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Objective: The potential of magnetization transfer imaging (MTI) and diffusion tensor imaging (DTI) for the detection and evolution of new multiple sclerosis (MS) lesions was analyzed. Methods: Nineteen patients with MS obtained conventional MRI, MTI, and DTI examinations bimonthly for 12 months and again after 24 months at 1.5 T MRI. MTI was acquired with balanced steady-state free precession (bSSFP) in 10 min (1.3 mm3 isotropic resolution) yielding both magnetization transfer ratio (MTR) and quantitative magnetization transfer (qMT) parameters (pool size ratio (F), exchange rate (kf), and relaxation times (T1/T2)). DTI provided fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AD), and radial diffusivity (RD). Results: At the time of their appearance on MRI, the 21 newly detected MS lesions showed significantly reduced MTR/F/kf and prolonged T1/T2 parameters, as well as significantly reduced FA and increased AD/MD/RD. Significant differences were already observed for MTR 4 months and for qMT parameters 2 months prior to lesions' detection on MRI. DTI did not show any significant pre-lesional differences. Slightly reversed trends were observed for most lesions up to 8 months after their detection for qMT and less pronounced for MTR and three diffusion parameters, while appearing unchanged on MRI. Conclusions: MTI provides more information than DTI in MS lesions and detects tissue changes 2 to 4 months prior to their appearance on MRI. After lesions' detection, qMT parameter changes promise to be more sensitive than MTR for the lesions' evolutional assessment. Overall, bSSFP-based MTI adumbrates to be more sensitive than MRI and DTI for the early detection and follow-up assessment of MS lesions. Clinical relevance statement: When additionally acquired in routine MRI, fast bSSFP-based MTI can complement the MRI/DTI longitudinal lesion assessment by detecting MS lesions 2–4 months earlier than with MRI, which could implicate earlier clinical decisions and better follow-up/treatment assessment in MS patients. Key Points: • Magnetization transfer imaging provides more information than DTI in multiple sclerosis lesions and can detect tissue changes 2 to 4 months prior to their appearance on MRI. • After lesions' detection, quantitative magnetization transfer changes are more pronounced than magnetization transfer ratio changes and therefore promise to be more sensitive for the lesions' evolutional assessment. • Balanced steady-state free precession–based magnetization transfer imaging is more sensitive than MRI and DTI for the early detection and follow-up assessment of multiple sclerosis lesions. [ABSTRACT FROM AUTHOR]

Objective: Neuromuscular electrical stimulation (NMES)-induced isometric contraction is feasible during MRI and can be combined with acquisition of volumetric dynamic MR data, in a synchronous and controlled way. Since NMES is a potent resource for rehabilitation, MRI synchronized with NMES presents a valuable validation tool. Our aim was to show how minimal NMES-induced muscle contraction characterization, as evaluated through phase-contrast MRI, differs between senior and young volunteers. Materials and methods: Simultaneous NMES of the quadriceps muscle and phase-contrast imaging were applied at 3 T to 11 senior (75 ± 3 years) and 12 young volunteers (29 ± 7 years). A current sufficient to induce muscle twitch without knee extension was applied to both groups. Results: Strain vectors were extracted from the velocity fields and strain datasets were compared with non-parametric tests and descriptive statistics. Strain values were noticeably different between both groups at both current intensities and significant differences were observed for similar current level. Discussion: In conclusion, NMES-synchronized MRI could be successfully applied in senior volunteers with strain results clearly different from the younger volunteers. Also, differences within the senior group were detected both in the magnitude of strain and in the position of maximum strain pixels. [ABSTRACT FROM AUTHOR]

Introduction: Magnetization transfer (MT) is sensitive to the macromolecular environment of water protons and thereby provides information not obtainable from conventional magnetic resonance imaging (MRI). Compared to standard methods, MT-sensitized balanced steady-state free precession (bSSFP) offers high-resolution images with significantly reduced acquisition times. In this study, high-resolution magnetization transfer ratio (MTR) images from normal appearing brain structures were acquired with bSSFP. Methods: Twelve subjects were studied on a 1.5 T scanner. MTR values were calculated from MT images acquired in 3D with 1.3 mm isotropic resolution. The complete MT data set was acquired within less than 3.5 min. Forty-one brain structures of the white matter (WM) and gray matter (GM) were identified for each subject. Results: MTR values were higher for WM than GM. In general, MTR values of the WM and GM structures were in good accordance with the literature. However, MTR values showed more homogenous values within WM and GM structures than previous studies. Conclusions: MT-sensitized bSSFP provides isotropic high-resolution MTR images and hereby allows assessment of reliable MTR data in also very small brain structures in clinically feasible acquisition times and is thus a promising sequence for being widely used in the clinical routine. The present normative data can serve as a reference for the future characterization of brain pathologies. [ABSTRACT FROM AUTHOR]

