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Huang J, Chen Z, van Zijl PCM, Law LH, Pemmasani Prabakaran RS, Park SW, Xu J, Chan KWY. Effect of inhaled oxygen level on dynamic glucose-enhanced MRI in mouse brain. Magn Reson Med 2024; 92:57-68. [PMID: 38308151 PMCID: PMC11055662 DOI: 10.1002/mrm.30035] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2023] [Revised: 12/23/2023] [Accepted: 01/15/2024] [Indexed: 02/04/2024]
Abstract
PURPOSE To investigate the effect of inhaled oxygen level on dynamic glucose enhanced (DGE) MRI in mouse brain tissue and CSF at 3 T. METHODS DGE data of brain tissue and CSF from mice under normoxia or hyperoxia were acquired in independent and interleaved experiments using on-resonance variable delay multi-pulse (onVDMP) MRI. A bolus of 0.15 mL filtered 50% D-glucose was injected through the tail vein over 1 min during DGE acquisition. MRS was acquired before and after DGE experiments to confirm the presence of D-glucose. RESULTS A significantly higher DGE effect under normoxia than under hyperoxia was observed in brain tissue (p = 0.0001 and p = 0.0002 for independent and interleaved experiments, respectively), but not in CSF (p > 0.3). This difference is attributed to the increased baseline MR tissue signal under hyperoxia induced by a shortened T1 and an increased BOLD effect. When switching from hyperoxia to normoxia without glucose injection, a signal change of ˜3.0% was found in brain tissue and a signal change of ˜1.5% was found in CSF. CONCLUSIONS DGE signal was significantly lower under hyperoxia than that under normoxia in brain tissue, but not in CSF. The reason is that DGE effect size of brain tissue is affected by the baseline signal, which could be influenced by T1 change and BOLD effect. Therefore, DGE experiments in which the oxygenation level is changed from baseline need to be interpreted carefully.
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Affiliation(s)
- Jianpan Huang
- Department of Diagnostic Radiology, The University of Hong Kong, Hong Kong, China
| | - Zilin Chen
- Department of Biomedical Engineering, City University of Hong Kong, Hong Kong, China
| | - Peter CM van Zijl
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Research Institute, Baltimore, MD, USA
- Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Lok Hin Law
- Department of Biomedical Engineering, City University of Hong Kong, Hong Kong, China
| | - Rohith Saai Pemmasani Prabakaran
- Department of Biomedical Engineering, City University of Hong Kong, Hong Kong, China
- Hong Kong Centre for Cerebro-Cardiovascular Health Engineering (COCHE), Hong Kong, China
| | - Se Weon Park
- Department of Biomedical Engineering, City University of Hong Kong, Hong Kong, China
- Hong Kong Centre for Cerebro-Cardiovascular Health Engineering (COCHE), Hong Kong, China
| | - Jiadi Xu
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Research Institute, Baltimore, MD, USA
- Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Kannie WY Chan
- Department of Biomedical Engineering, City University of Hong Kong, Hong Kong, China
- Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Hong Kong Centre for Cerebro-Cardiovascular Health Engineering (COCHE), Hong Kong, China
- City University of Hong Kong Shenzhen Research Institute, Shenzhen, China
- Tung Biomedical Science Centre, City University of Hong Kong, Hong Kong, China
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Bluemke E, Young LAJ, Owen J, Smart S, Kinchesh P, Bulte DP, Stride E. Determination of oxygen relaxivity in oxygen nanobubbles at 3 and 7 Tesla. MAGMA (NEW YORK, N.Y.) 2022; 35:817-826. [PMID: 35416627 PMCID: PMC9463275 DOI: 10.1007/s10334-022-01009-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/05/2021] [Revised: 03/15/2022] [Accepted: 03/18/2022] [Indexed: 12/15/2022]
Abstract
OBJECTIVE Oxygen-loaded nanobubbles have shown potential for reducing tumour hypoxia and improving treatment outcomes, however, it remains difficult to noninvasively measure the changes in partial pressure of oxygen (PO2) in vivo. The linear relationship between PO2 and longitudinal relaxation rate (R1) has been used to noninvasively infer PO2 in vitreous and cerebrospinal fluid, and therefore, this experiment aimed to investigate whether R1 is a suitable measurement to study oxygen delivery from such oxygen carriers. METHODS T1 mapping was used to measure R1 in phantoms containing nanobubbles with varied PO2 to measure the relaxivity of oxygen (r1Ox) in the phantoms at 7 and 3 T. These measurements were used to estimate the limit of detection (LOD) in two experimental settings: preclinical 7 T and clinical 3 T MRI. RESULTS The r1Ox in the nanobubble solution was 0.00057 and 0.000235 s-1/mmHg, corresponding to a LOD of 111 and 103 mmHg with 95% confidence at 7 and 3 T, respectively. CONCLUSION This suggests that T1 mapping could provide a noninvasive method of measuring a > 100 mmHg oxygen delivery from therapeutic nanobubbles.
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Affiliation(s)
- Emma Bluemke
- Department of Engineering Sciences, Institute of Biomedical Engineering, University of Oxford, Oxford, UK.
| | - Liam A J Young
- Radcliffe Department of Medicine, Oxford Centre for Clinical Magnetic Resonance Research, University of Oxford, Oxford, UK
| | - Joshua Owen
- Clinical Center, National Institutes of Health, Bethesda, MD, USA
| | - Sean Smart
- Department of Oncology, Radiobiology Research Institute, University of Oxford, Oxford, UK
| | - Paul Kinchesh
- Department of Oncology, Radiobiology Research Institute, University of Oxford, Oxford, UK
| | - Daniel P Bulte
- Department of Engineering Sciences, Institute of Biomedical Engineering, University of Oxford, Oxford, UK
| | - Eleanor Stride
- Department of Engineering Sciences, Institute of Biomedical Engineering, University of Oxford, Oxford, UK
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Bluemke E, Stride E, Bulte DP. A General Model to Calculate the Spin-Lattice Relaxation Rate (R1) of Blood, Accounting for Hematocrit, Oxygen Saturation, Oxygen Partial Pressure, and Magnetic Field Strength Under Hyperoxic Conditions. J Magn Reson Imaging 2022; 55:1428-1439. [PMID: 34596290 DOI: 10.1002/jmri.27938] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2021] [Revised: 09/16/2021] [Accepted: 09/18/2021] [Indexed: 01/02/2023] Open
Abstract
BACKGROUND Under normal physiological conditions, the spin-lattice relaxation rate (R1) in blood is influenced by many factors, including hematocrit, field strength, and the paramagnetic effects of deoxyhemoglobin and dissolved oxygen. In addition, techniques such as oxygen-enhanced magnetic resonance imaging (MRI) require high fractions of inspired oxygen to induce hyperoxia, which complicates the R1 signal further. A quantitative model relating total blood oxygen content to R1 could help explain these effects. PURPOSE To propose and assess a general model to estimate the R1 of blood, accounting for hematocrit, SO2 , PO2 , and B0 under both normal physiological and hyperoxic conditions. STUDY TYPE Mathematical modeling. POPULATION One hundred and twenty-six published values of R1 from phantoms and animal models. FIELD STRENGTH/SEQUENCE 5-8.45 T. ASSESSMENT We propose a two-compartment nonlinear model to calculate R1 as a function of hematocrit, PO2 , and B0. The Akaike Information Criterion (AIC) was used to select the best-performing model with the fewest parameters. A previous model of R1 as a function of hematocrit, SO2 , and B0 has been proposed by Hales et al, and our work builds upon this work to make the model applicable under hyperoxic conditions (SO2 > 0.99). Models were assessed using the AIC, mean squared error (MSE), coefficient of determination (R2 ), and Bland-Altman analysis. The effect of volume fraction constants W RBC and W plasma was assessed by the SD of resulting R1. The range of the model was determined by the maximum and minimum B0, hematocrit, SO2 , and PO2 of the literature data points. STATISTICAL TESTS Bland-Altman, AIC, MSE, coefficient of determination (R2 ), SD. RESULTS The model estimates agreed well with the literature values of R1 of blood (R2 = 0.93, MSE = 0.0013 s-2 ), and its performance was consistent across the range of parameters: B0 = 1.5-8.45 T, SO2 = 0.40-1, PO2 = 30-700 mmHg. DATA CONCLUSION Using the results from this model, we have quantified and explained the contradictory decrease in R1 reported in oxygen-enhanced MRI and oxygen-delivery experiments. LEVEL OF EVIDENCE 3 TECHNICAL EFFICACY: Stage 1.
