Table 2 The major advanced imaging findings in Fabry disease
From: Neuroimaging in Fabry disease: current knowledge and future directions
Advanced imaging findings | ||||
Brain tissue volume | In absence of a severe cerebrovascular pathology, global normalised grey and white matter volumes are preserved in FD patients | A global reduction of the intracranial volume has been observed, suggesting the presence of an abnormal neural development [61] | Voxel-based morphometry studies showed clusters of reduced grey matter density in bilateral thalami and hippocampi [61, 62] | Hippocampal atrophy increases over years, and does not correlate with lesion load [26] |
Diffusion tensor imaging | A diffuse and significant microstructural white matter involvement is present in FD [63] | Elevated total brain parenchymal average diffusion constant has been observed, independent from white matter lesions [64] | Increased mean diffusivity and reduced fractional anisotropy in frontal, parietal and temporal normal-appearing white matter [65, 66] | Voxel-based DTI showed the presence of microstructural damage affecting also the thalamus [67] |
Functional MRI | Significant subtle functional changes seem to occur in FD, independently from major cerebrovascular events [63, 68] | During motor task, FD patients showed increased activation of additional cortical regions [69] | Altered corticostriatal functional connectivity was observed, suggesting a subclinical involvement of motor circuits [68] | Functional changes involve not only the motor, but also cognitive functions, with alterations of the so-called default mode network [63] |
Other MRI techniques | MRI spectroscopy | Magnetisation transfer | Quantitative MRI | MRI Arterial spin labelling |
Inconstant reduction in NAA/Cr ratio in different brain areas, affecting both cortical and subcortical structures [70,71,72] | Reduced magnetisation transfer ratio and bound-pool fraction in the normal-appearing white matter, suggesting a decrease of myelin density [73, 74] | Increased susceptibility values in the striato-nigral pathway of FD patients [75] | Increased cerebral flow in the white matter, with particular reference to the splenium of the corpus callosum [76] | |
Nuclear medicine | Increased relative cerebral blood flow of the posterior and periventricular regions [35] | The altered relative cerebral blood flow seems to reverse after prolonged enzyme replacement therapy [77] | No significant global glucose metabolism changes affects the brain of FD patients [37] | Hypometabolic areas only observed in regions with infarcts or haemorrhages on MRI scans [78] |