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Measuring fractional anisotropy of the corpus callosum using diffusion tensor imaging: mid-sagittal versus axial imaging planes.

Kim EY, Park HJ, Kim DH, Lee SK, Kim J - Korean J Radiol (2008 Sep-Oct)

Bottom Line: The FA values obtained from each region were compared between the two sagittal maps.The FA values of the CC were significantly higher on the mid-sagittal DTI than those on the axial DTI in regions I-IV, and particularly in the region IV.Mid-sagittal DTI may provide more accurate FA values of the CC than can the axial DTI, and mid-sagittal DTI may be more desirable for studies that compare between patients and healthy subjects.

View Article: PubMed Central - PubMed

Affiliation: Department of Radiology and the Research Institute of Radiological Science, Yonsei University College of Medicine, Seoul, Korea. eungykim@yuhs.ac

ABSTRACT

Objective: Many diffusion tensor imaging (DTI) studies of the corpus callosum (CC) have been performed with a relatively thick slice thickness in the axial plane, which may result in underestimating the fractional anisotropy (FA) of the CC due to a partial volume effect. We hypothesized that the FA of the CC can be more accurately measured by using mid-sagittal DTI. We compared the FA values of the CC between the axial and mid-sagittal DTI.

Materials and methods: Fourteen healthy volunteers underwent MRI at 3.0 T. DTI was performed in both the mid-sagittal and axial planes. One 5-mm mid-sagittal image and twenty-five 2-mm axial images were obtained for the CC. The five regions of interest (ROIs) that included the prefrontal (I), premotor and supplementary motor (II), motor (III), sensory (IV) and parietal, temporal and occipital regions (V) were drawn along the border of the CC on each sagittal FA map. The FA values obtained from each region were compared between the two sagittal maps.

Results: The FA values of all the regions, except for region V, were significantly increased on the mid-sagittal imaging. The FA values in region IV were significantly underestimated on the mid-sagittal image from the axial imaging, compared with those in the regions I and V (p = 0.037 and p = 0.001, respectively).

Conclusion: The FA values of the CC were significantly higher on the mid-sagittal DTI than those on the axial DTI in regions I-IV, and particularly in the region IV. Mid-sagittal DTI may provide more accurate FA values of the CC than can the axial DTI, and mid-sagittal DTI may be more desirable for studies that compare between patients and healthy subjects.

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Five regions of interest. Prefrontal (I), premotor and supplementary motor (II), motor (III), sensory (IV) and parietal, temporal and occipital regions (V) on mid-sagittal fractional anisotropy (FA) map (A) and the fractional anisotropy map from axial imaging (B).
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Figure 1: Five regions of interest. Prefrontal (I), premotor and supplementary motor (II), motor (III), sensory (IV) and parietal, temporal and occipital regions (V) on mid-sagittal fractional anisotropy (FA) map (A) and the fractional anisotropy map from axial imaging (B).

Mentions: The FA maps were generated using the software installed on the workstation (Version, 1.1.5). The resliced axial images were viewed in the mid-sagittal plane using in-house Windows-based software (Neuroan version 1.0). The five regions of interest (ROIs) consisted of the prefrontal (I), premotor and supplementary motor (II), motor (III), sensory (IV) and the parietal, temporal and occipital regions (V), as suggested by Hofer and Frahm (17). These regions were carefully drawn along the border of the corpus callosum on each sagittal FA map (Fig. 1). The pixels crossing the border of the corpus callosum were eroded manually by using Neuroan. The ROIs were drawn independently by two neuroradiologists, and the average values of the FA from each ROI were used for statistical analysis. We measured the percentage of changes in the FA values between the two sagittal maps.


Measuring fractional anisotropy of the corpus callosum using diffusion tensor imaging: mid-sagittal versus axial imaging planes.

Kim EY, Park HJ, Kim DH, Lee SK, Kim J - Korean J Radiol (2008 Sep-Oct)

Five regions of interest. Prefrontal (I), premotor and supplementary motor (II), motor (III), sensory (IV) and parietal, temporal and occipital regions (V) on mid-sagittal fractional anisotropy (FA) map (A) and the fractional anisotropy map from axial imaging (B).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2627217&req=5

Figure 1: Five regions of interest. Prefrontal (I), premotor and supplementary motor (II), motor (III), sensory (IV) and parietal, temporal and occipital regions (V) on mid-sagittal fractional anisotropy (FA) map (A) and the fractional anisotropy map from axial imaging (B).
Mentions: The FA maps were generated using the software installed on the workstation (Version, 1.1.5). The resliced axial images were viewed in the mid-sagittal plane using in-house Windows-based software (Neuroan version 1.0). The five regions of interest (ROIs) consisted of the prefrontal (I), premotor and supplementary motor (II), motor (III), sensory (IV) and the parietal, temporal and occipital regions (V), as suggested by Hofer and Frahm (17). These regions were carefully drawn along the border of the corpus callosum on each sagittal FA map (Fig. 1). The pixels crossing the border of the corpus callosum were eroded manually by using Neuroan. The ROIs were drawn independently by two neuroradiologists, and the average values of the FA from each ROI were used for statistical analysis. We measured the percentage of changes in the FA values between the two sagittal maps.

Bottom Line: The FA values obtained from each region were compared between the two sagittal maps.The FA values of the CC were significantly higher on the mid-sagittal DTI than those on the axial DTI in regions I-IV, and particularly in the region IV.Mid-sagittal DTI may provide more accurate FA values of the CC than can the axial DTI, and mid-sagittal DTI may be more desirable for studies that compare between patients and healthy subjects.

View Article: PubMed Central - PubMed

Affiliation: Department of Radiology and the Research Institute of Radiological Science, Yonsei University College of Medicine, Seoul, Korea. eungykim@yuhs.ac

ABSTRACT

Objective: Many diffusion tensor imaging (DTI) studies of the corpus callosum (CC) have been performed with a relatively thick slice thickness in the axial plane, which may result in underestimating the fractional anisotropy (FA) of the CC due to a partial volume effect. We hypothesized that the FA of the CC can be more accurately measured by using mid-sagittal DTI. We compared the FA values of the CC between the axial and mid-sagittal DTI.

Materials and methods: Fourteen healthy volunteers underwent MRI at 3.0 T. DTI was performed in both the mid-sagittal and axial planes. One 5-mm mid-sagittal image and twenty-five 2-mm axial images were obtained for the CC. The five regions of interest (ROIs) that included the prefrontal (I), premotor and supplementary motor (II), motor (III), sensory (IV) and parietal, temporal and occipital regions (V) were drawn along the border of the CC on each sagittal FA map. The FA values obtained from each region were compared between the two sagittal maps.

Results: The FA values of all the regions, except for region V, were significantly increased on the mid-sagittal imaging. The FA values in region IV were significantly underestimated on the mid-sagittal image from the axial imaging, compared with those in the regions I and V (p = 0.037 and p = 0.001, respectively).

Conclusion: The FA values of the CC were significantly higher on the mid-sagittal DTI than those on the axial DTI in regions I-IV, and particularly in the region IV. Mid-sagittal DTI may provide more accurate FA values of the CC than can the axial DTI, and mid-sagittal DTI may be more desirable for studies that compare between patients and healthy subjects.

Show MeSH