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Affiliation(s)
- Emma Bluemke
- Department of Engineering Sciences, Institute of Biomedical Engineering, University of Oxford, Oxford, UK
| | - Eleanor Stride
- Department of Engineering Sciences, Institute of Biomedical Engineering, University of Oxford, Oxford, UK
| | - Daniel P Bulte
- Department of Engineering Sciences, Institute of Biomedical Engineering, University of Oxford, Oxford, UK
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Using Variable Flip Angle (VFA) and Modified Look-Locker Inversion Recovery (MOLLI) T1 mapping in clinical OE-MRI. Magn Reson Imaging 2022; 89:92-99. [PMID: 35341905 DOI: 10.1016/j.mri.2022.03.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2021] [Revised: 03/16/2022] [Accepted: 03/19/2022] [Indexed: 11/20/2022]
Abstract
BACKGROUND AND PURPOSE The imaging technique known as Oxygen-Enhanced MRI is under development as a noninvasive technique for imaging hypoxia in tumours and pulmonary diseases. While promising results have been shown in preclinical experiments, clinical studies have mentioned experiencing difficulties with patient motion, image registration, and the limitations of single-slice images compared to 3D volumes. As clinical studies begin to assess feasibility of using OE-MRI in patients, it is important for researchers to communicate about the practical challenges experienced when using OE-MRI on patients to help the technique advance. MATERIALS AND METHODS We report on our experience with using two types of T1 mapping (MOLLI and VFA) for a recently completed OE-MRI clinical study on oropharyngeal squamous cell carcinoma. RESULTS We report: (1) the artefacts and practical difficulties encountered in this study; (2) the difference in estimated T1 from each method used - the VFA T1 estimation was higher than the MOLLI estimation by 27% on average; (3) the standard deviation within the tumour ROIs - there was no significant difference in the standard deviation seen within the tumour ROIs from the VFA versus MOLLI; and (4) the OE-MRI response collected from either method. Lastly, we collated the MRI acquisition details from over 45 relevant manuscripts as a convenient reference for researchers planning future studies. CONCLUSION We have reported our practical experience from an OE-MRI clinical study, with the aim that sharing this is helpful to researchers planning future studies. In this study, VFA was a more useful technique for using OE-MRI in tumours than MOLLI T1 mapping.
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Bluemke E, Bulte D, Bertrand A, George B, Cooke R, Chu KY, Durrant L, Goh V, Jacobs C, Ng SM, Strauss VY, Hawkins MA, Muirhead R. Oxygen-enhanced MRI MOLLI T1 mapping during chemoradiotherapy in anal squamous cell carcinoma. Clin Transl Radiat Oncol 2020; 22:44-49. [PMID: 32211520 PMCID: PMC7082428 DOI: 10.1016/j.ctro.2020.03.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2020] [Accepted: 03/01/2020] [Indexed: 11/01/2022] Open
Abstract
BACKGROUND AND PURPOSE Oxygen-enhanced magnetic resonance imaging (MRI) and T1-mapping was used to explore its effectiveness as a prognostic imaging biomarker for chemoradiotherapy outcome in anal squamous cell carcinoma. MATERIALS AND METHODS T2-weighted, T1 mapping, and oxygen-enhanced T1 maps were acquired before and after 8-10 fractions of chemoradiotherapy and examined whether the oxygen-enhanced MRI response relates to clinical outcome. Patient response to treatment was assessed 3 months following completion of chemoradiotherapy. A mean T1 was extracted from manually segmented tumour regions of interest and a paired two-tailed t-test was used to compare changes across the patient population. Regions of subcutaneous fat and muscle tissue were examined as control ROIs. RESULTS There was a significant increase in T1 of the tumour ROIs across patients following the 8-10 fractions of chemoradiotherapy (paired t-test, p < 0.001, n = 7). At baseline, prior to receiving chemoradiotherapy, there were no significant changes in T1 across patients from breathing oxygen (n = 9). In the post-chemoRT scans (8-10 fractions), there was a significant decrease in T1 of the tumour ROIs across patients when breathing 100% oxygen (paired t-test, p < 0.001, n = 8). Out of the 12 patients from which we successfully acquired a visit 1 T1-map, only 1 patient did not respond to treatment, therefore, we cannot correlate these results with clinical outcome. CONCLUSIONS These clinical data demonstrate feasibility and potential for T1-mapping and oxygen enhanced T1-mapping to indicate perfusion or treatment response in tumours of this nature. These data show promise for future work with a larger cohort containing more non-responders, which would allow us to relate these measurements to clinical outcome.
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Affiliation(s)
- Emma Bluemke
- Institute of Biomedical Engineering, University of Oxford, UK
| | - Daniel Bulte
- Institute of Biomedical Engineering, University of Oxford, UK
| | - Ambre Bertrand
- Institute of Biomedical Engineering, University of Oxford, UK
| | - Ben George
- Institute of Biomedical Engineering, University of Oxford, UK
| | - Rosie Cooke
- Radiotherapy Department, Oxford University Hospitals NHS Foundation Trust, UK
- Department of Oncology, CRUK/MRC Oxford Institute for Radiation Oncology, University of Oxford, UK
| | - Kwun-Ye Chu
- Radiotherapy Department, Oxford University Hospitals NHS Foundation Trust, UK
- Department of Oncology, CRUK/MRC Oxford Institute for Radiation Oncology, University of Oxford, UK
| | - Lisa Durrant
- Department of Oncology, CRUK/MRC Oxford Institute for Radiation Oncology, University of Oxford, UK
| | - Vicky Goh
- Department of Oncology, CRUK/MRC Oxford Institute for Radiation Oncology, University of Oxford, UK
| | - Clare Jacobs
- Department of Oncology, Oxford University Hospitals NHS Foundation Trust, UK
| | - Stasya M. Ng
- Department of Oncology, CRUK/MRC Oxford Institute for Radiation Oncology, University of Oxford, UK
| | | | | | - Rebecca Muirhead
- Department of Oncology, Oxford University Hospitals NHS Foundation Trust, UK
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The Continuing Evolution of Molecular Functional Imaging in Clinical Oncology: The Road to Precision Medicine and Radiogenomics (Part II). Mol Diagn Ther 2019; 23:27-51. [PMID: 30387041 DOI: 10.1007/s40291-018-0367-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
The present era of precision medicine sees "cancer" as a consequence of molecular derangements occurring at the commencement of the disease process, with morphological changes happening much later in the process of tumourigenesis. Conventional imaging techniques, such as computed tomography (CT), ultrasound (US) and magnetic resonance imaging (MRI) play an integral role in the detection of disease at the macroscopic level. However, molecular functional imaging (MFI) techniques entail the visualisation and quantification of biochemical and physiological processes occurring during tumourigenesis. MFI has the potential to play a key role in heralding the transition from the concept of "one-size-fits-all" treatment to "precision medicine". Integration of MFI with other fields of tumour biology such as genomics has spawned a novel concept called "radiogenomics", which could serve as an indispensable tool in translational cancer research. With recent advances in medical image processing, such as texture analysis, deep learning and artificial intelligence, the future seems promising; however, their clinical utility remains unproven at present. Despite the emergence of novel imaging biomarkers, the majority of these require validation before clinical translation is possible. In this two part review, we discuss the systematic collaboration across structural, anatomical and molecular imaging techniques that constitute MFI. Part I reviews positron emission tomography, radiogenomics, AI, and optical imaging, while part II reviews MRI, CT and ultrasound, their current status, and recent advances in the field of precision oncology.
