The Role of MR Imaging in the Assessment of Clinical Outcomes in Children with X-Linked Adrenoleukodystrophy after Allogeneic Haematopoietic Stem Cell Transplantation.

Background: The aim of the study was to analyse MR images of the brain, including advanced MR techniques, such as single voxel spectroscopy (MRS) and diffusion tensor imaging (DTI), in children with X-linked adrenoleukodystrophy (X-ALD) before and after haematopoietic stem cell transplantation (HSCT) and to establish the imaging criteria which may be helpful in the assessment of disease staging, qualification to HSCT and follow-up.

Material/methods: Seven boys, aged 5-10 years, (mean 8.14 years) with biochemically proved X-ALD, underwent plain MR imaging with a 1.5 T unit before and after HSCT. Structural images were analyzed using an MRI severity scale (Loes scale). In one patient the follow-up examinations included MRS with the assessment of metabolite ratios (NAA/Cr, Cho/Cr, mI/Cr), as well as DTI with evaluation of fractional anisotropy (FA) and apparent diffusion coefficient (ADC) in several white matter tracts.

Results: Two boys had an MRI severity score before HSCT equal to <8 points, and after HSCT they showed no clinical or radiological progression. In 5 patients with a higher severity score (from 8 to 16 points, mean 10.9) before HSCT, clinical and radiological progression was observed (MRI severity score from 17 to 25 points, mean 20.9). Follow-up advanced MRI techniques in one boy showed metabolic alterations, as well as decreased FA and ADC values in all evaluated areas.

Conclusions: Children at an early stage of X-ALD (below 8 points in MRI severity scale) are more likely to benefit from HSCT. DTI and MRS seem to be more useful imaging methods to assess the progression of X-ALD.