Optical Imaging of Brain Function and Metabolism

. . . . . At last the doctor will be freed from the tedious interpretation of screens and photographs. Instead, he will examine and scan through his patient directly. Wearing optical-shutter spectacles and aiming a pulsed laser torch, he will be able to peer at the beating heart, study the movement of a joint or the flexing of a muscle, press on suspect areas to see how the organs beneath respond, check that pills have been correctly swallowed or that an implant is savely in place, and so on. A patient wearing white cotton or nylon clothes that scatter but hardly absorb light, may not even have to undress . . . . .. David Jones, Nature (1990) 348:290 Optical imaging of the brain is a rapidly growing field of heterogenous techniques that has attracted considerable interest recently due to a number of theoretical advantages in comparison with other brain imaging modalities: it uses non­ ionizing radiation, offers high spatial and temporal resolution, and supplies new types of metabolic and functional information. From a practical standpoint it is important that bedside examinations seem feasible and that the implementations will be considerably less expensive compared with competing techniques. In October 1991, a symposium was held at the Eibsee near Garmisch, Germany to bring together the leading scientists in this new field.

Inhalt

Near Infrared Spectroscopy of the Brain.- NMR and time-resolved optical studies of brain imaging.- Wavelength dependence of the differential pathlength factor and the log slope in time-resolved tissue spectroscopy.- Towards human brain near infrared imaging: Time resolved and unresolved spectroscopy during hypoxic hypoxia.- Measurement of human hypothermic cerebral oxygen metabolism by transmission spectroscopy.- Optical CT imaging of hemoglobin oxygen-saturation using dual-wavelength time gate technique.- Optical properties of normal human intracranial tissues in the spectral range of 400 to 2500 nm.- Imaging of Brain Function Using Intrinsic Signals.- Optical imaging of the functional architecture in cat visual cortex: The layout of direction and orientation domains.- Mapping of neural activity patterns using intrinsic optical signals: From isolated brain preparations to the intact human brain.- Fiber optic imaging of subcortical neural tissue in freely behaving animals.- Olfactory information processing in insects revealed by real-time optical imaging of intrinsic signals.- Thermal Imaging of the Brain.- Infrared imaging of brain function.- IR thermal imaging of a monkey's head: Local temperature changes in response to somatosensory stimulation.- Optical Measurement of Ion Concentrations in Brain Cells and Tissues.- Spatiotemporal inhomogeneity of [Ca]i in neurons.- Intracellular ion concentrations in the brain: approaches towards in situ confocal imaging.- Optical Access to the Brain Microcirculation.- Optical access to the brain: how artificial are cranial window techniques?.- Multiparametric imaging of microregional circulation over the brain cortex by videoreflectometry.- Towards imaging of cerebral blood flow and metabolism on a microscopical scale in vivo.- Emerging Optical Techniques.- Detection of brain free oxygen radical generated photons in vivo: Preliminary results.- Diffusion properties of brain tissue measured with electrode methods and prospects for optical analysis.- Measuring oxygen using oxygen dependent quenching of phosphorescence: A status report.- Laser fluorescence spectroscopic experiments for monitoring molecules in brain.- Infrared-interference videomicroscopy of living brain slices.- Non-Optical Reference Techniques.- Blood-brain barrier transport measurements using PET-scanning and intravenous double indicator technique.- Nuclear magnetic resonance studies of human brain in vivo: Anatomy, function, and metabolism.- Autoradiographic and biochemical imaging in cerebral ischemia.- Contributors.