Future of functional brain imaging

In the mind's eye: provider and patient attitudes on functional brain imaging

Success in functional neuroimaging has brought the promise of quantitative data in the form of brain images to the diagnosis of disorders of the central nervous system for which only qualitative clinical criteria have previously existed. Even though the translation of research to clinical neuroimaging for conditions such as major depression may not be available yet, rapid innovation along this trajectory of discovery to implementation compels exploration of how such information will eventually affect providers and patients. Clinical neuroethics is devoted to elucidating ethical challenges prior to and during the transfer of new research capabilities to the bedside. Through a model of proactive ethics, clinical neuroethics promotes the development of responsible social and public policies in response to new diagnostic and prognostic capabilities for the benefit of patients and their families, and for providers within the health care systems in which they practice. To examine views about the potential interaction of clinical neuroimaging and depression, we surveyed both mental health providers and outpatients and inpatients diagnosed with major depressive disorder. From responses of 52 providers and 72 patients, we found high receptivity to brain scans for treatment tailoring and choice, for improving understanding of and coping with disease, and for mitigating the effects of stigma and self-blame. Our results suggest that, once ready, roll out of the fully validated technology has significant potential to reduce social burden associated with highly stigmatized illnesses like depression.

The future of magnetic resonance-based techniques in neurology

Magnetic resonance techniques have become increasingly important in neurology for defining: 1. brain, spinal cord and peripheral nerve or muscle structure; 2. pathological changes in tissue structures and properties; and 3. dynamic patterns of functional activation of the brain. New applications have been driven in part by advances in hardware, particularly improvements in magnet and gradient coil design. New imaging strategies allow novel approaches to contrast with, for example, diffusion imaging, magnetization transfer imaging, perfusion imaging and functional magnetic resonance imaging. In parallel with developments in hardware and image acquisition have been new approaches to image analysis. These have allowed quantitative descriptions of the image changes to be used for a precise, non-invasive definition of pathology. With the increasing capabilities and specificity of magnetic resonance techniques it is becoming more important that the neurologist is intimately involved in both the selection of magnetic resonance studies for patients and their interpretation. There is a need for considerably improved access to magnetic resonance technology, particularly in the acute or intensive care ward and in the neurosurgical theatre. This report illustrates several key developments. The task force concludes that magnetic resonance imaging is a major clinical tool of growing significance and offers recommendations for maximizing the potential future for magnetic resonance techniques in neurology.

On the characteristics of functional magnetic resonance imaging of the brain

In this review we discuss various recent topics that characterize functional magnetic resonance imaging (fMRI). These topics include a brief description of MRI image acquisition, how to cope with noise or signal fluctuation, the basis of fMRI signal changes, and the relation of MRI signal to neuronal events. Several observations of fMRI that show good correlation to the neurofunction are referred to. Temporal characteristics of fMRI signals and examples of how the feature of real time measurement is utilized are then described. The question of spatial resolution of fMRI, which must be dictated by the vascular structure serving the functional system, is discussed based on various fMRI observations. Finally, the advantage of fMRI mapping is shown in a few examples. Reviewing the vast number of recent fMRI application that have now been reported is beyond the scope of this article.

Fractal analysis--a new approach in brain receptor imaging

Improvements in detector technology and the development of radioligands for brain receptor imaging have introduced exiting new insights into the pathophysiology of various neuropsychiatric disorders and have improved the possibilities of optimizing the treatment for patients suffering from them. Positron emission tomography (PET) and single-photon emission tomography (SPET) with tailored radiopharmaceuticals provide information on the topographic physiological chemistry of the living human brain. The different patterns of brain receptor densities and distribution can be imaged and modelled with PET and SPET. The normal receptor distribution in the brain is broadly heterogeneous with different cortical layers, which show receptor densities varying from very low to high. Further exploration of the data shows that human neurophysiology and neural architectures possess fractal properties that may be altered during activation and in different neuropsychiatric disorders. This review highlights recent findings in SPET receptor imaging and the use of fractal analysis in the interpretation of images representing various neuropsychiatric disorders.