Diffuse optical correlation tomography of cerebral blood flow during cortical spreading depression in rat brain.

Optics Express (Impact Factor: 3.53). 03/2006; 14(3):1125-44. DOI: 10.1364/OE.14.001125
Source: PubMed

ABSTRACT Diffuse optical correlation methods were adapted for three-dimensional (3D) tomography of cerebral blood flow (CBF) in small animal models. The image reconstruction was optimized using a noise model for diffuse correlation tomography which enabled better data selection and regularization. The tomographic approach was demonstrated with simulated data and during in-vivo cortical spreading depression (CSD) in rat brain. Three-dimensional images of CBF were obtained through intact skull in tissues(~4mm) deep below the cortex.


Available from: Joel H Greenberg, Dec 17, 2013
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    ABSTRACT: Diffuse correlation spectroscopy (DCS) is an emerging optical modality used to measure cortical cerebral blood flow. This outlook presents a brief overview of the technology, summarizing the advantages and limitations of the method, and describing its recent applications to animal, adult, and infant cohorts. At last, the paper highlights future applications where DCS may play a pivotal role individualizing patient management and enhancing our understanding of neurovascular coupling, activation, and brain development.
    06/2014; 1(1). DOI:10.1117/1.NPh.1.1.011009
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    ABSTRACT: Noninvasive measurement of hemodynamics at the microvascular level may have a great impact on oncology in clinics for diagnosis, therapy planning and monitoring, and, in preclinical studies. To this end, diffuse optics is a strong candidate for noninvasive, repeated, deep tissue monitoring. In this multi-disciplinary, translational work, I have constructed and deployed hybrid devices which are the combination of two qualitatively different methods, near infrared diffuse optical spectroscopy (NIRS) and diffuse correlation spectroscopy (DCS), for simultaneous measurement of microvascular total hemoglobin concentration, blood oxygen saturation and blood flow. In a preclinical study, I applied the hybrid device to monitor the response of renal cell carcinoma in mice to antiangiogenic therapy. The results suggest that we can predict the output of therapy from early hemodynamic changes, which provide us with valuable information for better understanding of the tumor resistance mechanism to antiangiogenic therapies. In two in vivo studies in human volunteers, I have developed protocols and probes to demonstrate the feasibility of noninvasive diffuse optical spectroscopy to investigate the pathophysiology of bone. First study was study on the physiology of the patella microvasculature, the other introduced the manubrium as a site that is rich in red bone mar- row and accessible to diffuse optics as a potential window to monitor the progression of hematological malignancies. Overall, during my Ph.D., I have developed instrumentation, algorithms and protocols and, then, applied this technique for preclinical and clinical investigations. My research is a link between preclinical and clinical studies and it opens new areas of applications in oncology.
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    ABSTRACT: Diffuse reflectance spectroscopy using fiber optic probe is one of most promising technique for evaluating optical properties of biological tissue. We present a method determining the reduced scattering coefficients μs’, the absorption coefficients μa, and tissue oxygen saturation StO2 of in vivo brain tissue using single reflectance fiber probe with two source-collector geometries. In this study, we performed in vivo recordings of diffuse reflectance spectra and the electrophysiological signals for exposed brain of rats during the cortical spreading depression (CSD) evoked by the topical application of KCl. The time courses of μa in the range from 500 to 584 nm and StO2 indicated the hemodynamic change in cerebral cortex. Time courses of μs’ are well correlated with those of μa in the range from 530 to 570 nm, which also reflect the scattering by red blood cells. On the other hand, increases in μs’ at 500 and 584 nm were observed before the profound increase in μa and they synchronized with the negative DC shift of the local field potential. It is said that the DC shift coincident with a rise in extracellular potassium and can evoke cell deformation generated by water movement between intracellular and extracellular compartments, and hence the light scattering by tissue. Therefore, the increase in μs’ at 500 and 584 nm before the profound increase in μa are indicative of changes in light scattering by tissue. The results in this study indicate potential of the method to evaluate the pathophysiological conditions of in vivo brain.
    Conference on Optical Tomography and Spectroscopy of Tissue X; 03/2013