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Ożóg Ł, Domka W, Truszkiewicz A, Tarbarkiewicz J, Aebisher D. Monitoring photodynamic oxygen consumption by endogenous oxygen contrast MRI. Photodiagnosis Photodyn Ther 2019; 25:492-498. [PMID: 30738846 DOI: 10.1016/j.pdpdt.2019.02.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2018] [Revised: 01/20/2019] [Accepted: 02/04/2019] [Indexed: 12/19/2022]
Abstract
Photodynamic oxygen consumption was measured by changes in spin-lattice relaxation time (T1) in aqueous solution in a clinical GE scanner at 1.5 T. Similar measurements were attempted in excised laryngeal and thyroid tissues that were infused with Rose Bengal. First, T1 was measured as a function of dissolved oxygen in argon and in oxygen pre-saturated water samples that were opened to the atmosphere in a series of steps allowing air to diffuse into or out of solution; for both argon and oxygen saturated water solutions, stepwise air re-equilibration resulted in a return to air-saturated water T1. Secondly, T1 was measured as a function of time under type II photooxidative conditions in aqueous solution. Under type II photooxidative conditions, a 492 ± 53 ms increase in T1 was measured following 300 s of visible light illumination of aqueous solutions containing the photosensitizer Rose Bengal (2.5 × 10-6 M) and the singlet oxygen trap methionine (0.0012 M). The 492 ± 53 ms increase in T1 corresponded to consumption of all the measurable dissolved oxygen (˜ 0.1 mg O2 in 15.0 mL of H2O) during photooxidation of methionine in air saturated water. This rapid oxygen consumption, indicated by an increase in T1, is due to irreversible trapping of photogenerated singlet oxygen by methionine. Thirdly, an increase in T1 was observed in Rose Bengal infused normal laryngeal tissue, and in normal and cancerous thyroid tissue samples following 20 min of exposure to visible light. An increase in T1 was not observed after 40 min of illumination which suggests that the increases in T1 observed after 20 min were not due to water uptake, but rather to photoconsumption of interstitial dissolved oxygen.
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Affiliation(s)
- Łukasz Ożóg
- Center for Innovative Research in Medical and Natural Sciences, University of Rzeszów, Warzywna 1A, 35-959, Rzeszów, Poland
| | - Wojciech Domka
- Department of Otorhinolaryngology, Frederic Chopin Clinical Hospital No 1 in Rzeszów, Chopin 1, 35-057, Rzeszów, Poland
| | - Adrian Truszkiewicz
- Institute of Nursing and Health Sciences, Faculty of Medicine, University of Rzeszów, Aleja Rejtana 16A, 35-310, Rzeszów, Poland
| | - Jacek Tarbarkiewicz
- Center for Innovative Research in Medical and Natural Sciences, University of Rzeszów, Warzywna 1A, 35-959, Rzeszów, Poland; Department of Human Immunology, Faculty of Medicine, University of Rzeszów, Aleja Rejtana 16A, 35-310, Rzeszów, Poland
| | - David Aebisher
- Department of Photomedicine and Physical Chemistry, Faculty of Medicine, University of Rzeszów, Aleja Rejtana 16A, 35-310, Rzeszów, Poland.
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Clinical and Pre-clinical Methods for Quantifying Tumor Hypoxia. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1136:19-41. [PMID: 31201714 DOI: 10.1007/978-3-030-12734-3_2] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Hypoxia, a prevalent characteristic of most solid malignant tumors, contributes to diminished therapeutic responses and more aggressive phenotypes. The term hypoxia has two definitions. One definition would be a physiologic state where the oxygen partial pressure is below the normal physiologic range. For most normal tissues, the normal physiologic range is between 10 and 20 mmHg. Hypoxic regions develop when there is an imbalance between oxygen supply and demand. The impact of hypoxia on cancer therapeutics is significant: hypoxic tissue is 3× less radiosensitive than normoxic tissue, the impaired blood flow found in hypoxic tumor regions influences chemotherapy delivery, and the immune system is dependent on oxygen for functionality. Despite the clinical implications of hypoxia, there is not a universal, ideal method for quantifying hypoxia, particularly cycling hypoxia because of its complexity and heterogeneity across tumor types and individuals. Most standard imaging techniques can be modified and applied to measuring hypoxia and quantifying its effects; however, the benefits and challenges of each imaging modality makes imaging hypoxia case-dependent. In this chapter, a comprehensive overview of the preclinical and clinical methods for quantifying hypoxia is presented along with the advantages and disadvantages of each.
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Suh JY, Cho G, Song Y, Woo DC, Choi YS, Ryu EK, Park BW, Shim WH, Kim YR, Kim JK. Hyperoxia-Induced ΔR 1. Stroke 2018; 49:3012-3019. [PMID: 30571431 DOI: 10.1161/strokeaha.118.021469] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Background and Purpose- Acceleration of longitudinal relaxation under hyperoxic challenge (ie, hyperoxia-induced ΔR1) indicates oxygen accumulation and reflects baseline tissue oxygenation. We evaluated the feasibility of hyperoxia-induced ΔR1 for evaluating cerebral oxygenation status and degree of ischemic damage in stroke. Methods- In 24-hour transient stroke rat models (n=13), hyperoxia-induced ΔR1, ischemic severity (apparent diffusion coefficient [ADC]), vasogenic edema (R2), total and microvascular blood volume (superparamagnetic iron oxide-driven ΔR2* and ΔR2, respectively), and glucose metabolism activity (18F-fluorodeoxyglucose uptake on positron emission tomography) were measured. The distribution of these parameters according to hyperoxia-induced ΔR1 was analyzed. The partial pressure of tissue oxygen change during hyperoxic challenge was measured using fiberoptic tissue oximetry. In 4-hour stroke models (n=6), ADC and hyperoxia-induced ΔR1 was analyzed with 2,3,5-triphenyltetrazolium chloride staining being a criterion of infarction. Results- Ischemic hemisphere showed significantly higher hyperoxia-induced ΔR1 than nonischemic brain in a pattern depending on ADC. During hyperoxic challenge, ischemic hemisphere demonstrated uncontrolled increase of partial pressure of tissue oxygen, whereas contralateral hemisphere rapidly plateaued. Ischemic hemisphere also demonstrated significant correlation between hyperoxia-induced ΔR1 and R2. Hyperoxia-induced ΔR1 showed a significant negative correlation with 18F-fluorodeoxyglucose uptake. The ADC, R2, ΔR2, and 18F-fluorodeoxyglucose uptake showed a dichotomized distribution according to the hyperoxia-induced ΔR1 as their slopes and values were higher at low hyperoxia-induced ΔR1 (<50 ms-1) than at high ΔR1. In 4-hour stroke rats, the distribution of ADC according to the hyperoxia-induced ΔR1 was similar with 24-hour stroke rats. The hyperoxia-induced ΔR1 was greater in the infarct area (47±10 ms-1) than in peri-infarct area (16±4 ms-1; P<0.01). Conclusions- Hyperoxia-induced ΔR1 adequately indicates cerebral oxygenation and can be a feasible biomarker to classify the degree of ischemia-induced damage in neurovascular function and metabolism in stroke brain.
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Affiliation(s)
- Ji-Yeon Suh
- From the Department of Radiology, Research Institute of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, South Korea (J.-Y.S., D.-C.W., B.W.P., W.H.S., J.K.K.).,Bioimaging Research Team, Korea Basic Science Institute, Ochang Cheongwon, Chungbuk, Korea (J.-Y.S., G.C., Y.S., E.K.R.)
| | - Gyunggoo Cho
- Bioimaging Research Team, Korea Basic Science Institute, Ochang Cheongwon, Chungbuk, Korea (J.-Y.S., G.C., Y.S., E.K.R.)
| | - Youngkyu Song
- Bioimaging Research Team, Korea Basic Science Institute, Ochang Cheongwon, Chungbuk, Korea (J.-Y.S., G.C., Y.S., E.K.R.)
| | - Dong-Cheol Woo
- From the Department of Radiology, Research Institute of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, South Korea (J.-Y.S., D.-C.W., B.W.P., W.H.S., J.K.K.)
| | - Yoon Seok Choi
- Medical Research Institute, Gangneung Asan Hospital, Gangwon-do, South Korea (Y.S.C.)
| | - Eun Kyung Ryu
- Bioimaging Research Team, Korea Basic Science Institute, Ochang Cheongwon, Chungbuk, Korea (J.-Y.S., G.C., Y.S., E.K.R.)
| | - Bum Woo Park
- From the Department of Radiology, Research Institute of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, South Korea (J.-Y.S., D.-C.W., B.W.P., W.H.S., J.K.K.)
| | - Woo Hyun Shim
- From the Department of Radiology, Research Institute of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, South Korea (J.-Y.S., D.-C.W., B.W.P., W.H.S., J.K.K.)
| | - Young Ro Kim
- Department of Radiology, Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown (Y.R.K.)
| | - Jeong Kon Kim
- From the Department of Radiology, Research Institute of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, South Korea (J.-Y.S., D.-C.W., B.W.P., W.H.S., J.K.K.)
