White matter fractional anisotropy correlates with speed of processing and motor speed in young childhood cancer survivors

Purpose: To determine whether childhood medulloblastoma and acute lymphoblastic leukemia (ALL) survivors have decreasedwhite matter fractional anisotropy (WMFA) and whether WMFA is related to the speed of processing and motor speed. Methods and Materials: For this study, 17 patients (6 medulloblastoma, 5 ALL treated with high-dose methotrexate(MTX)(4 � 5g/m 2 )and6withlow-doseMTX (3 � 2g/m 2 ))and17age-matchedcontrolsparticipated.Ona3.0T magnetic resonance imaging (MRI) scanner, diffusion tensor imaging (DTI) was performed, and WMFAvalues were calculated, including specific regions of interest (ROIs), and correlated with the speed of processing and motor speed. Results: Mean WMFA in the patient group, mean age 14 years (range 8.9 ‐ 16.9), was decreased compared with the control group (p= 0.01), as well as WMFA in the right inferior fronto-occipital fasciliculus (IFO) (p=0.03)andinthe genu of the corpus callosum (gCC) (p = 0.01). Based on neurocognitive results, significant positive correlations were present between processing speed and WMFA in the splenium (sCC) (r =0 .53,p = 0.03) and the body of the corpus callosum (bCC) (r =0 .52,p = 0.03), whereas the right IFO WMFAwas related to motor speed (r =0 .49,p < 0.05). Conclusions: Whitemattertracts,usinga3.0-TMRIscanner,showimpairmentinchildhoodcancersurvivors,medulloblastoma survivors, and also those treated with high doses of MTX. In particular, white matter tracts in the sCC,bCC andright IFOarepositivelycorrelatedwithspeedofprocessingand motorspeed. 2009ElsevierInc. DTI, Children, Cancer, Neuropsychology, MTX.