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Purpose: A diffusion-weighted multishot echo-planar imaging approach combined with SENSE and a two-dimensional (2D) navigated motion correction was investigated as an alternative to conventional single-shot counterpart to obtain optic nerve images at higher spatial resolution with reduced artifacts., Methods: Fifteen healthy subjects were enrolled in the study. Six of these subjects underwent a repeated acquisition at least 2 weeks after the initial scan session to address reproducibility. Both single-shot and multishot diffusion tensor imaging studies of the human optic nerve were performed with matched scan time. Effect of subject motions were corrected using 2D phase navigator during multishot image reconstruction. Tensor-derived indices from proposed multishot were compared against conventional single-shot approach. Image resolution difference, right-left optic nerve asymmetry, and test-retest reproducibility were also assessed., Results: In vivo results of acquired multishot images and quantitative maps of diffusion properties of the optic nerve showed significantly reduced image artifacts (e.g., distortions and blurring), and the derived diffusion indices were comparable to those from other studies. Single-shot scans presented larger variability between right and left optic nerves than multishot scans. Multishot scans also presented smaller variations across scans at different time points when compared with single-shot counterparts., Conclusion: The multishot technique has considerable potential for providing improved information on optic nerve pathology and may also be translated to higher fields., (© 2014 Wiley Periodicals, Inc.)

Objective: To investigate differences in T2 intensity of deep gray matter (dGM) structures by magnetic resonance imaging (MRI) in multiple sclerosis (MS) patients undergoing various immunomodulatory therapies., Background: In MS, dGM T2 hypointensities by MRI are hypothesized to represent iron deposition and are known to be associated with worse disease stage as assessed by brain atrophy, cognitive and physical disability. The relation between immunotherapies and T2 intensity, however, has been not been investigated in detail., Methods: A total of 255 MS patients were stratified into those on no treatment (NON, n= 45), and those on immunomodulatory treatments for ≥6 months (ie, interferon beta [IFNβ]n= 118, glatiramer acetate [GA]n= 41, natalizumab [NAT]n= 39, and mycophenolate mofetil [MMF]n= 12). T2 intensities of dentate nucleus (DN), substantia nigra (SN), red nucleus (RN), and globus pallidus (GP) were measured. Group differences in T2 intensities were assessed using a linear regression model with T2 intensities as outcome variable, treatment group as main independent variable, and clinical measures such as Expanded Disability Status Scale (EDSS) score, years of MS, and 25-feet walk time (T25-FW) as covariates. To compare T2 intensities before and after treatment in a subset of NAT-treated patients, we used the Wilcoxon signed-rank test., Results: When adjusted for EDSS, duration of disease and T25-FW, across all deep nuclei, NAT-treated patients had significantly higher T2 intensities than untreated patients (DN p= 1.65 × 10(-5) ; SN p= 2.37 × 10(-5) ; RN p= 3.90 × 10(-6) ; GP p= 1.05 × 10(-6) ), IFNβ-treated patients (DN p= 1.65 × 10(-5) ; SN p= 2.37 × 10(-5) ; RN p= 3.90 × 10(-6) ; GP p= 1.05 × 10(-6) ), and GA-treated patients (DN p= 1.65 × 10(-5) ; SN p= 2.37 × 10(-5) ; RN p= 3.90 × 10(-6) ; GP p= 1.05 × 10(-6) ). In a subset of MS patients receiving NAT, there was a significant increase in T2 intensities in all the dGM nuclei after 24 months of treatment (DN p= 0.00021; SN p= <0.0001; RN p= 0.00015; GP p= 0.00011)., Conclusion: Our preliminary observations suggest that long-term NAT therapy in MS patients may affect T2 intensity levels of dGM brain nuclei, hence suggesting a potential effect of NAT beyond anti-inflammatory effect. Prospective studies are warranted to provide more insights into our preliminary observations. , (Copyright © 2011 by the American Society of Neuroimaging.)