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Berkowitz BA, Lewin AS, Biswal MR, Bredell BX, Davis C, Roberts R. MRI of Retinal Free Radical Production With Laminar Resolution In Vivo. Invest Ophthalmol Vis Sci 2016; 57:577-85. [PMID: 26886890 PMCID: PMC4771178 DOI: 10.1167/iovs.15-18972] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose Recent studies have suggested the hypothesis that quench-assisted 1/T1 magnetic resonance imaging (MRI) measures free radical production with laminar resolution in vivo without the need of a contrast agent. Here, we test this hypothesis further by examining the spatial and detection sensitivity of quench-assisted 1/T1 MRI to strain, age, or retinal cell layer-specific genetic manipulations. Methods We studied: adult wild-type mice; mice at postnatal day 7 (P7); cre dependent retinal pigment epithelium (RPE)-specific MnSOD knockout mice; doxycycline-treated Sod2flox/flox mice lacking the cre transgene; and α-transducin knockout (Gnat1−/−) mice on a C57Bl/6 background. Transretinal 1/T1 profiles were mapped in vivo in the dark without or with antioxidant treatment, or followed by light exposure. We calibrated profiles spatially using optical coherence tomography. Results Dark-adapted RPE-specific MnSOD knockout mice had greater than normal 1/T1 in the RPE and outer nuclear layers that was corrected to wild-type levels by antioxidant treatment. Dark and light Gnat1−/− mice also had greater than normal outer retinal 1/T1 values. In adult wild-type mice, dark values of 1/T1 in the ellipsoid region and in the outer segment were suppressed by 13 minutes of light. By 29 minutes of light, 1/T1 reduction extended to the outer nuclear layer. Gnat1−/− mice demonstrated a faster light-evoked suppression of 1/T1 values in the outer retina. In P7 mice, transretinal 1/T1 profiles were the same in dark and light. Conclusions Quench-assisted MRI has the laminar resolution and detection sensitivity to evaluate normal and pathologic production of free radicals in vivo.
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Affiliation(s)
- Bruce A Berkowitz
- Department of Anatomy and Cell Biology Wayne State University School of Medicine, Detroit, Michigan, United States 2Department of Ophthalmology, Wayne State University School of Medicine, Detroit, Michigan, United States
| | - Alfred S Lewin
- Department of Molecular Genetics and Microbiology, University of Florida, Gainesville, Florida, United States
| | - Manas R Biswal
- Department of Molecular Genetics and Microbiology, University of Florida, Gainesville, Florida, United States
| | - Bryce X Bredell
- Department of Anatomy and Cell Biology Wayne State University School of Medicine, Detroit, Michigan, United States
| | - Christopher Davis
- Department of Anatomy and Cell Biology Wayne State University School of Medicine, Detroit, Michigan, United States
| | - Robin Roberts
- Department of Anatomy and Cell Biology Wayne State University School of Medicine, Detroit, Michigan, United States
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Berkowitz BA, Bredell BX, Davis C, Samardzija M, Grimm C, Roberts R. Measuring In Vivo Free Radical Production by the Outer Retina. Invest Ophthalmol Vis Sci 2016; 56:7931-8. [PMID: 26670830 DOI: 10.1167/iovs.15-18420] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
PURPOSE Excessive and continuously produced free radicals in the outer retina are implicated in retinal aging and the pathogenesis of sight-threatening retinopathies, yet measuring outer retinal oxidative stress in vivo remains a challenge. Here, we test the hypothesis that continuously produced paramagnetic free radicals from the outer retina can be measured in vivo using high-resolution (22-μm axial resolution) 1/T1magnetic resonance imaging (MRI) without and with a confirmatory quench (quench-assisted MRI). METHODS Low-dose sodium iodate-treated and diabetic C57Bl6/J mice (and their controls), and rod-dominated (129S6) or cone-only R91W;Nrl-/- mice were studied. In dark-adapted groups, 1/T1 was mapped transretinally in vivo without or with (1) the antioxidant combination of methylene blue (MB) and α-lipoic acid (LPA), or (2) light exposure; in subgroups, retinal superoxide production was measured ex vivo (lucigenin). RESULTS In the sodium iodate model, retinal superoxide production and outer retina-specific 1/T1 values were both significantly greater than normal and corrected to baseline with MB+LPA therapy. Nondiabetic mice at two ages and 1.2-month diabetic mice (before the appearance of oxidative stress) had similar transretinal 1/T1 profiles. By 2.3 months of diabetes, only outer retinal 1/T1 values were significantly greater than normal and were corrected to baseline with MB+LPA therapy. In mice with healthy photoreceptors, a light quench caused 1/T1 of rods, but not cones, to significantly decrease from their values in the dark. CONCLUSIONS Quench-assisted MRI is a feasible method for noninvasively measuring normal and pathologic production of free radicals in photoreceptors/RPE in vivo.
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Affiliation(s)
- Bruce A Berkowitz
- Department of Anatomy and Cell Biology Wayne State University School of Medicine, Detroit, Michigan, United States 2Department of Ophthalmology, Wayne State University School of Medicine, Detroit, Michigan, United States
| | - Bryce X Bredell
- Department of Anatomy and Cell Biology Wayne State University School of Medicine, Detroit, Michigan, United States
| | - Christopher Davis
- Department of Anatomy and Cell Biology Wayne State University School of Medicine, Detroit, Michigan, United States
| | - Marijana Samardzija
- Laboratory for Retinal Cell Biology, Department of Ophthalmology, University of Zurich, Switzerland
| | - Christian Grimm
- Laboratory for Retinal Cell Biology, Department of Ophthalmology, University of Zurich, Switzerland
| | - Robin Roberts
- Department of Anatomy and Cell Biology Wayne State University School of Medicine, Detroit, Michigan, United States
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12
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O'Connor JPB, Boult JKR, Jamin Y, Babur M, Finegan KG, Williams KJ, Little RA, Jackson A, Parker GJM, Reynolds AR, Waterton JC, Robinson SP. Oxygen-Enhanced MRI Accurately Identifies, Quantifies, and Maps Tumor Hypoxia in Preclinical Cancer Models. Cancer Res 2016; 76:787-95. [PMID: 26659574 PMCID: PMC4757751 DOI: 10.1158/0008-5472.can-15-2062] [Citation(s) in RCA: 115] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2015] [Accepted: 11/09/2015] [Indexed: 01/10/2023]
Abstract
There is a clinical need for noninvasive biomarkers of tumor hypoxia for prognostic and predictive studies, radiotherapy planning, and therapy monitoring. Oxygen-enhanced MRI (OE-MRI) is an emerging imaging technique for quantifying the spatial distribution and extent of tumor oxygen delivery in vivo. In OE-MRI, the longitudinal relaxation rate of protons (ΔR1) changes in proportion to the concentration of molecular oxygen dissolved in plasma or interstitial tissue fluid. Therefore, well-oxygenated tissues show positive ΔR1. We hypothesized that the fraction of tumor tissue refractory to oxygen challenge (lack of positive ΔR1, termed "Oxy-R fraction") would be a robust biomarker of hypoxia in models with varying vascular and hypoxic features. Here, we demonstrate that OE-MRI signals are accurate, precise, and sensitive to changes in tumor pO2 in highly vascular 786-0 renal cancer xenografts. Furthermore, we show that Oxy-R fraction can quantify the hypoxic fraction in multiple models with differing hypoxic and vascular phenotypes, when used in combination with measurements of tumor perfusion. Finally, Oxy-R fraction can detect dynamic changes in hypoxia induced by the vasomodulator agent hydralazine. In contrast, more conventional biomarkers of hypoxia (derived from blood oxygenation-level dependent MRI and dynamic contrast-enhanced MRI) did not relate to tumor hypoxia consistently. Our results show that the Oxy-R fraction accurately quantifies tumor hypoxia noninvasively and is immediately translatable to the clinic.
