MRI Research Today is a free monthly online journal that collates and summarizes the latest research about MRI, including details on magnetic resonance imaging, neuroimaging, brain tumors.

Volumetric MRI and cognitive measures in Alzheimer disease : Comparison of markers of progression.

Ridha BH, Anderson VM, Barnes J, Boyes RG, Price SL, Rossor MN, Whitwell JL, Jenkins L, Black RS, Grundman M, Fox NC

Dementia Research Centre, Institute of Neurology, University College London, 8-11 Queen Square, London, WC1N 3BG, UK, bridha@dementia.ion.ucl.ac.uk.

BACKGROUND : Both cognitive tests and MRI-based measures have been suggested as outcomes in trials assessing disease-modifying therapies in Alzheimer's disease (AD). OBJECTIVE : To compare changes in longitudinal MRI measures with changes in performance on cognitive tests routinely used in AD clinical trials. METHOD : Fifty-two subjects from the placebo-arm of a clinical trial in mild-to-moderate AD had volumetric T(1)-weighted scans and cognitive tests including the Mini-Mental State Examination (MMSE), AD Assessment Scale-Cognitive Subscale, Disability Assessment for Dementia, AD Cooperative Study-Clinical Global Impression of Change and Clinical Dementia Rating at baseline and one-year later. Rates of brain atrophy and ventricular enlargement were measured using the boundary shift integral. Hippocampal (Hc) atrophy was calculated from manual volume measurements. The relationships between MRI and cognitive measures were investigated. RESULTS : Rates of brain atrophy and/or ventricular enlargement were correlated with declining performance on cognitive scales. The strongest association was between brain atrophy rate and MMSE decline (r = 0.59, p < 0.0001). Hc atrophy rate was not significantly correlated with any of the cognitive scales. CONCLUSION : The lack of correlation between Hc atrophy and cognitive scales may reflect a combination of: the extensive functional damage to the Hc by the time AD is clinically established, the greater influence of ongoing cortical degeneration, and errors in Hc outlining. The strong correlations between brain atrophy and ventricular enlargement, and cognitive scales probably reflect the correspondence between these measures of overall cerebral loss and global cognitive measures in the moderate stages of AD.

Published 8 May 2008 in J Neurol, 255(4): 567-74.
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Articles on MRI published 8 May 2008:

Effect of Graded Bicycle Seat Pressure on Perineal Compression: An MRI Analysis.   Br J Sports Med.

OBJECTIVE: To identify a seat pressure threshold that corresponds to significant compression of the perineum. DESIGN: Quasiexperimental crossover. SETTING: Radiology department of a hospital. PARTICIPANTS: A convenience sample of 6 male recreational cyclists. INTERVENTION: Compression of the corpus spongiosum and corpora cavernosa of the perineum without bicycle seat pressure (0) and at 10%, 40%, and 80% of the mean bicycling pressure was assessed using MRI. Seat pressure was applied using a ... [Abstract] [Full-text]

SB 234551 selective ET(A) receptor antagonism: Perfusion/Diffusion MRI used to define treatable stroke model, time to treatment and mechanism of protection.   Exp Neurol.

Mismatches between tissue perfusion-weighted imaging (PWI; an index of blood flow deficit) and cellular diffusion-weighted imaging (DWI; an index of tissue injury) provide information on potentially salvageable penumbra tissue in focal stroke and can identify "treatable" stroke patients. The present pre-clinical studies were conducted to: a.) Determine PWI (using perfusion delay) and DWI measurements in two experimental stroke models, b.) Utilize these measurements to characterize ... [Abstract] [Full-text]

Articles on MRI published 7 May 2008:

Hyperemic flow heterogeneity within the calf, foot, and forearm measured with continuous arterial spin labeling MRI.   Am J Physiol Heart Circ Physiol, 294(5): H2129-36.

Arterial spin labeling (ASL) is a noninvasive magnetic resonance imaging (MRI) technique for microvascular blood flow measurement. We used a continuous ASL scheme (CASL) to investigate the hyperemic flow difference between major muscle groups in human extremities. Twenty-four healthy subjects with no evidence of vascular disease were recruited. MRI was conducted on a 3.0 Tesla Siemens Trio whole body system with a transmit/receive knee coil. A nonmagnetic orthopedic tourniquet system was used ... [Abstract] [Full-text]

Role of FDG-PET in the Clinical Management of Paraneoplastic Neurological Syndrome: Detection of the Underlying Malignancy and the Brain PET-MRI Correlates.   Mol Imaging Biol, 10(3): 131-7.

The role of 2-deoxy-2-[F-18]fluoro-D: -glucose-positron emission tomography (FDG-PET) imaging in the clinical management of paraneoplastic neurological syndrome (PNS) is in evolution. The initial results are promising, and the potential of this modality in this setting has been demonstrated in the literature. In the setting of PNS, FDG-PET imaging can be of value from the following standpoints: (1) detection of the occult malignant focus and (2) objective assessment of the presence and extent ... [Abstract] [Full-text]

The effect of a serotonin-induced dissociation between spiking and perisynaptic activity on BOLD functional MRI.   Proc Natl Acad Sci U S A, 105(18): 6759-64.

The relationship of the blood oxygen-level-dependent (BOLD) signal to its underlying neuronal activity is still poorly understood. Combined physiology and functional MRI experiments suggested that local field potential (LFP) is a better predictor of the BOLD signal than multiunit activity (MUA). To further explore this relationship, we simultaneously recorded BOLD and electrophysiological activity while inducing a dissociation of MUA from LFP activity with injections of the neuromodulator BP554 ... [Abstract] [Full-text]

Articles on MRI published 6 May 2008:

Pharmacological enhancement of disc diffusion and differentiation of healthy, ageing and degenerated discs : Results from in-vivo serial post-contrast MRI studies in 365 human lumbar discs.   Eur Spine J, 17(5): 626-43.

Degenerative disc disease (DDD) is still a poorly understood phenomenon because of the lack of availability of precise definition of healthy, ageing and degenerated discs. Decreased nutrition is the final common pathway for DDD and the status of the endplate (EP) plays a crucial role in controlling the extent of diffusion, which is the only source of nutrition. The vascular channels in the subchondral plate have muscarinic receptors but the possibility of enhancing diffusion pharmacologically ... [Abstract] [Full-text]

A fifteen-year follow-up of neurological conditions in VLBW children without overt disability: Relation to gender, neonatal risk factors, and end stage MRI findings.   Early Hum Dev, 84(5): 343-9.

BACKGROUND:: Very low birthweight (VLBW; birthweight </=1500 g) children run a greater risk than controls of developing neurosensory disabilities, but also minor neurological disturbances. AIMS:: To assess neurological status from the neonatal period up to fifteen years of age in VLBW children without overt neurological disability in relation to gender, neonatal risk factors, and magnetic resonance imaging (MRI) findings of the brain. STUDY DESIGN:: A population based follow-up study of VLBW ... [Abstract] [Full-text]

Convection-enhanced delivery of maghemite nanoparticles: Increased efficacy and MRI monitoring.   Neuro Oncol, 10(2): 153-61.

Convection-enhanced drug delivery (CED) is a novel approach to delivering drugs into brain tissue. Drugs are delivered continuously via a catheter, enabling large volume distributions of high drug concentrations with minimum systemic toxicity. Previously we demonstrated that CED formation/extent of small molecules may be significantly improved by increasing infusate viscosities. In this study we show that the same methodology can be applied to monodispersed maghemite nanoparticles (MNPs). For ... [Abstract] [Full-text]

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