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FIG 2. Anterior aspects of an image section obtained in an 23-year-old man show white matter tracts superimposed on images A–F magnified from the rectangular region-of-interest (solid rectangles). Partial volume effects near adjacent CSF lead to underestimation of FA in the genu of the corpus callosum on conventional DTI (left column and dashed rectangles in E.) Note the less consistent fiber directions and the darker gray level, which indicates lower FA values. These effects account for the smaller amount of fibers found with the tracking algorithm on conventional DTI than on FLAIR DTI (right column, dashed rectangles in F). Note the more consistent fiber directions and the brighter gray level, which indicates higher FA values.
A and B, Images obtained with b = 0 s/mm2 by using the EZ-tracing algorithm.
C and D, FA maps in gray scale displayed in the identical window level.
E and F, Vector-encoded FA maps. Red indicates left-right; green, anteroposterior; and blue, superoinferior.
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