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Affiliation(s)
- James P B O'Connor
- Institute of Cancer Sciences, University of Manchester, Manchester, United Kingdom. Centre for Imaging Sciences, University of Manchester, Manchester, United Kingdom. Department of Radiology, Christie NHS Foundation Trust, Manchester, United Kingdom. james.o'
| | - Jessica K R Boult
- Division of Radiotherapy and Imaging, The Institute of Cancer Research, London, United Kingdom
| | - Yann Jamin
- Division of Radiotherapy and Imaging, The Institute of Cancer Research, London, United Kingdom
| | - Muhammad Babur
- Manchester Pharmacy School, University of Manchester, Manchester, United Kingdom
| | - Katherine G Finegan
- Manchester Pharmacy School, University of Manchester, Manchester, United Kingdom
| | - Kaye J Williams
- Institute of Cancer Sciences, University of Manchester, Manchester, United Kingdom. Manchester Pharmacy School, University of Manchester, Manchester, United Kingdom
| | - Ross A Little
- Centre for Imaging Sciences, University of Manchester, Manchester, United Kingdom
| | - Alan Jackson
- Centre for Imaging Sciences, University of Manchester, Manchester, United Kingdom
| | - Geoff J M Parker
- Centre for Imaging Sciences, University of Manchester, Manchester, United Kingdom
| | - Andrew R Reynolds
- Tumour Biology Team, Breakthrough Breast Cancer Research Centre, The Institute of Cancer Research, London, United Kingdom
| | - John C Waterton
- Centre for Imaging Sciences, University of Manchester, Manchester, United Kingdom
| | - Simon P Robinson
- Division of Radiotherapy and Imaging, The Institute of Cancer Research, London, United Kingdom
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13
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Abstract
Oxygen plays a fundamental role in functional magnetic resonance imaging (FMRI). Blood oxygenation level-dependent (BOLD) imaging is the foundation stone of all FMRI and is still the essential workhorse of the vast majority of FMRI procedures. Hemoglobin may provide the magnetic properties that allow the technique to work, but it is oxygen that allows the contrast to effectively be switched on or off, and it is oxygen that we are interested in tracking in order to observe the oxygen metabolism changes. In general the changes in venous oxygen saturation are observed in order to infer changes in the correlated mechanisms, which can include changes in cerebral blood flow, metabolism, and the fraction of inspired oxygen. By independently manipulating the fraction of inspired oxygen it is possible to alter the amount of dissolved oxygen in the plasma, the venous saturation, or even the blood flow. The effects that these changes have on the observed MRI signal can be either a help or a hindrance depending on how well the changes induced are understood. The administration of supplemental inspired oxygen is in a unique position to provide a flexible, noninvasive, inexpensive, patient-friendly addition to the MRI toolkit to enable investigations to look beyond statistics and regions of interest, and actually produce calibrated, targeted measurements of blood flow, metabolism or pathology.
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Affiliation(s)
- Daniel Bulte
- FMRIB Centre, John Radcliffe Hospital, University of Oxford, Oxford, UK.
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14
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Ma Y, Berman AJ, Pike GB. The effect of dissolved oxygen on the relaxation rates of blood plasma: Implications for hyperoxia calibrated BOLD. Magn Reson Med 2015; 76:1905-1911. [DOI: 10.1002/mrm.26069] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2015] [Revised: 10/05/2015] [Accepted: 11/02/2015] [Indexed: 12/18/2022]
Affiliation(s)
- Yuhan Ma
- McConnell Brain Imaging Centre, Montreal Neurological Institute, McGill University; Montreal Quebec Canada
| | - Avery J.L. Berman
- McConnell Brain Imaging Centre, Montreal Neurological Institute, McGill University; Montreal Quebec Canada
- Department of Radiology and Hotchkiss Brain Institute; University of Calgary; Calgary Alberta Canada
| | - G. Bruce Pike
- Department of Radiology and Hotchkiss Brain Institute; University of Calgary; Calgary Alberta Canada
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15
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Song Y, Cho G, Chun SI, Baek JH, Cho H, Kim YR, Park SB, Kim JK. Oxygen-induced frequency shifts in hyperoxia: a significant component of BOLD signal. NMR IN BIOMEDICINE 2014; 27:835-842. [PMID: 24828299 DOI: 10.1002/nbm.3128] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2013] [Revised: 03/05/2014] [Accepted: 04/01/2014] [Indexed: 06/03/2023]
Abstract
In comparison to the well-documented significance of intravascular deoxyhemoglobin (deoxyHgb), the effects of dissolved oxygen on the blood-oxygen-level-dependent (BOLD) signal have not been widely reported. Based on the fact that the prolonged inspiration of high oxygen fraction gas can result in up to a sixfold increase of the baseline tissue oxygenation, the current study focused on the influence of dissolved oxygen on the BOLD signal during hyperoxia. As results, our in vitro study revealed that the r1 and r2 (relaxivities) of the oxygen-treated serum were 0.22 mM(-1) · s(-1) and 0.19 mM(-1) · s(-1) , respectively. In an in vivo experiment, hyperoxic respiration induced negative BOLD contrast (i.e. signal decrease) in 18-42% of measured brain regions, voxels with accompanying significant decreases in both the T(*)2 (-12.1% to -19.4%) and T1 (-5.8% to -3.3%) relaxation times. In contrast, the T(*)2 relaxation time significantly increased (11.2% to 14.0%) for the voxels displaying positive BOLD contrast (in 41-50% of the measured brain), which reflected a hyperoxygenation-induced reduction in tissue deoxyHgb concentration. These data imply that hyperoxia-driven BOLD signal changes are primarily determined by the counteracting effects of extravascular oxygen and intravascular deoxyHgb. Oxygen-induced magnetic susceptibility was further demonstrated by the study of 1 min hypoxia, which induced BOLD signal changes opposite to those under hyperoxia. Vasoconstriction was more common in voxels with negative BOLD contrast than in voxels with positive contrast (% change of blood volume, -9.8% to -12.8% versus 2.0% to 2.2%), which further suggests that negative BOLD contrast is mainly evoked by an increase in extravascular oxygen concentration. Conclusively, frequency shifts, which are induced by the accumulation of oxygen molecules and associated magnetic field inhomogeneity, are a significant source of the negative BOLD contrast during hyperoxia.
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Affiliation(s)
- Youngkyu Song
- Division of Magnetic Resonance, Korea Basic Science Institute, Cheongwon, Chungbuk, South Korea
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16
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Chiu CD, Chen CCV, Shen CC, Chin LT, Ma HI, Chuang HY, Cho DY, Chu CH, Chang C. Hyperglycemia exacerbates intracerebral hemorrhage via the downregulation of aquaporin-4: temporal assessment with magnetic resonance imaging. Stroke 2013; 44:1682-9. [PMID: 23592763 DOI: 10.1161/strokeaha.113.675983] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
BACKGROUND AND PURPOSE Intracerebral hemorrhage (ICH) is associated with high mortality and neurological deficits, and concurrent hyperglycemia usually worsens clinical outcomes. Aquaporin-4 (AQP-4) is important in cerebral water movement. Our aim was to investigate the role of AQP-4 in hyperglycemic ICH. METHODS Hyperglycemia was induced by intraperitoneal injection of streptozotocin (STZ; 60 mg/kg) in adult Sprague-Dawley male rats. ICH was induced by stereotaxic infusion of collagenase/heparin into the right striatum. One set of rats was repeatedly monitored by MRI at 1, 4, and 7 days after ICH induction so as to acquire information on the formation of hematoma and edema. Another set of rats was killed and brains were examined for differences in the degree of hemorrhage and edema, water content, blood-brain barrier destruction, and AQP-4 expression. RESULTS Hyperglycemia ICH rats exhibited increased brain water content, more severe blood-brain barrier destruction, and greater vasogenic edema as seen on diffusion-weighted MRI. Significant downregulation of AQP-4 was observed in STZ-treated rats after ICH as compared with non-STZ-treated rats. Apoptosis was greater on day 1 after ICH in STZ-treated rats. CONCLUSIONS The expression of AQP-4 in the brain is downregulated in hyperglycemic rats as compared with normoglycemic rats after ICH. This change is accompanied by increased vasogenic brain edema and more severe blood-brain barrier destruction.
