Change of white matter integrity in children with hematopoietic stem cell transplantation

Abstract Background Advances of hematopoietic stem cell transplantation has improved the survival rate of malignant diseases and congenital immunodeficiencies. It has become important to assess long-term complications in survivors. To assess CNS abnormalities in children treated by transplantation, diffusion tensor imaging (DTI) was performed before and after transplantation. Methods Forty children who underwent head DTI before and after their first transplantation were enrolled. Patients with CNS lesions on conventional MRI were excluded. Fractional anisotropy (FA) and mean diffusivity (MD) were compared between patients and 28 controls using tract-based spatial statistics (TBSS). The Strengths and Difficulties Questionnaire was administered as a behavioral evaluation after transplantation, and DTI of patients with and without behavioral abnormalities was compared. Results The median age of patients and controls was 4.5 years (0-19 years) and 4.5 years (0-16 years), respectively. The diagnosis was solid tumor, bone marrow failure, leukemia, primary immunodeficiency syndrome, and others. The date of DTI was 10-57 days before transplantation and 40-153 days after transplantation. TBSS showed FA reduction in widespread white matter in patients before and after transplantation compared to controls. MD was high before transplantation and normalized after transplantation. Analysis comparing before and after HSCT shows no difference in FA, and significantly high MD before HSCT. In patients with behavioral abnormalities, low FA and high MD remained after transplantation. Conclusions Longitudinal DTI showed white matter abnormalities in children without conventional MRI abnormalities, that were related to behavioral problems after transplantation. DTI is useful for behavioral assessment in children undergoing transplantation.