Microstructural Changes in Normal-Appearing White Matter in Pediatric X-Linked Adrenoleukodystrophy: A Diffusion Tensor Imaging Study

Objective: Diffusion tensor imaging (DTI) is an advanced magnetic resonance imaging (MRI) technique that provides quantitative diffusion data of water molecules in tissue. Usage of DTI in pediatric X-linked adrenoleukodystrophy (X-ALD) may adjunct earlier detection of brain involvement. This study aimed to analyze the normal-appearing white matter in pediatric patients with X-ALD using DTI. Materials and Methods: A retrospective database search was performed. Children with genetically diagnosed X-ALDs with a reportedly normal brain MRI between January 2010 and September 2021 were included. Fractional anisotropy (FA), radial diffusivity (RD), axial diffusivity (AD), and apparent diffusion coefficient were serially measured in 8 regions of the brain, and these measurements were compared with those in control patients. Results: The study group included 21 X-ALD patients and 11 control patients. The mean age was 6.64 ± 5.14 years. FA values of the genu and body of the corpus callosum were significantly lower in the ALD group than controls. There was also a statistically significant difference in FA, AD, and RD values of cerebellar white matter in the two groups. Conclusion: There is evidence of white matter damage on DTI in X-ALD patients with the normal-appearing white matter on conventional MRI sequences. The inclusion of DTI in routine MRI examinations of X-ALD patients may provide additional insight into possible white matter damage in that population.