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Affiliation(s)
- Cheng-Di Chiu
- Graduate Institute of Medical Sciences, National Defense Medical Center, Taipei, Taiwan
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17
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Mark CI, Fisher JA, Pike GB. Improved fMRI calibration: precisely controlled hyperoxic versus hypercapnic stimuli. Neuroimage 2010; 54:1102-11. [PMID: 20828623 DOI: 10.1016/j.neuroimage.2010.08.070] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2010] [Revised: 07/11/2010] [Accepted: 08/31/2010] [Indexed: 10/19/2022] Open
Abstract
The calibration of functional magnetic resonance imaging (fMRI) for the estimation of neuronal activation-induced changes in cerebral metabolic rate of oxygen (CMRO(2)) has been achieved through hypercapnic-induced iso-metabolic increases in cerebral blood flow (CBF). Hypercapnia (HC) has been traditionally implemented through alterations in the fixed inspired fractional concentrations of carbon dioxide (F(I)CO(2)) without otherwise controlling end-tidal partial pressures of carbon dioxide (P(ET)CO(2)) or oxygen (P(ET)O(2)). There are several shortcomings to the use of this manual HC method that may be improved by using precise targeting of P(ET)CO(2) while maintaining iso-oxia. Similarly, precise control of blood gases can be used to induce isocapnic hyperoxia (HO) to reduce venous deoxyhaemoglobin (dHb) and thus increase BOLD signals, without appreciably altering CMRO(2) or CBF. The aim of our study was to use precise end-tidal targeting to compare the calibration of BOLD signals under an isocapnic hyperoxic protocol (HOP) (rises in P(ET)O(2) to 140, 240 and 340 mm Hg from baseline) to that of an iso-oxic hypercapnic protocol (HCP) (rises in P(ET)CO(2) of 3, 5, 7 and 9 mm Hg from baseline). Nine healthy volunteers were imaged at 3T while monitoring end-tidal gas concentrations and simultaneously measuring BOLD and CBF signals, via arterial spin labeling (ASL), during graded HCP and HOP, alternating with normocapnic states in a blocked experimental design. The variability of the calibration constant obtained under HOP (M(HOP)) was 0.3-0.5 that of the HCP one (M(HCP)). In addition, M-variances with precise gas targeting (M(HCP) and M(HOP)) were less than those reported in studies using traditional F(I)CO(2) and F(I)O(2) methods (M(HC) and M(HO), respectively). We conclude that precise controlled gas delivery markedly improves BOLD-calibration for fMRI studies of oxygen metabolism with both the HCP and the more precise HOP-alternative.
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Affiliation(s)
- Clarisse I Mark
- McConnell Brain Imaging Center, Montreal Neurological Institute, McGill University, Montreal, Quebec, Canada.
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18
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Evidence for a critical role of panretinal pathophysiology in experimental ROP. Doc Ophthalmol 2009; 120:13-24. [PMID: 19506927 DOI: 10.1007/s10633-009-9175-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2009] [Accepted: 05/22/2009] [Indexed: 10/20/2022]
Abstract
In this review, we summarize our in vivo studies of retinal pathophysiology in experimental models of retinopathy of prematurity, which were largely focused on the temporal and spatial links between retinal neovascularization (NV), vascular oxygenation, and intraretinal ion regulation. These studies were made possible through the use of magnetic resonance methods. Prior to the phenotype change from normal vessel development to NV, we found little support for a pathogenic role of focal retinal hypoxia at the border of vascular and avascular retina. However, key links were found between retinal NV and functional panretinal defects in both oxygenation to a provocation and intraretinal ion regulation. Through a treatment which reduced NV incidence but not panretinal pathophysiology, proliferative disease was found to last longer than that in the untreated group. These considerations provide compelling evidence that clinical attention directed toward reducing retinal NV should include approaches that reduce functional panretinal pathophysiology.
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19
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Chiarelli PA, Bulte DP, Wise R, Gallichan D, Jezzard P. A calibration method for quantitative BOLD fMRI based on hyperoxia. Neuroimage 2007; 37:808-20. [PMID: 17632016 DOI: 10.1016/j.neuroimage.2007.05.033] [Citation(s) in RCA: 143] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2006] [Revised: 05/01/2007] [Accepted: 05/10/2007] [Indexed: 10/23/2022] Open
Abstract
The estimation of changes in CMR(O2) using functional MRI involves an essential calibration step using a vasoactive agent to induce an isometabolic change in CBF. This calibration procedure is performed most commonly using hypercapnia as the isometabolic stimulus. However, hypercapnia possesses a number of detrimental side effects. Here, a new method is presented using hyperoxia to perform the same calibration step. This procedure requires independent measurement of Pa(O2), the BOLD signal, and CBF. We demonstrate that this method yields results that are comparable to those derived using other methods. Further, the hyperoxia technique is able to provide an estimate of the calibration constant that has lower overall intersubject and intersession variability compared to the hypercapnia approach.
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Affiliation(s)
- Peter A Chiarelli
- FMRIB Centre, Department of Clinical Neurology, University of Oxford, John Radcliffe Hospital, Oxford, OX3 9DU, UK
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20
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Abstract
Graded levels of supplemental inspired oxygen were investigated for their viability as a noninvasive method of obtaining intravascular magnetic resonance image contrast. Administered hyperoxia has been shown to be effective as a blood oxygenation level-dependent contrast agent for magnetic resonance imaging (MRI); however, it is known that high levels of inspired fraction of oxygen result in regionally decreased perfusion in the brain potentially confounding the possibility of using hyperoxia as a means of measuring blood flow and volume. Although the effects of hypoxia on blood flow have been extensively studied, the hyperoxic regime between normoxia and 100% inspired oxygen has been only intermittently studied. Subjects were studied at four levels of hyperoxia induced during a single session while perfusion was measured using arterial spin labelling MRI. Reductions in regional perfusion of grey matter were found to occur even at moderate levels of hyperoxia; however, perfusion changes at all oxygen levels were relatively mild (less than 10%) supporting the viability of hyperoxia-induced contrast.
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Affiliation(s)
- Daniel P Bulte
- FMRIB Centre, Department of Clinical Neurology, University of Oxford, Oxford, UK.
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21
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Matsumoto KI, Bernardo M, Subramanian S, Choyke P, Mitchell JB, Krishna MC, Lizak MJ. MR assessment of changes of tumor in response to hyperbaric oxygen treatment. Magn Reson Med 2006; 56:240-6. [PMID: 16795082 DOI: 10.1002/mrm.20961] [Citation(s) in RCA: 83] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Enhancement of image intensity, using the T1-weighted spoiled gradient-echo (SPGR) sequence, was measured in SCC tumor implanted in the flank of C3H mice while they were subjected to several types of oxygenation challenges inside a hyperbaric chamber designed and constructed to fit in an MRI resonator. The central portions of the tumor gave a positive enhancement, while the periphery showed signal reduction during both normobaric (NBO) and hyperbaric (HBO) oxygen challenges. In the contralateral normal leg, nearly 70% of the region showed a decrease in intensity, and the rest showed a positive enhancement. The positive signal enhancement was markedly greater under HBO compared to NBO. Calculated R1, R2, and M0 maps from multivariate fitting of images acquired by a multislice multiecho (MSME) sequence with variable TR before, during, and after HBO treatment confirm that the source of SPGR signal enhancement in the tumor is associated with shortening of T1.
