Impact of 3 Tesla MRI on interobserver agreement in clinically isolated syndrome : A MAGNIMS multicentre study

The author(s) disclosed receipt of the following financial support for the research, authorship and/or publication of this article: This research has been supported by a programme grant (14-358e) from the Dutch MS Research Foundation (Voorschoten, The Netherlands). The study in London was supported by the National Institute for Health Research University College London Hospitals Biomedical Research Centre.Background: Compared to 1.5 T, 3 T magnetic resonance imaging (MRI) increases signal-to-noise ratio leading to improved image quality. However, its clinical relevance in clinically isolated syndrome suggestive of multiple sclerosis remains uncertain. Objectives: The purpose of this study was to investigate how 3 T MRI affects the agreement between raters on lesion detection and diagnosis. Methods: We selected 30 patients and 10 healthy controls from our ongoing prospective multicentre cohort. All subjects received baseline 1.5 and 3 T brain and spinal cord MRI. Patients also received follow-up brain MRI at 3-6 months. Four experienced neuroradiologists and four less-experienced raters scored the number of lesions per anatomical region and determined dissemination in space and time (McDonald 2010). Results: In controls, the mean number of lesions per rater was 0.16 at 1.5 T and 0.38 at 3 T (p = 0.005). For patients, this was 4.18 and 4.40, respectively (p = 0.657). Inter-rater agreement on involvement per anatomical region and dissemination in space and time was moderate to good for both field strengths. 3 T slightly improved agreement between experienced raters, but slightly decreased agreement between less-experienced raters. Conclusion: Overall, the interobserver agreement was moderate to good. 3 T appears to improve the reading for experienced readers, underlining the benefit of additional training

Perivascular spaces in MS patients at 7 Tesla MRI: A marker of neurodegeneration?

Background: Virchow-Robin spaces (VRS) are associated with vascular and neurodegenerative disease. In multiple sclerosis (MS), VRS have been associated with neuroinflammation. Ultra-high field imaging may be used to gain insight in these contradictory findings. Objective: The objective of this paper is to analyze VRS in MS patients using high-resolution 7 Tesla (T) MRI. Additionally, we investigated whether the widening of VRS is related to inflammatory or neurodegenerative aspects of MS. Methods: Thirty-four MS patients and 11 healthy controls were examined at 7T. Number and size of VRS were measured on three-dimensional (3D) T1-weighted images, and 3D fluid-attenuated inversion recovery (FLAIR) images were used for MS lesion detection. Brain atrophy was quantified by computing supratentorial brain volume fraction (sBVF). VRS counts were correlated with clinical variables, lesion count and sBVF. Results: MS patients displayed more VRS (median 11) than healthy controls (median four), p = 0.001. VRS size did not differ between both groups. VRS count in MS patients was associated with sBVF (rho = -0.40, p = 0.02), but not with lesion count (p = 0.22). Conclusions: The 7T MRI reveals increased numbers of VRS in MS. The finding that VRS are associated with supratentorial brain atrophy, but not with lesion count, suggests that VRS might rather serve as a neurodegenerative than an inflammatory marker in MS

Improved differentiation between MS and vascular brain lesions using FLAIR* at 7 Tesla

Abstract Objectives To investigate whether a new magnetic resonance image (MRI) technique called T2*-weighted fluid attenuation inversion recovery (FLAIR*) can differentiate between multiple sclerosis (MS) and vascular brain lesions, at 7 Tesla (T). Methods We examined 16 MS patients and 16 age-matched patients with (risk factors for) vascular disease. 3D-FLAIR and T2*-weighted images were combined into FLAIR* images. Lesion type and intensity, perivascular orientation and presence of a hypointense rim were analysed. Results In total, 433 cerebral lesions were detected in MS patients versus 86 lesions in vascular patients. Lesions in MS patients were significantly more often orientated in a perivascular manner: 74 % vs. 47 % (P <0.001). Ten MS lesions (2.3 %) were surrounded by a hypointense rim on FLAIR*, and 24 MS lesions (5.5 %) were hypointense on T2*. No lesions in vascular patients showed any rim or hypointensity. Specificity of differentiating MS from vascular lesions on 7-T FLAIR* increased when the presence of a central vessel was taken into account (from 63 % to 88 %), most obviously for deep white matter lesions (from 69 % to 94 %). High sensitivity remained (81 %). Conclusion 7-T FLAIR* improves differentiation between MS and vascular lesions based on lesion location, perivascular orientation and presence of hypointense (rims around) lesions. Key Points • A new MRI technique T2*-weighted fluid attenuation inversion recovery (FLAIR*) was investigated. • FLAIR* at 7-T MRI combines FLAIR and T2* images into a single image. • FLAIR* at 7 T does not require enhancement with contrast agents. • High-resolution 7-T FLAIR* improves differentiation between MS and vascular brain lesions. • FLAIR* revealed a central vessel more frequently in MS than vascular lesions