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Few data were available for the understanding of olfactory function in neuromyelitis optica spectrum disorders (NMOSDs). The aims of our study were to investigate the incidence of olfactory dysfunction and characterize olfactory structures, using MRI, in patients with NMOSDs. Olfactory function was evaluated by olfactometer in 49 patients with NMOSDs and 26 matched healthy controls. MRI parameters such as olfactory bulb (OB) and the olfactory-related gray matter volume changes were assessed. The frequency of olfactory dysfunction was 53% in patients with NMOSDs. Olfactory detection thresholds were positively correlated with serum aquaporin-4 antibodies (fluorescent units) tested by fluorescent immunoprecipitation assay (FIPA) in NMOSDs (p = 0.009). Patients with olfactory dysfunction had smaller OB volume than did patients without olfactory dysfunction or controls (p0.01). Both detection and recognition thresholds for olfaction were negatively correlated with OB volume (p = 0.018, p0.01). The significant gray matter volume reduction in NMOSDs was found in the bilateral piriform cortex, orbitofrontal cortex, and parahippocampal gyri (FDR correction, p0.05, cluster size200 voxels). Our data suggested that olfactory function deficits are prevalent in patients with NMOSDs. Reduced OB and olfactory-related cortex volume may be responsible for the olfactory dysfunction.

Recently, a new MRI technique was developed at 3 Tesla (T), called fluid attenuated inversion recovery* (FLAIR*). In this study, we implemented FLAIR* in an existing MS cohort at 7 T, to investigate whether we could corroborate results of previous 7 T studies that introduced specific MS lesion characteristics. Furthermore, we aimed to investigate the meaning of these lesion characteristics by relating them to clinical characteristics of the MS patient. Three-dimensional FLAIR and T2*-weighted images of 33 MS patients and 7 healthy controls were fused into FLAIR* images. Lesion type, signal intensity and morphology were analysed on FLAIR*, side-by-side with the original FLAIR and T2*, and correlated with clinical characteristics using Spearman’s rho. Three morphological features of MS lesions were visualised: (1) central vessel (CV) within lesions, present in 78 % of total MS lesions; (2) hypointense rims around MS lesions, present in eight patients; (3) FLAIR* lesions that were hypointense at T2*, present in 13 patients. The presence of hypointense (rims around) lesions was not related to clinical characteristics. The simultaneous presence of rimlike lesions and hypointense lesions within MS patients was significantly correlated (ρ = 0.52, P

Focal lesions and brain atrophy are the most extensively studied aspects of multiple sclerosis (MS), but the image acquisition and analysis techniques used can be further improved, especially those for studying within-patient changes of lesion load and atrophy longitudinally. Improved accuracy and sensitivity will reduce the numbers of patients required to detect a given treatment effect in a trial, and ultimately, will allow reliable characterization of individual patients for personalized treatment. Based on open issues in the field of MS research, and the current state of the art in magnetic resonance image analysis methods for assessing brain lesion load and atrophy, this paper makes recommendations to improve these measures for longitudinal studies of MS. Briefly, they are (1) images should be acquired using 3D pulse sequences, with near-isotropic spatial resolution and multiple image contrasts to allow more comprehensive analyses of lesion load and atrophy, across timepoints. Image artifacts need special attention given their effects on image analysis results. (2) Automated image segmentation methods integrating the assessment of lesion load and atrophy are desirable. (3) A standard dataset with benchmark results should be set up to facilitate development, calibration, and objective evaluation of image analysis methods for MS. © 2012 The Author(s).