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Affiliation(s)
- Ken-ichiro Matsumoto
- Radiation Biology Branch, Center for Cancer Research, National Cancer Institute, Bethesda, Maryland 20892-1002, USA
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Zaharchuk G, Martin AJ, Rosenthal G, Manley GT, Dillon WP. Measurement of cerebrospinal fluid oxygen partial pressure in humans using MRI. Magn Reson Med 2005; 54:113-21. [PMID: 15968660 DOI: 10.1002/mrm.20546] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Fluid-attenuated inversion recovery (FLAIR) images obtained during the administration of supplemental oxygen demonstrate a hyperintense signal within the cerebrospinal fluid (CSF) that is likely caused by T1 changes induced by paramagnetic molecular oxygen. Previous studies demonstrated a linear relationship between the longitudinal relaxation rate (R1 = 1/T1) and oxygen content, which permits quantification of the CSF oxygen partial pressure (P(csf)O2). In the current study, CSF T1 was measured at 1.5 T in the lateral ventricles, third ventricle, cortical sulci, and basilar cisterns of eight normal subjects breathing room air or 100% oxygen. Phantom studies performed with artificial CSF enabled absolute P(csf)O2 quantitation. Regional P(csf)O2 differences on room air were observed, from 65 +/- 27 mmHg in the basilar cisterns to 130 +/- 49 mmHg in the third ventricle. During 100% oxygen, P(csf)O2 increases of 155 +/- 45 and 124 +/- 34 mmHg were measured in the basilar cisterns and cortical sulci, respectively, with no change observed in the lateral or third ventricles. P(csf)O2 measurements in humans breathing room air or 100% oxygen using a T1 method are comparable to results from invasive human and animal studies. Similar approaches could be applied to noninvasively monitor oxygenation in many acellular, low-protein body fluids.
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Affiliation(s)
- Greg Zaharchuk
- Department of Radiology, University of California-San Francisco, San Francisco, California 94143-0628, USA
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23
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Berkowitz BA, Luan H, Gupta RR, Pacheco D, Seidner A, Roberts R, Liggett J, Knoerzer DL, Connor JR, Du Y, Kern TS, Ito Y. Regulation of the early subnormal retinal oxygenation response in experimental diabetes by inducible nitric oxide synthase. Diabetes 2004; 53:173-8. [PMID: 14693712 DOI: 10.2337/diabetes.53.1.173] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
We aimed to test the hypothesis that the inducible form of nitric oxide synthase (iNOS) contributes to the development of an early subnormal retinal oxygenation response in preclinical models of diabetic retinopathy. In urethane anesthetized Sprague Dawley rats or C57BL/6 mice, functional magnetic resonance imaging was used to noninvasively measure the change in retinal oxygen tension (Delta PO(2)) during a carbogen-inhalation challenge. In the rat experiments, the retinal Delta PO(2) of the following groups were compared: control rats (n = 9), 3-month diabetic rats (n = 5), and 3-month diabetic rats treated orally with L-N(6)-(1-iminoethyl)lysine 5-tetrazole amide, a prodrug of an inhibitor of iNOS (n = 6). In addition, the retinal Delta PO(2) of the following mouse groups were compared: C57BL/6 mice (n = 20), C57BL/6-Nos2(tm1 Lau) mice (n = 10), 4-month diabetic mice (n = 13), and 4-month diabetic knockout mice (n = 6). Only the Delta PO(2) of the superior hemiretina of the diabetic rat and mice groups were significantly subnormal (P < 0.05). The superior Delta PO(2) of the diabetic rats treated with the prodrug was not significantly (P > 0.05) different from their respective normal controls. In the mice experiments, the superior retinal Delta PO(2) of the iNOS null mice was not statistically different (P > 0.05) from that of normal control mice. iNOS is required for the development of an early subnormal Delta PO(2) in experimental diabetic retinopathy.
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Affiliation(s)
- Bruce A Berkowitz
- Department of Anatomy and Cell Biology, Wayne State University, Detroit, Michigan 48201, USA.
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24
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Brylla E, Tscheudschilsuren G, Santos AN, Nieber K, Spanel-Borowski K, Aust G. Differences between retinal and choroidal microvascular endothelial cells (MVECs) under normal and hypoxic conditions. Exp Eye Res 2003; 77:527-35. [PMID: 14550394 DOI: 10.1016/s0014-4835(03)00219-7] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The morphological and functional differences between the retinal and choroidal vascular bed raise the question of whether the smallest functional unit, the microvascular endothelial cell (MVEC), also differs in its basal characteristics. Here, we examined bovine retinal and choroidal MVECs (rMVECs, cMVECs) for the presence and regulation of angiogenic mediators and their receptors, and cytokines at the mRNA level using quantitative RT-PCR and differential display. Vascular endothelial growth factor (VEGF) mRNA was expressed in both rMVECs and cMVECs. The basal and hypoxia-increased VEGF mRNA levels were significantly higher in cMVECs, which may indicate a higher capacity for autocrine stimulation in these cells. The mRNA for two VEGF receptors, Flt-1 and Flk-1, was present in rMVECs and cMVECs. Interestingly, rMVECs expressed higher Flt-1 but lower Flk-1 mRNA levels compared to cMVECs. Examining the angiopoietin (Ang)/Tie-2 system, we only detected Ang-1 mRNA at very low levels. While Ang-2 mRNA levels were high in both rMVECs and cMVECs, rMVECs expressed 2-3 times the basal and hypoxia-upregulated Ang-2 mRNA levels than did cMVECs. No difference was found in basal Tie-2 mRNA levels. rMVECs are the more potent producers of macrophage colony-stimulating factor (M-CSF) and granulocyte-macrophage CSF (GM-CSF), whereas cMVECs expressed higher RANTES mRNA levels. In our second approach - screening rMVECs and cMVECs for differentially expressed genes - we found liprin-beta1, calnexin, and sushi-repeat-containing protein, x chromosome (SRPX) mRNA in both MVEC types at varying levels. In summary, MVECs from the retinal and choroidal vascular beds showed quantitative differences in angiogenic regulator expression and in their capability to produce cytokines.
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Affiliation(s)
- Elke Brylla
- Institute of Anatomy, University of Leipzig, Ph.-Rosenthal-Str. 55, D-04103 Leipzig, Germany
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25
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Janne d'Othée B, Rachmuth G, Munasinghe J, Lang EV. The effect of hyperoxygenation on T1 relaxation time in vitro. Acad Radiol 2003; 10:854-60. [PMID: 12945919 DOI: 10.1016/s1076-6332(03)00004-7] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
RATIONALE AND OBJECTIVES Ventilation with high oxygen (O2) concentrations has been shown to decrease T1 in blood and tissues of patients. This study aims to assess the effect of hyperoxygenation on the T1 relaxation time of blood and other physiologic solutions. MATERIALS AND METHODS Varied gaseous mixtures of O2 and air between 21% and 100% O2 were created using an experimental circuit at room temperature, and used to saturate human blood, plasma, or normal saline. The samples were studied using an 8.45-Tesla magnetic resonance (MR) system and a 1.5-Tesla clinical MR scanner. RESULTS MR spectroscopy at 8.45 Tesla showed that the percentage of O2 chosen for saturation correlated negatively with T1 (R2 = 1.00 for blood, 0.99 for plasma, and 1.00 for normal saline). The reduction in T1 between solutions saturated with 21% and 100% O2 was 487 milliseconds (22% of the baseline T1 value) for blood, 391 milliseconds (15%) for plasma and 622 milliseconds (19%) for saline. Similarly, MR measurements at 1.5 Tesla showed T1 reduction with increasing O2 concentration. Conclusion. The decreasing T1 in blood depends strongly on the fraction of dissolved O2 in solution and is largely independent of the hemoglobin content.
