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Purpose: The R2* relaxation rate constant has been suggested as a sensitive measure for iron accumulation. The aim of this multi-center study was to assess the inter-scanner and inter-subject variability of R2* mapping and to investigate the relationship between brain volume and R2* in specific structures., Methods: R2* mapping was performed in 81 healthy subjects in seven centers using different 3 T systems. R2* was calculated from a dual-echo gradient echo sequence and was assessed in several deep gray matter structures. The inter-scanner and inter-subject variability of R2* was calculated by means of the coefficient of variation before and after correcting for age., Results: Significant center effects were seen in some regions which get lost after age correction. The coefficient of variation for the inter-center variability was much lower (<5.6%) than for the intra-subject variability (6.7%-11.7%). R2* in the putamen and red nucleus scaled with cortical volume while R2* in the globus pallidus and the substantia nigra was negatively associated with white matter volume., Conclusion: R2* is a robust and reproducible measure in a multicenter setting provided that a standardized MRI protocol is used. The relationship between iron concentration in deep gray matter and volume of specific brain compartments needs further investigation., (Copyright © 2013 Wiley Periodicals, Inc.)

Objective: We focused on cerebral imaging findings in a large cohort of young patients with a symptomatic ischemic cerebrovascular event (CVE) to extract relevant pathophysiologic and clinical information., Methods: We analyzed the scans of 2,979 patients (aged 18-55 years) enrolled in the sifap1 project with clinical evidence of ischemic stroke (IS) or clinically defined TIA in whom MRI, including diffusion-weighted imaging, was obtained within 10 days of the CVE. Age groups were categorized as 18-34, 35-44, and 45-55 years. We compared age- and sex-specific proportions of infarct features, white matter hyperintensities, and old microbleeds., Results: Acute infarcts were identified in 1,914 of 2,264 patients (84.5%) with IS and 101 of 715 patients (14.1%) with TIA. Among patients with IS, younger age was significantly associated with acute infarcts in the posterior circulation, while anterior circulation infarcts and acute lacunar infarcts were more frequent in older age groups. One or more old infarcts were present in 26.8% of IS and 17.1% of TIA patients. This rate remained high even after excluding patients with a prior CVE (IS, 21.7%; TIA, 9.9%). The prevailing type of old infarction was territorial in patients younger than 45 years and lacunar in those aged 45 years or older. The frequency of white matter hyperintensities (46.4%) and their severity was positively associated with age. Old microbleeds were infrequent (7.2%)., Conclusions: Young adults show a high frequency of preexisting and clinically silent infarcts and a relative preference for acute ischemia in the posterior circulation. Findings suggesting small-vessel disease become apparent at age 45 years and older.

Background and Purpose: To provide further insight into the MRI assessment of age-related white matter changes (ARWMCs) with visual rating scales, 3 raters with different levels of experience tested the interrater agreement and comparability of 3 widely used rating scales in a cross-sectional and follow-up setting. Furthermore, the correlation between visual ratings and quantitative volumetric measurement was assessed., Methods: Three raters from different sites using 3 established rating scales (Manolio, Fazekas and Schmidt, Scheltens) evaluated 74 baseline and follow-up scans from 5 European centers. One investigator also rated baseline scans in a set of 255 participants of the Austrian Stroke Prevention Study (ASPS) and measured the volume of ARWMCs., Results: The interrater agreement for the baseline investigation was fair to good for all scales (kappa values, 0.59 to 0.78). On the follow-up scans, all 3 raters depicted significant ARWMC progression; however, the direct interrater agreement for this task was poor (kappa, 0.19 to 0.39). Comparison of the interrater reliability between the 3 scales revealed a statistical significant difference between the scale of Manolio and that of Fazekas and Schmidt for the baseline investigation (z value, -2.9676; P=0.003), demonstrating better interrater agreement for the Fazekas and Schmidt scale. The rating results obtained with all 3 scales were highly correlated with each other (Spearman rank correlation, 0.712 to 0.806; P< or =0.01), and there was significant agreement between all 3 visual rating scales and the quantitative volumetric measurement of ARWMC (Kendall W, 0.37, 0.48, and 0.57; P<0.001)., Conclusions: Our data demonstrate that the 3 rating scales studied reflect the actual volume of ARWMCs well. The 2 scales that provide more detailed information on ARWMCs seemed preferential compared with the 1 that yields more global information. The visual assessment of ARWMC progression remains problematic and may require modifications or extensions of existing rating scales.

We performed a prospective multi-centre study using functional magnetic resonance imaging (fMRI) to better characterize the relationships between clinical expression and brain function in patients with multiple sclerosis (MS) at eight European sites (56 MS patients and 60 age-matched, healthy controls). Patients showed greater task-related activation bilaterally in brain regions including the pre- and post-central, inferior and superior frontal, cingulate and superior temporal gyri and insula ( P < 0.05, all statistics corrected for multiple comparisons). Both patients and healthy controls showed greater brain activation with increasing age in the ipsilateral pre-central and inferior frontal gyri ( P < 0.05). Patients, but not controls, showed greater brain activation in the anterior cingulate gyrus and the bilateral ventral striatum ( P < 0.05) with less hand dexterity. An interaction between functional activation changes in MS and age was found. This large fMRI study over a broadly selected MS patient population confirms that movement for patients demands significantly greater cognitive ‘resource allocation’ and suggests age-related differences in brain responses to the disease. These observations add to evidence that brain functional responses (including potentially adaptive brain plasticity) contribute to modulation of clinical expression of MS pathology and demonstrate the feasibility of a multi-site functional MRI study of MS. [ABSTRACT FROM AUTHOR]