Ultrahigh field MRI in clinical neuroimmunology: a potential contribution to improved diagnostics and personalised disease management

Conventional magnetic resonance imaging (MRI) at 1.5 Tesla (T) is limited by modest spatial resolution and signal-to-noise ratio (SNR), impeding the identification and classification of inflammatory central nervous system changes in current clinical practice. Gaining from enhanced susceptibility effects and improved SNR, ultrahigh field MRI at 7 T depicts inflammatory brain lesions in great detail. This review summarises recent reports on 7 T MRI in neuroinflammatory diseases and addresses the question as to whether ultrahigh field MRI may eventually improve clinical decision-making and personalised disease management

Temperature dependence of the coercive field in single-domain particle systems

The magnetic properties of Cu97Co3 and Cu90Co10 granular alloys were measured over a wide temperature range (2 to 300K). The measurements show an unusual temperature dependence of the coercive field. A generalized model is proposed and explains well the experimental behavior over a wide temperature range. The coexistence of blocked and unblocked particles for a given temperature rises difficulties that are solved here by introducing a temperature dependent blocking temperature. An empirical factor gamma arise from the model and is directly related to the particle interactions. The proposed generalized model describes well the experimental results and can be applied to other single-domain particle system.Comment: 7 pages, 8 figures, revised version, accepted to Physical Review B on 29/04/200

7T MRI in natalizumab-associated PML and ongoing MS disease activity: a case study

OBJECTIVE: To assess the ability of ultra-high-field MRI to distinguish early progressive multifocal leukoencephalopathy (PML) from multiple sclerosis (MS) lesions in a rare case of simultaneous presentation of natalizumab-associated PML and ongoing MS activity. METHODS: Advanced neuroimaging including 1.5T, 3T, and 7T MRI with a spatial resolution of up to 0.08 mm(3) was performed. RESULTS: 7T MRI differentiated between PML-related and MS-related brain damage in vivo. Ring-enhancing MS plaques displayed a central vein, whereas confluent PML lesions were preceded by punctate or milky way-like T2 lesions. CONCLUSIONS: Given the importance of early diagnosis of treatment-associated PML, future systematic studies are warranted to assess the value of highly resolving MRI in differentiating between early PML- and MS-induced brain parenchymal lesions

Determination of closure domain penetration in electrodeposited microtubes by combined magnetic force microscopy and giant magneto-impedance techniques

The domain structure of electrodeposited Co90P10 microtubes exhibiting radial magnetic anisotropy and giant magneto-impedance effect has been characterized by combined magnetic force microscopy imaging and impedance measurements. It has been shown that the size of the closure domains increases with the CoP layer thickness. Furthermore, the depth of the closure domains has been quantitatively determined from the high frequency behavior.The authors want to thank Professor J. Miltat for helpful discussions. This work has been performed under Project No. CAM/07N/0033/1998. A. Asenjo would like to thank the CAM (Spain) for the postdoctoral fellowship. J. P. Sinnecker thanks the Brazilian agencies CNPq and FAPERJ for the financial support.Peer reviewe

Neuromyelitis optica does not impact periventricular venous density versus healthy controls: a 7.0 Tesla MRI clinical study

Objective: To quantify the periventricular venous density in neuromyelitis optica spectrum disease (NMOSD) in comparison to that in patients with multiple sclerosis (MS) and healthy control subjects. Materials and methods: Sixteen patients with NMOSD, 16 patients with MS and 16 healthy control subjects underwent 7.0-Tesla (7T) MRI. The imaging protocol included T2*-weighted (T2*w) fast low angle-shot (FLASH) and fluid-attenuated inversion recovery (FLAIR) sequences. The periventricular venous area (PVA) was manually determined by a blinded investigator in order to estimate the periventricular venous density in a region of interest-based approach. Results: No significant differences in periventricular venous density indicated by PVA were detectable in NMOSD versus healthy controls (p = 0.226). In contrast, PVA was significantly reduced in MS patients compared to healthy controls (p = 0.013). Conclusion: Unlike patients with MS, those suffering from NMOSD did not show reduced venous visibility. This finding may underscore primary and secondary pathophysiological differences between these two distinct diseases of the central nervous system