scholarly journals MRI Estimation of Global Brain Oxygen Consumption Rate

2010 ◽  
Vol 30 (9) ◽  
pp. 1598-1607 ◽  
Author(s):  
Varsha Jain ◽  
Michael C Langham ◽  
Felix W Wehrli
Keyword(s):  
Magnetic Resonance ◽  
Oxygen Saturation ◽  
Cerebral Metabolism ◽  
Temporal Variations ◽  
Acquisition Time ◽  
Blood Oxygen Saturation ◽  
Short Acquisition Time ◽  
Global Estimate ◽  
Sagittal Sinus

Measuring the global cerebral metabolic rate of oxygen ( CMRO2) is a valuable tool for assessing brain vitality and function. Measurement of blood oxygen saturation ( HbO2) and flow in the major cerebral outflow and inflow vessels can provide a global estimate of CMRO2. We demonstrate a rapid noninvasive method for quantifying CMRO2 by simultaneously measuring venous oxygen saturation in the superior sagittal sinus with magnetic resonance susceptometry-based oximetry, a technique that exploits the intrinsic susceptibility of deoxygenated hemoglobin, and the average blood inflow rate with phase-contrast magnetic resonance imaging. The average venous HbO2, cerebral blood flow, and global CMRO2 values in eight healthy, normal study subjects were 64%±4%, 45.2±3.2 mL per 100 g per minute, and 127±7 μmol per 100 g per minute, respectively. These values are in good agreement with those reported in literature. The technique described is noninvasive, robust, and reproducible for in vivo applications, making it ideal for use in clinical settings for assessing the pathologies associated with dysregulation of cerebral metabolism. In addition, the short acquisition time (∼30 seconds) makes the technique suitable for studying the temporal variations in CMRO2 in response to physiologic challenges.

In vivo measurement of blood oxygen saturation changes during motor activation using magnetic resonance imaging

NeuroImage ◽  
1996 ◽  
Vol 3 (3) ◽  
pp. S4 ◽  
Author(s):  
E.M. Haacke ◽  
S. Lai ◽  
J.R. Reichenbach ◽  
K. Kuppusamy ◽  
F.G.C. Hoogenraad ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Oxygen Saturation ◽  
Blood Oxygen ◽  
Resonance Imaging ◽  
Blood Oxygen Saturation ◽  
In Vivo Measurement ◽  
Motor Activation

scholarly journals Quantitative Measurements of Cerebral Blood Oxygen Saturation Using Magnetic Resonance Imaging

2000 ◽  
Vol 20 (8) ◽  
pp. 1225-1236 ◽  
Author(s):  
Hongyu An ◽  
Weili Lin
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Oxygen Saturation ◽  
Spin Echo ◽  
Oxygen Metabolism ◽  
Whole Body ◽  
Blood Oxygen ◽  
Resonance Imaging ◽  
Blood Oxygen Saturation

A quantitative estimate of cerebral blood oxygen saturation is of critical importance in the investigation of cerebrovascular disease because of the fact that it could potentially provide information on tissue viability in vivo. In the current study, a multi-echo gradient and spin echo magnetic resonance imaging sequence was used to acquire images from eight normal volunteer subjects. All images were acquired on a Siemens 1.5T Symphony whole-body scanner (Siemens, Erlangen, Germany). A theoretical signal model, which describes the signal dephasing phenomena in the presence of deoxyhemoglobin, was used for postprocessing of the acquired images and obtaining a quantitative measurement of cerebral blood oxygen saturation in vivo. With a region-of-interest analysis, a mean cerebral blood oxygen saturation of 58.4% ± 1.8% was obtained in the brain parenchyma from all volunteers. It is in excellent agreement with the known cerebral blood oxygen saturation under normal physiologic conditions in humans. Although further studies are needed to overcome some of the confounding factors affecting the estimates of cerebral blood oxygen saturation, these preliminary results are encouraging and should open a new avenue for the noninvasive investigation of cerebral oxygen metabolism under different pathophysiologic conditions using a magnetic resonance imaging approach.

