Browsing by Author "Damjanovic, Dusan (59572798100)"

Purpose: To study the concomitant use of structural and functional magnetic resonance (MR) imaging correlates to explain information processing speed (IPS) and executive function (EF) in multiple sclerosis (MS). Materials and Methods: Local ethics committee approval was obtained at all sites for this prospective, multicenter study. All subjects provided written informed consent. Twenty-six patients with relapsing-remitting MS and 32 healthy control subjects from four centers underwent structural and functional MR imaging, including a go/no-go task and neuropsychological assessment. Subtests of the Brief Repeatable Battery of Neuropsychological Tests, the Wisconsin Card Sorting Test, and the performance with the functional MR imaging paradigm were used as estimates of IPS and EF. Activation of the thalamus and the inferior frontal gyrus (pars triangularis), thalamic volume, T2 lesion load, and age were used to explain IPS and EF in regression models. Results: Compared with control subjects, patients showed increased activation in a frontoparietal network, including both thalami, during the execution of the go/no-go task. Patients had decreased thalamic volume (P , .001). Among tested variables, thalamic volume (b = 0.606, P = .001), together with thalamic activation (b = 20.410, P = .022), were the best predictors of IPS and EF and helped explain 52.7% of the variance in IPS and EF. Conclusion: This study highlights the potential of the combined use of functional and morphologic parameters to explain IPS and EF in patients with relapsing-remitting MS and confirms the central role of the thalamus as a relay station in executive functioning. © RSNA, 2016.

Objective: To apply voxel-based methods to map the regional distribution of atrophy and T2 hyperintense lesions in the cervical cord of multiple sclerosis (MS) patients with different clinical phenotypes. Methods: Brain and cervical cord 3D T1-weighted and T2-weighted scans were acquired from 31 healthy controls (HC) and 77 MS patients (15 clinically isolated syndromes (CIS), 15 relapsing-remitting (RR), 19 benign (B), 15 primary progressive (PP) and 13 secondary progressive (SP) MS). Hyperintense cord lesions were outlined on T2-weighted scans. The T2- and 3D T1-weighted cord images were then analysed using an active surface method which created output images reformatted in planes perpendicular to the estimated cord centre line. These unfolded cervical cord images were co-registered into a common space; then smoothed binary cord masks and lesion masks underwent spatial statistic analysis (SPM8). Results: No cord atrophy was found in CIS patients versus HC, while PPMS had significant cord atrophy. Clusters of cord atrophy were found in BMS versus RRMS, and in SPMS versus RRMS, BMS and PPMS patients, mainly involving the posterior and lateral cord segments. Cord lesion probability maps showed a significantly greater likelihood of abnormalities in RRMS, PPMS and SPMS than in CIS and BMS patients. The spatial distributions of cord atrophy and cord lesions were not correlated. In progressive MS, regional cord atrophy was correlated with clinical disability and impairment in the pyramidal system. Conclusions: Voxel-based assessment of cervical cord damage is feasible and may contribute to a better characterisation of the clinical heterogeneity of MS patients.