In-vivo monitoring of tissue oxygen saturation in deep brain structures using a single fiber optical system

Topical agents like nonivamide and nicoboxil induce hyperaemisation and increase cutaneous blood flow and temperature. This study aimed to determine the effects of a nonivamide–nicoboxil cream on haemodynamics in the skin and calf muscle, via optical spectroscopy, discriminating between the changes for skin and muscle. Optical spectroscopy was applied in the visible (VIS) and near-infrared (NIR) wavelength range. The study determined the effect of the cream on changes in oxygenated (ΔoxyHb) and deoxygenated (ΔdeoxyHb) haemoglobin in skin and muscle, as well as on tissue oxygen saturation (SO2) in the skin of 14 healthy subjects. The left and right calves of the subjects were either treated with nonivamide–nicoboxil cream or were sham-administered. NIR spectroscopy allows noninvasive in-vivo examination of the oxygenation of human skeletal muscle. Topical administration of the nonivamide–nicoboxil cream significantly increased the concentration of oxygenated haemoglobin and tissue oxygen saturation in the skin, as well as the concentration of oxygenated haemoglobin in the muscle of the treated legs after 15 min, but with stronger and faster effects in the skin. The topical application of the nonivamide–nicoboxil cream increased blood flow in (smaller vessels of) the skin and muscle tissues.

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In Vivo Assessment of Hypoxia Levels in Pancreatic Tumors Using a Dual-Modality Ultrasound/Photoacoustic Imaging System

Micromachines ◽

10.3390/mi12060668 ◽

2021 ◽

Vol 12 (6) ◽

pp. 668

Author(s):

Yuhling Wang ◽

De-Fu Jhang ◽

Chia-Hua Tsai ◽

Nai-Jung Chiang ◽

Chia-Hui Tsao ◽

...

Keyword(s):

Tumor Growth ◽

Oxygen Saturation ◽

Pancreatic Tumor ◽

Tissue Oxygenation ◽

Imaging System ◽

Tissue Oxygen Saturation ◽

Functional Information ◽

Tissue Oxygen ◽

Dual Modality

Noninvasive anatomical and functional imaging has become an essential tool to evaluate tissue oxygen saturation dynamics in preclinical or clinical studies of hypoxia. Our dual-wavelength technique for photoacoustic (PA) imaging based on the differential absorbance spectrum of oxyhemoglobin (oxy-Hb) and deoxyhemoglobin (deoxy-Hb) can quantify tissue oxygen saturation using the intrinsic contrast property. PA imaging of tissue oxygen saturation can be used to monitor tumor-related hypoxia, which is a particularly relevant functional parameter of the tumor microenvironment that has a strong influence on tumor aggressiveness. The simultaneous acquisition of anatomical and functional information using dual-modality ultrasound (US) and PA imaging technology enhances the preclinical applicability of the method. Here, the developed dual-modality US/PA system was used to measure relative tissue oxygenation using the dual-wavelength technique. Tissue oxygen saturation was quantified in a pancreatic tumor mouse model. The differences in tissue oxygenation were detected by comparing pancreatic samples from normal and tumor-bearing mice at various time points after implantation. The use of an in vivo pancreatic tumor model revealed changes in hypoxia at various stages of tumor growth. The US/PA imaging data positively correlated with the results of immunohistochemical staining for hypoxia. Thus, our dual-modality US/PA imaging system can be used to reliably assess and monitor hypoxia in pancreatic tumor mouse models. These findings enable the use of a combination of US and PA imaging to acquire anatomical and functional information on tumor growth and to evaluate treatment responses in longitudinal preclinical studies.

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Tissue Oxygen Saturation Mapping with Magnetic Resonance Imaging

Journal of Cerebral Blood Flow & Metabolism ◽

10.1038/jcbfm.2014.116 ◽

2014 ◽

Vol 34 (9) ◽

pp. 1550-1557 ◽

Cited By ~ 30

Author(s):

Thomas Christen ◽

Pierre Bouzat ◽

Nicolas Pannetier ◽

Nicolas Coquery ◽

Anaïck Moisan ◽

...