In multiple sclerosis (MS) more than 95% of the patients have positive oligoclonal bands (OCB) in the cerebrospinal fluid (CSF). Previous studies have reported differences between patients with and without OCB mainly with regard to clinical parameters such as age, gender, disease duration, and clinical severity. However, several MRI characteristics have also been hypothesized to be distinct, and a varying lesion load in OCB-negative and -positive patients is proposed. In this study, we aimed to evaluate whether Barkhof’s diagnostic MRI criteria are unequally frequently fulfilled in OCB-negative and -positive MS patients. We screened our database for all OCB-negative MS patients who had (1) been treated with the diagnosis of a clinical definite relapsing-remitting MS in our institution as well as (2) undergone CSF analysis and MR brain imaging during hospital stay between January 2004 and December 2007. Eleven OCB-negative patients were identified who fulfilled these criteria. In a second step, we carefully matched each of them to two OCB-positive controls according to age, gender, EDSS, and disease duration. The separate analysis of the several parameters of Barkhof’s criteria revealed a less frequent prevalence of infratentorial (3/11 vs. 18/22; P = 0.005) and a more frequent occurrence of juxtacortical lesions (10/11 vs. 10/22; P = 0.022) in OCB-negative as compared to OCB-positive patients. The overall fulfillment of the Barkhof criteria did not differ in OCB-negative and -positive patients (7/11 vs. 16/22; P = 0.696). Further analyses of MRI findings between OCB-negative and -positive MS patients might contribute to a better pathophysiological understanding of the genesis and evidence of OCB in the CSF of MS patients. [ABSTRACT FROM AUTHOR]

The present experiment investigated the effects of aging on emotional behavior, without concomitant influences from any previous behavioral manipulation apart from weighing the rats. Anxiety-related behaviors were measured in the elevated plus-maze (EPM). Performance in the open field (OF) was also assessed to control for any effect of aging on exploratory behavior that could account for changes in emotional behavior. Fifty-two naïve male Wistar rats of 3 (3MO), 17 (17MO), or 24 (24MO) months, were submitted to two sessions (5 min each) of EPM, followed by two sessions (2 min each) of OF, on 4 consecutive days. The main emotional indices (open arm entries, ratio of open arm entries to total entries, time spent in open arms, ratio of time in open arms to time in four arms, open arm ends, and head dips) measured in the EPM indicated a lower level of anxiety in aged (24MO) than in young (3MO) rats, whereas middle-aged (17MO) rats showed intermediate values between those of 3MO and 24MO rats; 3MO rats showed higher general motor activity (number of rearings in closed arms of EPM and in OF, and higher number of areas crossed in OF) than 17MO and 24MO rats. We conclude that aging is associated with a decrease in anxiety and in general motor activity. [ABSTRACT FROM AUTHOR]

Rats received bilateral stria terminalis (ST) lesions or were sham-operated. Five days later, the animals were trained in a two-way active avoidance task (one session, 30 trials) and, immediately after the training session, received 0.01 mg/kg i.p. epinephrine or distilled water. Retention was tested 20 days after the acquisition session. In sham-operated groups, epinephrine improved retention in rats that were poor learners and impaired it in rats that were good learners. In poor learners with posttraining epinephrine, lesions of the ST not only blocked the facilitatory effect of epinephrine but also disrupted performance throughout the retention session. In good learners, ST lesions attenuated the disruptive effect of epinephrine. Lesions per se did not affect either acquisition or retention. We conclude that ST is involved in the modulatory effect of posttraining epinephrine on memory consolidation. In addition and considering the results observed in rats that were poor learners, we suggest that emotional factors and/or other amygdaloid pathways different from the ST could participate in the effects of posttraining epinephrine, along with the ST. [ABSTRACT FROM AUTHOR]