Krabbe disease treated with hematopoietic stem cell transplantation: serial assessment of anisotropy measurements--initial experience

PURPOSE: To prospectively compare diffusion-tensor magnetic resonance (MR) imaging anisotropy measurements of white matter (WM) regions in early and late treatment groups of Krabbe disease patients treated with stem cell transplantation. MATERIALS AND METHODS: The study was approved by the Institutional Review Board and was compliant with Health Insurance Portability and Accountability Act; informed consent was obtained from the families of all patients. Patients with early-onset Krabbe disease (four girls and three boys) underwent diffusion-tensor MR imaging before and after stem cell transplantation. Fractional anisotropy (FA) values from serial studies were compared in patients who underwent transplantation at less than 1 month (early group, two girls and one boy) and those who underwent transplantation at 5-8 months (late group, two girls and two boys). FA values were measured in the genu and splenium of the corpus callosum, the frontal WM, and the internal capsule; were compared with those of five age-matched children in the comparison group (normal MR images and no proved neurologic disease); and were expressed as a ratio. Images obtained after transplantation were evaluated at approximately 1 (n = 7), 2 (n = 6), 3 (n = 1), and 4 (n = 1) years. RESULTS: Before transplantation, mean FA ratios in the early group for all four WM regions ranged between 97% and 117%. At 1 year, mean FA ratios at all locations were either 92% or 93%. At 2 years after transplantation, mean FA ratios were between 83% and 92%. In one patient imaged at 3 years, the mean FA ratio was 97%; in another patient imaged at 4 years, the mean FA ratio was 77%. Before transplantation, mean FA ratios in the late group ranged between 55% and 74%. Mean FA ratios were between 37% and 50% at 1 year after transplantation and between 36% and 39% at 2 years. CONCLUSION: All patients had decreases in FA ratios over time. The early group had higher initial FA ratios and lower subsequent decreases, which may indicate amelioration of the dysmyelinating process.