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Correlation of apparent diffusion coefficient and fractional anisotropy values in the developing infant brain
James M Provenzale1, Jared Isaacson, Steven Chen
1Department of Radiology, Duke University Medical Center, Box 3808, Durham, NC 27710, USA.
Insights
Diffusion tensor imaging (DTI) in infants reveals correlations between apparent diffusion coefficient (ADC) and fractional anisotropy (FA) in white matter (WM) regions. Age significantly influences these relationships, particularly in areas with crossing fibers.
Area of Science:
- Neuroimaging
- Developmental Neuroscience
- Biomedical Engineering
Background:
- Diffusion tensor imaging (DTI) is crucial for assessing white matter (WM) development in infants.
- Apparent diffusion coefficient (ADC) and fractional anisotropy (FA) are key DTI metrics reflecting tissue microstructure.
- Understanding the relationship between ADC and FA in developing WM is vital for diagnosing neurological conditions.
Purpose of the Study:
- To correlate the decrease in apparent diffusion coefficient (ADC) with the increase in fractional anisotropy (FA) in infant white matter (WM) regions.
- To investigate the influence of fiber architecture (crossing vs. parallel) on the ADC-FA relationship.
- To determine the impact of age on these DTI metric correlations.
Main Methods:
- Performed DTI on 53 infants, measuring FA and ADC in 10 critical WM regions.
- Calculated correlation coefficients (r) and coefficients of determination (r²) for ADC as a function of FA.
- Analyzed group data for WM regions with predominantly crossing versus parallel fibers, adjusting for age.
Main Results:
- Significant correlations between FA and ADC were observed across WM regions (r values from -0.81 to -0.50).
- Higher correlations (r²) were found in WM regions with predominantly crossing fibers compared to parallel fibers.
- After age adjustment, correlations persisted, with partial coefficients showing a more even distribution between fiber types.
Conclusions:
- The evolution of FA and ADC in infant WM regions exhibits varying degrees of correlation.
- Infant age exerts a significant influence on the relationship between FA and ADC.
- DTI metrics provide valuable insights into white matter maturation and microstructure.
Objective:
The purpose of our study was to correlate decrease in apparent diffusion coefficient (ADC) and increase in fractional anisotropy (FA) in various white matter (WM) regions using diffusion tenor imaging (DTI) within the first year of life.
Materials And Methods:
We performed DTI on 53 infants and measured FA and ADC within 10 WM regions important in brain development. For each region, we calculated the slope of ADC as a function of FA, the correlation coefficient (r) and correlation of determination (r(2)). We performed a group analysis of r values and r(2)values for six WM regions primarily composed of crossing fibers and four regions primarily having parallel fibers. Upon finding that a strong correlation of FA with age existed, we adjusted for age and calculated partial correlation coefficients.
Results:
Slopes of FA versus ADC ranged from -1.00711 to -1.67592 (p < 0.05); r values ranged from -0.81 to -0.50 and r(2) values from 0.25 to 0.66. The four greatest r(2) values were within WM regions having large numbers of crossing fibers and the three lowest r(2) values were in regions having predominantly parallel fibers. After adjusting for age, slopes ranged from -1.08095 to 0.09612 (p < 0.05 in five cases); partial correlation coefficients ranged from -0.49 to 0.03 and r(2) values from 0.31 to 0.79. The highest partial correlation coefficients were then relatively equally distributed between the two types of WM regions.
Conclusion:
In various regions, FA and ADC evolved with differing degrees of correlation. We found a strong influence of age on the relationship between FA and ADC.
