No abstract

In vivo MRI provides a means to non-invasively image and assess the morphological features of atherosclerotic carotid arteries. To assess quantitatively the degree of vulnerability and the type of plaque, the contours of the lumen, outer boundary of the vessel wall and plaque components, need to be traced. Currently this is done manually, which is time-consuming and sensitive to inter- and intra-observer variability. The goal of this work was to develop an automated contour detection technique for tracing the lumen, outer boundary and plaque contours in carotid MR short-axis black-blood images. Seventeen patients with carotid atherosclerosis were imaged using high-resolution in vivo MRI, generating a total of 50 PD- and T1-weighted MR images. These images were automatically segmented using the algorithm presented in this work, which combines model-based segmentation and fuzzy clustering to detect the vessel wall, lumen and lipid core boundaries. The results demonstrate excellent correspondence between automatic and manual area measurements for lumen (r = 0.92) and outer (r = 0.91), and acceptable correspondence for fibrous cap thickness (r = 0.71). Though further optimization is required, our algorithm is a powerful tool for automatic detection of lumen and outer boundaries, and characterization of plaque in atherosclerotic vessels.

Objective: The aim of this study was to ascertain whether high-dose intravenous (IV) iron sucrose could improve symptoms and change brain iron concentrations in idiopathic RLS. Methods:The study was a randomized, parallel-group double-blind study of 1000 mg iron sucrose given IV versus placebo. Primary measures of the clinical status were global rating scale (GRS) and periodic leg movements of sleep (PLMS). Primary measures of brain iron status were CSF ferritin and MRI-determined iron in the substantia nigra.Results: At the time of the interim analysis there were 7 placebo and 11 iron-treated subjects. At 2-weeks post-treatment, iron treatment resulted in a small but significant increase in CSF ferritin and decrease in RLS severity (GRS) but did not change PLMS or MRI iron index. None of the secondary outcomes changed with treatment. There was no single case of clear treatment benefit in any of the patients. This interim analysis revealed an effect size that was too small to allow for adequate power to find significant differences with the planed 36-subject enrollment for either the primary objective outcome of PLMS or any of the secondary outcomes. The study was stopped at this planned breakpoint given the lack of both adequate power and any indication for clinically significant benefit.Conclusions: High-dose IV iron failed to demonstrate the robust changes reported in three prior open-label studies. Differences in iron formulation, dosing regiment, and peripheral iron status may explain some of the discrepancies between this and previous IV iron treatment studies.

Background and Purpose HIV-associated dementia (HAD) has been extensively studied using magnetic resonance spectroscopy (MRS) at field strengths of 1.5 Tesla (T). Higher magnetic field strengths (such as 3T) allow for more reliable determination of certain compounds, such as glutamate (Glu) and glutamine (Gln). The current study was undertaken to investigate the utility of 3T MRS for evaluating HIV+ patients with different levels of cognitive impairment with emphasis on the measurement of Glu and Glx (the sum of Glu and Gln). Methods Eighty six HIV+ subjects were evaluated at 3T using quantitative short echo time single voxel MRS of frontal white matter (FWM) and basal ganglia (BG). Subjects were divided into 3 groups according to the Memorial Sloan Kettering (MSK) HIV dementia stage: 21 had normal cognition (NC) (MSK 0), 31 had mild cognitive impairment (MCI) without dementia, (clinical MSK stage = 0.5) and 34 had dementia (HAD) (MSK > 1). HIV+ subjects had also undergone standardized cognitive testing covering the domains of executive function, verbal memory, attention, information processing speed, and motor and psychomotor speed. Between group differences in metabolite levels in FWM and BG were evaluated using ANOVA. Pearson correlation coefficients were used to explore the associations between the Glu and Glx metabolites and neurocognitive (NP) results. Results FWM Glx (combined Glu and Gln) was lower in HAD (8.1±2.1 mM) compared to both the MCI (9.17±2.1 mM) and NC groups (10.0±1.6 mM), (P = 0.006). FWM myo-inositol (mI) was higher in HAD (4.15±0.75 mM) compared to both MCI (3.86±0.85 mM) and NC status (3.4±0.67 mM), (P = 0.006). FWM Glx/Creatine (Cr) was lower and FWM mI/Cr significantly higher in the HAD compared to MCI and NC groups (P = 0.01) and (P = 0.004) respectively. BG NAA was lower in the HAD group (6.79±1.53 mM), compared to the MCI (7.5±1.06 mM), and NC groups (7.6±1.01 mM), (P = 0.036). Significant negative correlations were observed between Glu, Glx, and NAA concentrations with Trail-making test B (P= 0.006, 0.0001, and 0.007 respectively) and significant positive correlation was found with Digit symbol test (P= 0.02, 0.002, and 0.008 respectively). FWM Glx and NAA concentrations showed negative correlation with Grooved pegboard non-dominant hand (P= 0.02 and 0.04 respectively). Conclusion Patients with HAD have lower levels of Glx concentrations and Glx/Cr ratio in FWM, which was associated with impaired performance in specific cognitive domains, including executive functioning, fine motor, attention and working memory performance. 3T MRS measurements of Glx may be a useful indicator of neuronal loss/dysfunction in patients with HIV infection.