scholarly journals Optical Measurement of Blood Oxygen Saturation of Dental Pulp

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Satoko Kakino ◽  
Shinya Kushibiki ◽  
Azusa Yamada ◽  
Zenzo Miwa ◽  
Yuzo Takagi ◽  
...  
Keyword(s):  
Light Intensity ◽  
Oxygen Saturation ◽  
Dental Pulp ◽  
Optical Measurement ◽  
Blood Oxygen ◽  
Arterial Pulse ◽  
Blood Oxygen Saturation ◽  
Visible Wavelengths

The applicability of arterial pulse oximetry to dental pulp was demonstrated using in vitro and in vivo measurements. First, porcine blood of known oxygen saturation (SO2) was circulated through extracted human upper incisors, while transmitted-light plethysmography was performed using three different visible wavelengths. From the light intensity waveforms measured in vitro, a parameter that is statistically correlated to SO2 was calculated using the pulsatile/nonpulsatile component ratios of two wavelengths for different SO2. Then, values were measured in vivo for living incisors, and the corresponding SO2 values were calculated using the results of in vitro measurements. The estimated SO2 values of the upper central incisors measured in vivo were from 71.0 to 92.7%. This study showed the potential to measure the oxygen saturation changes to identify the sign of pulpal inflammation.

scholarly journals Brain oxygen saturation assessment in neonates using T2-prepared blood imaging of oxygen saturation and near-infrared spectroscopy

2016 ◽  
Vol 37 (3) ◽  
pp. 902-913 ◽  
Author(s):  
Thomas Alderliesten ◽  
Jill B De Vis ◽  
Petra MA Lemmers ◽  
Jeroen Hendrikse ◽  
Floris Groenendaal ◽  
...  
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Infrared Spectroscopy ◽  
Magnetic Resonance ◽  
Oxygen Saturation ◽  
Near Infrared Spectroscopy ◽  
Near Infrared ◽  
Sagittal Sinus ◽  
Venous Oxygen Saturation ◽  
Blood Imaging

Although near-infrared spectroscopy is increasingly being used to monitor cerebral oxygenation in neonates, it has a limited penetration depth. The T2-prepared Blood Imaging of Oxygen Saturation (T2-BIOS) magnetic resonance sequence provides an oxygen saturation estimate on a voxel-by-voxel basis, without needing a respiratory calibration experiment. In 15 neonates, oxygen saturation measured by T2-prepared blood imaging of oxygen saturation and near-infrared spectroscopy were compared. In addition, these measures were compared to cerebral blood flow and venous oxygen saturation in the sagittal sinus. A strong linear relation was found between the oxygen saturation measured by magnetic resonance imaging and the oxygen saturation measured by near-infrared spectroscopy ( R2 = 0.64, p < 0.001). Strong linear correlations were found between near-infrared spectroscopy oxygen saturation, and magnetic resonance imaging measures of frontal cerebral blood flow, whole brain cerebral blood flow and venous oxygen saturation in the sagittal sinus ( R2 = 0.71, 0.50, 0.65; p < 0.01). The oxygen saturation obtained by T2-prepared blood imaging of oxygen saturation correlated with venous oxygen saturation in the sagittal sinus ( R2 = 0.49, p = 0.023), but no significant correlations could be demonstrated with frontal and whole brain cerebral blood flow. These results suggest that measuring oxygen saturation by T2-prepared blood imaging of oxygen saturation is feasible, even in neonates. Strong correlations between the various methods work as a cross validation for near-infrared spectroscopy and T2-prepared blood imaging of oxygen saturation, confirming the validity of using of these techniques for determining cerebral oxygenation.

scholarly journals Retinal Imaging of Infants on Spectral Domain Optical Coherence Tomography

