Cardiac Magnetic Resonance T1 Mapping in Cardiomyopathies

Cardiac magnetic resonance (CMR) imaging has been widely used to assess myocardial perfusion and scar and is the noninvasive reference standard for identification of focal myocardial fibrosis. However, the late gadolinium enhancement (LGE) technique is limited in its accuracy for absolute quantification and assessment of diffuse myocardial fibrosis by technical and pathophysiological features. CMR relaxometry, incorporating T1 mapping, has emerged as an accurate, reproducible, highly sensitive, and quantitative technique for the assessment of diffuse myocardial fibrosis in a number of disease states. We comprehensively review the physics behind CMR relaxometry, the evidence base, and the clinical applications of this emerging technique

Neural mechanisms underlying spatial realignment during adaptation to optical wedge prisms

Visuomotor adaptation to a shift in visual input produced by prismatic lenses is an example of dynamic sensory-motor plasticity within the brain. Prism adaptation is readily induced in healthy individuals, and is thought to reflect the brain’s ability to compensate for drifts in spatial calibration between different sensory systems. The neural correlate of this form of functional plasticity is largely unknown, although current models predict the involvement of parieto-cerebellar circuits. Recent studies that have employed event-related functional magnetic resonance imaging (fMRI) to identify brain regions associated with prism adaptation have discovered patterns of parietal and cerebellar modulation as participants corrected their visuomotor errors during the early part of adaptation. However, the role of these regions in the later stage of adaptation, when ‘spatial realignment’ or true adaptation is predicted to occur, remains unclear. Here, we used fMRI to quantify the distinctive patterns of parieto-cerebellar activity as visuomotor adaptation develops. We directly contrasted activation patterns during the initial error correction phase of visuomotor adaptation with that during the later spatial realignment phase, and found significant recruitment of the parieto-cerebellar network – with activations in the right inferior parietal lobe and the right posterior cerebellum. These findings provide the first evidence of both cerebellar and parietal involvement during the spatial realignment phase of prism adaptation. © 2010 Elsevier Ltd. All rights reserved

Pearls and pitfalls of magnetic resonance imaging of the upper extremity

Magnetic resonance imaging (MRI) is capable of producing images in any anatomical plane, visualizing and analyzing a variety of tissue characteristics, as well as quantifying blood flow and metabolic functions. Although MRI details of compact bone and calcium are poor when compared to those taken with plain radiography or computed tomography, its high soft tissue contrast discrimination and multiplanar imaging capabilities are significant advantages. Musculoskeletal anatomy and neurovascular bundles are well delineated. The advent of MRI has revolutionized the clinician's ability to confirm a proper diagnosis for musculoskeletal problems, which has led to more directed, specific rehabilitative protocols. However, the value of MRI to rehabilitative professionals has been even greater in its ability to identify serious, more uncommon pathologies, such as in those with underlying infection, fracture, or tumor, that require immediate care and are considered to be beyond their scope of practice. Furthermore, MRI, with its precise delineation of fat, muscle, and bone, is an ideal candidate for imaging of muscle disease or injury and has emerged as the method of choice for the detection of early cartilage wear in young patients, such as osteoarthritis. Finally, this imaging modality can avoid radiation exposure in a predominantly younger patient cohort commonly affected by musculoskeletal diseases. The aim of this paper is to consider how physical therapists may take advantage of the diagnostic value of MRI of the upper limb, while avoiding the pitfalls of misinterpretation of images as a result of technical issues, pathological changes, or normal variants

Correlation of quantitative EEG in acute ischemic stroke with 30-day NIHSS score: Comparison with diffusion and perfusion MRI

Background and Purpose-Magnetic resonance imaging (MRI) methods such as diffusion-(DWI) and perfusion-weighted (PWI) imaging have been widely studied as surrogate markers to monitor stroke evolution and predict clinical outcome. The utility of quantitative electroencephalography (qEEG) as such a marker in acute stroke has not been intensively studied. The aim of the present study was to correlate ischemic cortical stroke patients' clinical outcomes with acute qEEG, DWI, and PWI data

Evidence of altered prefrontal-thalamic circuitry in schizophrenia: An optimised diffusion MRI study

MRI diffusion tensor imaging (DTI), optimized for measuring the trace of the diffusion tensor, was used to investigate microstructural changes in the brains of 12 individuals with schizophrenia compared with 12 matched control subjects. To control for the effects of anatomic variation between subject groups, all participants' diffusion images were non-linearly registered to standard anatomical space. Significant statistical differences in mean diffusivity (MD) measures between the two groups were determined on a pixel-by-pixel basis, using Gaussian random field theory. We found significantly elevated MD measures within temporal, parietal and prefrontal cortical regions in the schizophrenia group (P > 0.001), especially within the medial frontal gyrus and anterior cingulate. The dorsal medial and anterior nucleus of the thalamus, including the caudate, also exhibited significantly increased MD in the schizophrenia group (P > 0.001). This study has shown for the first time that MD measures offer an alternative strategy for investigating altered prefrontal-thalamic circuitry in schizophrenia. (c) 2006 Elsevier Inc. All rights reserved

A magnetic resonance imaging investigation of the transversus abdominis muscle during drawing-in of the abdominal wall in elite Australian Football League players with and without low back pain

STUDY DESIGN: Single-blinded quasi-experimental study. OBJECTIVE: To investigate the ability of elite football players with and without low back pain (LBP) to voluntarily draw-in the abdominal wall. BACKGROUND: While there has been considerable debate regarding the contribution of the transversus abdominis (TrA) muscle to control the lumbar spine and pelvis, there is evidence that retraining motor control of the deep trunk muscles is commensurate with decreases in LBP. Magnetic resonance imaging (MRI) has been used to assess the TrA muscle during the draw-in maneuver, with the contraction of the TrA muscle reducing the circumference of the trunk. Impairments in performance of the draw-in maneuver have been shown in people with LBP. METHODS: Forty-three elite players from a team in the Australian Football League were allocated to 3 groups: those with "no LBP," "a history of LBP but no current LBP," or "current LBP." MRI was used to image the cross-sectional area (CSA) of the trunk at the level of the L3-4 disc at the start and end of the draw-in maneuver. RESULTS: There was a significant decrease in the CSA of the trunk with the performance of the draw-in maneuver (