-Planar Imaging D005260:Female D006801:Humans D007089:Image Enhancement D007090:Image Interpretation, Computer-Assisted D021621:Imaging, Three-Dimensional D008297:Male D008875:Middle Aged D009103:Multiple Sclerosis D009801:Oculomotor Muscles D015203:Reproducibility of Results D012680:Sensitivity and Specificity D055815:Young Adult
diffusion tensor imaging muscle orbit