Diffusion tensor imaging of commissural and projection white matter in tuberous sclerosis complex and correlation with tuber load.
OBJECTIVE
Cortical and white matter changes have been identified outside the MR imaging-visible cortical/subcortical tubers in the tuberous sclerosis complex. The aim of this study was to evaluate DTI changes in the corpus callosum and internal capsules and to correlate the DTI changes with cortical/subcortical tuber load.


METHODS
Twelve TSC patients and 23 controls underwent MR imaging including DTI. FA, trace, D( ||), and D() of genu and splenium of corpus callosum and right and left internal capsules were assessed. The number and volume of cortical/subcortical tubers were correlated with DTI indices of corpus callosum and internal capsules.


RESULTS
In the genu and splenium, FA was lower and trace (P < .01) and D() were higher (P < .01), and in the internal capsules, trace was higher (P = .04) in TSC patients compared with controls. The total tuber volume correlated positively with trace of genu (r = 0.77, P < .01) and splenium (r = 0.69, P = .01) and with D() of splenium (r = 0.68, P = .01), and negatively with FA of splenium (r = -0.60, P = .04) of corpus callosum. The left and right hemispheric tuber volume correlated positively with trace of left (r = 0.56, P = .05) and right (r = 0.67, P = .02) internal capsules.


CONCLUSIONS
Our findings of reduced FA, elevated trace, and elevated D() in the corpus callosum and internal capsules may be related to abnormalities in myelin. The correlations between tuber volume and DTI indices in corpus callosum and internal capsules suggested that more extensive malformation as demonstrated by larger tuber load was more likely to be associated with more severe DTI changes in the commissural and projection white matter.
Simao
G
G
Diagnostic Imaging, Hospital for Sick Children, Toronto, Ontario, Canada.
Raybaud
C
C
Chuang
S
S
Go
C
C
Snead
O C
OC
Widjaja
Elysa
E
D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D003337:Corpus Callosum / Q000473:pathology*; D056324:Diffusion Tensor Imaging; D005260:Female; D006801:Humans; D020772:Internal Capsule / Q000473:pathology*; D008297:Male; D009413:Nerve Fibers, Myelinated / Q000473:pathology; D009434:Neural Pathways / Q000473:pathology; D012720:Severity of Illness Index; D014402:Tuberous Sclerosis / Q000473:pathology*