Magnetic Susceptibility Changes in the Basal Ganglia and Brain Stem of Patients with Wilson's Disease: Evaluation with Quantitative Susceptibility Mapping.

Objectives: Wilson's disease (WD) is characterized with the accumulation of copper in the liver and brain. The objective of this study is to quantitatively measure the susceptibility changes of basal ganglia and brain stem of pediatric patients with neurological WD using quantitative susceptibility mapping (QSM) in comparison to healthy controls.
Methods: Eleven patients with neurological WD (mean age 15 ± 3.3 years, range 10-22 years) and 14 agematched controls were prospectively recruited. Both groups were scanned on a 1.5 Tesla clinical scanner. In addition to T ₁ - and T ₂ -weighted MR images, a 3D multi-echo spoiled gradient echo (GRE) sequence was acquired and QSM images were derived offline. The quantitative measurement of susceptibility of corpus striatum, thalamus of each hemisphere, midbrain, and pons were assessed with the region of interest analysis on the QSM images. The susceptibility values for the patient and control groups were compared using twosample t-test.
Results: One patient with WD had T ₁ shortening in the bilateral globus pallidus. Another one had hyperintensity in the bilateral putamen, caudate nuclei, and substantia nigra on T ₂ -weighted images. The rest of the patients with WD and all subjects of the control group had no signal abnormalities on conventional MR images. The susceptibility measures of right side of globus pallidus, putamen, thalamus, midbrain, and entire pons were significantly different in patients compared to controls (P < 0.05).
Conclusion: QSM method exhibits increased susceptibility differences of basal ganglia and brain stem in patients with WD that have neurologic impairment even if no signal alteration is detected on T ₁ - and T ₂ -weighted MR images.