Sensitive diffusion tensor imaging quantification method to identify language pathway abnormalities in children with developmental delay.

OBJECTIVE: To investigate whether abnormal regional white matter architecture in the perisylvian region could be used as an easy and sensitive quantitative method to demonstrate language pathway abnormalities in children with developmental delay (DD). STUDY DESIGN: We performed diffusion tensor imaging in 15 DD subjects (age, 61.1 ± 20.9 months) and 15 age-matched typically developing (TD) children (age, 68.4 ± 19.2 months). With diffusion tensor imaging color-coded orientation maps, we quantified the fraction of fibers in the perisylvian region that are oriented in anteroposterior (AP) and mediolateral (ML) directions, and their ratio (AP/ML) was calculated. RESULTS: The AP/ML ratio was more sensitive than tractography in characterizing perisylvian regional abnormalities in DD children. The AP/ML ratio of the left perisylvian region was significantly lower in DD children compared with TD children (P = .03). The ML component of bilateral perisylvian regions was significantly higher in DD children compared with TD children (P = .01 [left] and P = .004 [right]). No significant difference was found in the AP component in the two groups. A significant negative correlation of the left ML component with Vineland communication skills was observed (r = -0.657, P = .011). CONCLUSIONS: The AP/ML ratio appears to be a sensitive indicator of regional white matter architectural abnormalities in the perisylvian region of DD children.

Absence of arcuate fasciculus in children with global developmental delay of unknown etiology: a diffusion tensor imaging study.

OBJECTIVE: To investigate cortical association tracts using diffusion tensor imaging (DTI) in children with global developmental delay of unknown etiology. STUDY DESIGN: We performed DTI in 20 patients (age range: 18-83 months, mean: 45 +/- 16 months, 12 males) with a history of global developmental delay and 10 typically developing children (age range: 26-99 months, mean: 54 +/- 24 months, 5 males). DTI tractography was performed to isolate major cortical association tracts. RESULTS: In 9 out of 20 patients, arcuate fasciculus (AF) was absent bilaterally and in another 2 patients, it was absent in left hemisphere. In contrast, AF was present bilaterally in all typically developing children. Fractional Anisotropy (FA) of inferior longitudinal fasciculus (ILF) was asymmetric in the control group but not in the developmental delay group (P = .04). FA was significantly reduced in right ILF in developmentally delayed children compared with controls (P = .03). FA of other association tracts was not different between patients and controls (P = NS). The apparent diffusion coefficient (ADC) showed no asymmetry for these tracts in controls or developmentally delayed children (P = NS). CONCLUSIONS: DTI can be used to identify absence of AF and inadequate maturation of ILF in children with global developmental delay of unknown etiology.