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Affiliation(s)
- Bertrand Janne d'Othée
- Department of Radiology - W/CC 335, Beth Israel Deaconess Medical Center, 330 Brookline Avenue, Boston, MA 02215-5400, USA
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26
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Abstract
Assessment of the oxygenation status of brain tumors has been studied increasingly with imaging techniques in light of recent advances in oncology. Tumor oxygen tension is a critical factor influencing the effectiveness of radiation and chemotherapy and malignant progression. Hypoxic tumors are resistant to treatment, and prognostic value of tumor oxygen status is shown in head and neck tumors. Strategies increasing the tumor oxygenation are being investigated to overcome the compromising [figure: see text] effect of hypoxia on tumor treatment. Administration of nicotinamide and inhalation of various high oxygen concentrations have been implemented. Existing methods for assessment of tissue oxygen level are either invasive or insufficient. Accurate and noninvasive means to measure tumor oxygenation are needed for treatment planning, identification of patients who might benefit from oxygenation strategies, and assessing the efficacy of interventions aimed to increase the radiosensitivity of tumors. Of the various imaging techniques used to assess tissue oxygenation, MR spectroscopy and MR imaging are widely available, noninvasive, and clinically applicable techniques. Tumor hypoxia is related closely to insufficient blood flow through chaotic and partially nonfunctional tumor vasculature and the distance between the capillaries and the tumor cells. Information on characteristics of tumor vasculature such as blood volume, perfusion, and increased capillary permeability can be provided with MR imaging. MR imaging techniques can provide a measure of capillary permeability based on contrast enhancement and relative cerebral blood volume estimates using dynamic susceptibility MR imaging. Blood oxygen level dependent contrast MR imaging using gradient echo sequence is intrinsically sensitive to changes in blood oxygen level. Animal models using blood oxygen level-dependent contrast imaging reveal the different responses of normal and tumor vasculature under hyperoxia. Normobaric hyperoxia is used in MR studies as a method to produce MR contrast in tissues. Increased T2* signal intensity of brain tissue has been observed using blood oxygen level-dependent contrast MR imaging. Dynamic blood oxygen level-dependent contrast MR imaging during hyperoxia is suggested to image tumor oxygenation. Quantification of cerebral oxygen saturation using blood oxygen level-dependent MR imaging also has been reported. Quantification of cerebral blood oxygen saturation using MR imaging has promising clinical applications; however, technical difficulties have to be resolved. Blood oxygen level dependent MR imaging is an emerging technique to evaluate the cerebral blood oxygen saturation, and it has the potential and versatility to assess oxygenation status of brain tumors. Upon improvement and validation of current MR techniques, better diagnostic, prognostic, and treatment monitoring capabilities can be provided for patients with brain tumors.
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Affiliation(s)
- F Zerrin Yetkin
- Division of Neuroradiology, Department of Radiology, University of Texas Southwestern Medical Center at Dallas, Dallas, TX 75390-8896, USA.
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27
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Berkowitz BA, McDonald C, Ito Y, Tofts PS, Latif Z, Gross J. Measuring the human retinal oxygenation response to a hyperoxic challenge using MRI: eliminating blinking artifacts and demonstrating proof of concept. Magn Reson Med 2001; 46:412-6. [PMID: 11477648 DOI: 10.1002/mrm.1206] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The retinal oxygenation response to a hyperoxic challenge measured using MRI appears to be an early and accurate marker of retinopathy risk in experimental models, with promising clinical potential. However, the application of this technique in humans is limited by blinking artifacts that can confound detection of subtle signal intensity changes. We asked subjects to refrain from blinking during a 12-s fast low-angle shot (FLASH) image, and to blink if needed during the following 3-s rest period. This no-blink blink cycle was repeated sequentially 20 times during either room-air or 100% oxygen breathing. Significant change (P < 0.05) was detected for the first time from the resultant blinking-artifact-free images in the preretinal vitreous oxygen tension (upper limit of about 13 mm Hg (1.8 KPa, N = 3)) following a 10-min hyperoxic inhalation challenge. These results provide the proof-of-concept data needed for future MRI evaluation of the retinal oxygenation response and human retinopathy, such as diabetic retinopathy.
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Affiliation(s)
- B A Berkowitz
- Department of Anatomy and Cell Biology, Wayne State University, Detroit, Michigan 48201, USA.
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28
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Abstract
In this paper, we summarize the development and application of two novel magnetic resonance based measurements of retinal oxygenation in experimental models of retinopathy, including diabetic retinopathy and retinopathy of prematurity. We use 19F-NMR and a small (microl) perfluorocarbon drop positioned in the preretinal vitreous space to make PO2 measurement of the inner retina. In addition, we use magnetic resonance imaging (MRI) to accurately and non-invasively measure the change in the preretinal PO2 (DeltaPO2) following the shift from breathing room air to a hyperoxic inhalation challenge. The advantages and disadvantages of each method are discussed. New applications of these techniques in the newborn rat and adult mouse are presented. We expect such studies to motivate future MRI oxygenation studies of human retinopathy, including diabetic retinopathy and retinopathy of prematurity.
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Affiliation(s)
- Y Ito
- Department of Anatomy and Cell Biology, School of Medicine, Wayne State University, 540 E. Canfield, Detroit, MI 77204-6052, USA
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Kashikura K, Kershaw J, Kashikura A, Zhang X, Matsuura T, Kanno I. Hyperoxia modified activation-induced blood oxygenation level-dependent response of human visual cortex (V1): an event-related functional magnetic resonance imaging study. Neurosci Lett 2001; 299:53-6. [PMID: 11166936 DOI: 10.1016/s0304-3940(00)01781-x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
To investigate the effect that hyperoxia has on the blood oxygenation level-dependent (BOLD) response to visual stimulation of human V1, an event-related functional magnetic resonance imaging technique was applied. The event-related paradigm consisted of 2 s of stimulation by a checkerboard reversing at a frequency of 8 Hz, followed by 18 s of control scans. The peak height and peak time of the BOLD response curves were compared under normoxic and hyperoxic conditions. It was found that the peak height was larger and the peak time shorter for hyperoxia than for normoxia. These results suggest that hyperoxia modified the activation-induced hemodynamic response of human V1.
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Affiliation(s)
- K Kashikura
- Akita Laboratory, Japan Science and Technology Corporation (JST), 6-10 Senshu-kubota cho, Akita 010-0874, Japan.
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30
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Kashikura K, Kershaw J, Kashikura A, Matsuura T, Kanno I. Hyperoxia-enhanced activation-induced hemodynamic response in human VI: an fMRI study. Neuroreport 2000; 11:903-6. [PMID: 10790852 DOI: 10.1097/00001756-200004070-00001] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The effect hyperoxia had on the hemodynamic response to visual stimulation (black and white checkerboard alternating at a frequency of 8 Hz) of human VI was investigated using a blood oxygenation level-dependent (BOLD) contrast with an fMRI technique. Data were acquired with a 5 on/5 off block paradigm using single-shot gradient-echo echo-planar imaging. Using a two-tailed paired t-test (p < 0.05, n = 13) it was found that the mean percentage signal change and the mean number of activated pixels was significantly increased for hyperoxia (5.7 +/- 0.9, 187 +/- 73, mean +/- SD) relative to those for normoxia (5.4 +/- 0.9, 168 +/- 58). We believe that these results indicate that hyperoxia enhances the activation-induced hemodynamic response in human VI.
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Affiliation(s)
- K Kashikura
- Akita Laboratory, Japan Science and Technology Corporation (JST), Japan
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Noseworthy MD, Kim JK, Stainsby JA, Stanisz GJ, Wright GA. Tracking oxygen effects on MR signal in blood and skeletal muscle during hyperoxia exposure. J Magn Reson Imaging 1999; 9:814-20. [PMID: 10373029 DOI: 10.1002/(sici)1522-2586(199906)9:6<814::aid-jmri8>3.0.co;2-5] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Blood and muscle T1 and T2 relaxivity was examined under normoxic (air; 20.8% O2) and hyperoxic (100% O2) conditions to determine whether the oxygenation state of blood in the large vessels and in the microcirculation can be monitored in vivo. The femoral artery/vein and the soleus and gastrocnemius muscles were examined in healthy human male volunteers. Arterial blood T1 decreased with hyperoxia, while venous blood T2 increased, due to increased dissolved O2 and decreased deoxyhemoglobin, respectively. A biexponential T2 model of muscle is proposed, where the short T2 component reflects primarily the intracellular and interstitial compartments (in fast exchange), and the long T2 reflects blood. In this model, the long T2 component increased with hyperoxia exposure. This was more evident in slow twitch (soleus) than in fast twitch (gastrocnemius) muscle. It is concluded that changes in the long T2 component reflect change in the microcirculation oxygenation state.
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Affiliation(s)
- M D Noseworthy
- The Department of Medical Biophysics, University of Toronto, Imaging Research, Sunnybrook Health Science Centre, Ontario, Canada.
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