Keyword(s):

Magnetic Resonance Imaging ◽

Magnetic Resonance ◽

Oxygen Saturation ◽

Tissue Oxygen Saturation ◽

Blood Oxygen ◽

Oxygen Level ◽

Resonance Imaging ◽

Tissue Oxygen ◽

Invasive Approach

A quantitative estimate of cerebral blood oxygen saturation is of critical importance in the investigation of cerebrovascular disease. While positron emission tomography can map in vivo the oxygen level in blood, it has limited availability and requires ionizing radiation. Magnetic resonance imaging (MRI) offers an alternative through the blood oxygen level-dependent contrast. Here, we describe an in vivo and non-invasive approach to map brain tissue oxygen saturation ( StO2) with high spatial resolution. StO2 obtained with MRI correlated well with results from blood gas analyses for various oxygen and hematocrit challenges. In a stroke model, the hypoxic areas delineated in vivo by MRI spatially matched those observed ex vivo by pimonidazole staining. In a model of diffuse traumatic brain injury, MRI was able to detect even a reduction in StO2 that was too small to be detected by histology. In a F98 glioma model, MRI was able to map oxygenation heterogeneity. Thus, the MRI technique may improve our understanding of the pathophysiology of several brain diseases involving impaired oxygenation.

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Faculty Opinions recommendation of Changes in cerebral tissue oxygen saturation during anaesthetic-induced hypotension: an interpretation based on neurovascular coupling and cerebral autoregulation.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.718004161.793475754 ◽

2013 ◽

Author(s):

Luzius A Steiner

Keyword(s):

Oxygen Saturation ◽

Cerebral Autoregulation ◽

Neurovascular Coupling ◽

Tissue Oxygen Saturation ◽

Tissue Oxygen ◽

Cerebral Tissue ◽

Induced Hypotension ◽

Cerebral Tissue Oxygen Saturation

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Quantifying dermal microcirculatory changes of neuropathic and neuroischemic diabetic foot ulcers using spatial frequency domain imaging: a shade of things to come?

BMJ Open Diabetes Research & Care ◽

10.1136/bmjdrc-2020-001815 ◽

2020 ◽

Vol 8 (2) ◽

pp. e001815

Author(s):

Grant A Murphy ◽

Rajinder P Singh-Moon ◽

Amaan Mazhar ◽

David J Cuccia ◽

Vincent L Rowe ◽

...

Keyword(s):

Diabetes Mellitus ◽

Spatial Frequency ◽

Oxygen Saturation ◽

Diabetic Foot ◽

Clinical Course ◽

Tissue Oxygen Saturation ◽

Tissue Oxygen ◽

Spatial Frequency Domain Imaging ◽

Patients With Diabetes ◽

Spatial Frequency Domain

IntroductionThe use of non-invasive vascular and perfusion diagnostics are an important part of assessing lower extremity ulceration and amputation risk in patients with diabetes mellitus. Methods for detecting impaired microvascular vasodilatory function in patients with diabetes may have the potential to identify sites at risk of ulceration prior to clinically identifiable signs. Spatial frequency domain imaging (SFDI) uses patterned near-infrared and visible light spectroscopy to determine tissue oxygen saturation and hemoglobin distribution within the superficial and deep dermis, showing distinct microcirculatory and oxygenation changes that occur prior to neuropathic and neuroischemic ulceration.Research designs and methods35 patients with diabetes mellitus and a history of diabetic foot ulceration were recruited for monthly imaging with SFDI. Two patients who ulcerated during the year-long longitudinal study were selected for presentation of their clinical course alongside the dermal microcirculation biomarkers from SFDI.ResultsPatient 1 developed a neuropathic ulcer portended by a focal increase in tissue oxygen saturation and decrease in superficial papillary hemoglobin concentration 3 months prior. Patient 2 developed bilateral neuroischemic ulcers showing decreased tissue oxygen saturation and increased superficial papillary and deep dermal reticular hemoglobin concentrations.ConclusionsWounds of different etiology show unique dermal microcirculatory changes prior to gross ulceration. Before predictive models can be developed from SFDI, biomarker data must be correlated with the clinical course of patients who ulcerate while being followed longitudinally.Trial registration numberNCT03341559.

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