Deep grey matter T2 hypo-intensity in patients with paediatric multiple sclerosis

Objective: T2 hypo-intensity on magnetic resonance imaging scans is thought to reflect pathological iron deposition in the presence of disease. In this pilot study, we evaluated the utility of the quantification of T2 hypo-intensities in paediatric patients by estimating deep grey matter (DGM) T2 hypo-intensities in paediatric patients with multiple sclerosis (MS) or clinically isolated syndromes (CIS), and their changes over 1 year. Methods: A dual-echo sequence was obtained from 45 paediatric patients (10 with CIS, 35 with relapsing-remitting MS, 8 with an onset of the disease before the age of 10 and 37 during adolescence) and 14 age-matched healthy controls (HC). Eleven patients were reassessed both clinically and with MRI after 1 year. Normalized T2 intensity in the basal ganglia and thalamus was quantified. Results: At baseline, DGM T2 intensity was similar between paediatric patients and HC in all the structures analysed, except for the head of the left caudate nucleus (p = 0.001). DGM T2 intensity of the head of the left caudate nucleus was similar between paediatric CIS and RRMS patients, but it was reduced in adolescent-onset paediatric patients versus HC (p = 0.002). In all patients, DGM T2 intensity of the head of the left caudate nucleus was correlated with T2 lesion volume (r = -0.39, p = 0.007). DGM T2 intensity in all the structures analysed with longitudinal assessment remained stable over the follow-up in the cohort of patients. Conclusions: The quantification of DGM T2 intensity in paediatric patients may provide surrogate markers of neurodegeneration. In paediatric MS, DGM is likely to be affected by iron-related changes, which are likely to be, at least partially, secondary to WM damage.