Multiparametric Quantitative Brain MRI in Neurological and Hepatic Forms of Wilson's Disease

Abstract

Background: In Wilson's disease (WD), demyelination, rarefaction, gliosis, and iron accumulation in the deep gray matter cause opposing effects on T₂ -weighted MR signal. However, the degree and interplay of these changes in chronically treated WD patients has not been quantitatively studied.

Purpose: To compare differences in brain multiparametric mapping between controls and chronically treated WD patients with neurological (neuro-WD) and hepatic (hep-WD) forms to infer the nature of residual WD neuropathology.

Study type: Cross-sectional.

Population/subjects: Thirty-eight WD patients (28 neuro-WD, 10 hep-WD); 26 healthy controls.

Field strength/sequence: 3.0T: susceptibility, T₂ *, T₂ , T₁ relaxometry; 1.5T: T₂ , T₁ relaxometry.

Assessment: The following 3D regions of interest (ROIs) were manually segmented: globus pallidus, putamen, caudate nucleus, and thalamus. Mean bulk magnetic susceptibility, T₂ *, T₂ , and T₁ relaxation times were calculated for each ROI.

Statistical tests: The effect of group (neuro-WD, hep-WD, controls) and age was assessed using a generalized least squares model with different variance for each ROI and quantitative parameter. A general linear hypothesis test with Tukey adjustment was used for post-hoc between-group analysis; P < 0.05 was considered significant.

Results: Susceptibility values were higher in all ROIs in neuro-WD compared to controls and hep-WD (P < 0.001). In basal ganglia, lower T₂ and T₂ * were found in neuro-WD compared to controls (P < 0.01) and hep-WD (P < 0.05) at 3.0T. Much smaller intergroup differences for T₂ in basal ganglia were observed at 1.5T compared to 3.0T. In the thalamus, increased susceptibility in neuro-WD was accompanied by increased T₁ at both field strengths (P < 0.001 to both groups), and an increased T₂ at 1.5T only (P < 0.001 to both groups).

Data conclusion: We observed significant residual brain MRI abnormalities in neuro-WD but not in hep-WD patients on chronic anticopper treatment. Patterns of changes were suggestive of iron accumulation in the basal ganglia and demyelination in the thalamus; 3.0T was more sensitive for detection of the former and 1.5T of the latter abnormality.

Level of evidence: 2 Technical Efficacy Stage: 3 J. Magn. Reson. Imaging 2020;51:1829-1835.

Keywords: Wilson's disease; brain; magnetic resonance imaging; quantitative susceptibility mapping; relaxation time.