2015 ◽  
Vol 2015 ◽  
pp. 1-12 ◽  
Author(s):  
Anand Vinekar ◽  
Shwetha Mangalesh ◽  
Chaitra Jayadev ◽  
Ramiro S. Maldonado ◽  
Noel Bauer ◽  
...  
Keyword(s):  
Spectral Domain ◽  
Current Status ◽  
Acquisition Time ◽  
Imaging Device ◽  
Short Acquisition Time ◽  
Visual Potential ◽  
Detailed Assessment ◽  
First Year Of Life ◽  
Sd Oct

Spectral domain coherence tomography (SD OCT) has become an important tool in the management of pediatric retinal diseases. It is a noncontact imaging device that provides detailed assessment of the microanatomy and pathology of the infant retina with a short acquisition time allowing office examination without the requirement of anesthesia. Our understanding of the development and maturation of the infant fovea has been enhanced by SD OCT allowing an in vivo assessment that correlates with histopathology. This has helped us understand the critical correlation of foveal development with visual potential in the first year of life and beyond. In this review, we summarize the recent literature on the clinical applications of SD OCT in studying the pathoanatomy of the infant macula, its ability to detect subclinical features, and its correlation with disease and vision. Retinopathy of prematurity and macular edema have been discussed in detail. The review also summarizes the current status of SD OCT in other infant retinal conditions, imaging the optic nerve, the choroid, and the retinal nerve fibre in infants and children, and suggests future areas of research.

In vivo 31P nuclear magnetic resonance (NMR) study of cerebral metabolism during histotoxic hypoxia in mice

1988 ◽  
Vol 3 (1) ◽  
pp. 37-48 ◽  
Author(s):  
Michel Peres ◽  
Philippe Meric ◽  
Bertrand Barrere ◽  
Corinne Pasquier ◽  
Guy Beranger ◽  
...  
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Cerebral Metabolism ◽  
31P Nuclear Magnetic Resonance ◽  
Nmr Study ◽  
Histotoxic Hypoxia ◽  
Nuclear Magnetic

scholarly journals Single Photon, Time-Gated, Phasor-based Fluorescence Lifetime Imaging Through Highly Scattering Medium

2019 ◽  
Author(s):  
Rinat Ankri ◽  
Arkaprabha Basu ◽  
Arin Can Ulku ◽  
Claudio Bruschini ◽  
Edoardo Charbon ◽  
...  
Keyword(s):  
Fluorescence Lifetime ◽  
Fluorescence Intensity ◽  
Single Photon ◽  
Acquisition Time ◽  
Fluorescence Signal ◽  
Wide Field ◽  
Fluorescence Lifetime Imaging ◽  
Short Acquisition Time ◽  
Lifetime Imaging

AbstractFluorescence lifetime imaging (FLI) is a powerful tool for in vitro and non-invasive in vivo biomolecular and cellular investigations. Fluorescence lifetime is an intrinsic characteristic of any fluorescent dye which, to some extent, does not depend on excitation intensity and signal level. However, when used in vivo with visible wavelength emitting fluorophores, FLI is complicated by (i) light scattering as well as absorption by tissues, which significantly reduces fluorescence intensity, (ii) tissue autofluorescence (AF), which decreases the signal to noise ratio and (iii) broadening of the decay signal, which can result in incorrect lifetime estimation. Here, we report the use of a large-frame time-gated single-photon avalanche diode (SPAD) imager, SwissSPAD2, with a very short acquisition time (in the milliseconds range) and a wide-field microscopy format. We use the phasor approach to convert each pixel’s data into its local lifetime. The phasor transformation provides a simple and fast visual method for lifetime imaging and is particularly suitable for in vivo FLI which suffers from deformation of the fluorescence decay, and makes lifetime extraction by standard fitting challenging. We show, for single dyes, that the phasor cloud distribution (of pixels) increases with decay broadening due to scattering and decreasing fluorescence intensity. Yet, as long as the fluorescence signal is higher than the tissue-like phantom AF, a distinct lifetime can still be clearly identified with an appropriate background correction. Lastly, we demonstrate the detection of few hundred thousand A459 cells expressing the fluorescent protein mCyRFP1 through highly scattering phantom layers, despite significant scattering and the presence of the phantom AF.

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