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Epel B, Viswakarma N, Hameed S, Freidin MM, Abrams CK, Kotecha M. Assessment of blood-brain barrier leakage and brain oxygenation in Connexin-32 knockout mice with systemic neuroinflammation using pulse electron paramagnetic resonance imaging techniques. Magn Reson Med 2024; 91:2519-2531. [PMID: 38193348 PMCID: PMC10997480 DOI: 10.1002/mrm.29994] [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: 08/11/2023] [Revised: 11/30/2023] [Accepted: 12/13/2023] [Indexed: 01/10/2024]
Abstract
PURPOSE The determination of blood-brain barrier (BBB) integrity and partial pressure of oxygen (pO2) in the brain is of substantial interest in several neurological applications. This study aimed to assess the feasibility of using trityl OX071-based pulse electron paramagnetic resonance imaging (pEPRI) to provide a quantitative estimate of BBB integrity and pO2 maps in mouse brains as a function of neuroinflammatory disease progression. METHODS Five Connexin-32 (Cx32)-knockout (KO) mice were injected with lipopolysaccharide to induce neuroinflammation for imaging. Three wild-type mice were also used to optimize the imaging procedure and as control animals. An additional seven Cx32-KO mice were used to establish the BBB leakage of trityl using the colorimetric assay. All pEPRI experiments were performed using a preclinical instrument, JIVA-25 (25 mT/720 MHz), at times t = 0, 4, and 6 h following lipopolysaccharide injection. Two pEPRI imaging techniques were used: (a) single-point imaging for obtaining spatial maps to outline the brain and calculate BBB leakage using the signal amplitude, and (b) inversion-recovery electron spin echo for obtaining pO2 maps. RESULTS A statistically significant change in BBB leakage was found using pEPRI with the progression of inflammation in Cx32 KO animals. However, the change in pO2 values with the progression of inflammation for these animals was not statistically significant. CONCLUSIONS For the first time, we show the ability of pEPRI to provide pO2 maps in mouse brains noninvasively, along with a quantitative assessment of BBB leakage. We expect this study to open new queries from the field to explore the pathology of many neurological diseases and provide a path to new treatments.
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Affiliation(s)
- Boris Epel
- Oxygen Measurement Core, O2M Technologies, LLC, Chicago, Illinois, USA
- Department of Radiation and Cellular Oncology, The University of Chicago, Chicago, Illinois, USA
| | - Navin Viswakarma
- Oxygen Measurement Core, O2M Technologies, LLC, Chicago, Illinois, USA
| | - Safa Hameed
- Oxygen Measurement Core, O2M Technologies, LLC, Chicago, Illinois, USA
| | - Mona M Freidin
- Department of Neurology and Rehabilitation, University of Illinois at Chicago, Chicago, Illinois, USA
| | - Charles K Abrams
- Department of Neurology and Rehabilitation, University of Illinois at Chicago, Chicago, Illinois, USA
- Richard and Loan Hill Department of Biomedical Engineering, University of Illinois at Chicago, Chicago, Illinois, USA
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Brender JR, Saida Y, Devasahayam N, Krishna MC, Kishimoto S. Hypoxia Imaging As a Guide for Hypoxia-Modulated and Hypoxia-Activated Therapy. Antioxid Redox Signal 2022; 36:144-159. [PMID: 34428981 PMCID: PMC8856011 DOI: 10.1089/ars.2021.0176] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Accepted: 08/16/2021] [Indexed: 01/03/2023]
Abstract
Significance: Oxygen imaging techniques, which can probe the spatiotemporal heterogeneity of tumor oxygenation, could be of significant clinical utility in radiation treatment planning and in evaluating the effectiveness of hypoxia-activated prodrugs. To fulfill these goals, oxygen imaging techniques should be noninvasive, quantitative, and capable of serial imaging, as well as having sufficient temporal resolution to detect the dynamics of tumor oxygenation to distinguish regions of chronic and acute hypoxia. Recent Advances: No current technique meets all these requirements, although all have strengths in certain areas. The current status of positron emission tomography (PET)-based hypoxia imaging, oxygen-enhanced magnetic resonance imaging (MRI), 19F MRI, and electron paramagnetic resonance (EPR) oximetry are reviewed along with their strengths and weaknesses for planning hypoxia-guided, intensity-modulated radiation therapy and detecting treatment response for hypoxia-targeted prodrugs. Critical Issues: Spatial and temporal resolution emerges as a major concern for these areas along with specificity and quantitative response. Although multiple oxygen imaging techniques have reached the investigative stage, clinical trials to test the therapeutic effectiveness of hypoxia imaging have been limited. Future Directions: Imaging elements of the redox environment besides oxygen by EPR and hyperpolarized MRI may have a significant impact on our understanding of the basic biology of the reactive oxygen species response and may extend treatment possibilities.
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Affiliation(s)
- Jeffrey R. Brender
- Radiation Biology Branch, Center for Cancer Research, National
Institutes of Health, Bethesda, Maryland, USA
| | - Yu Saida
- Radiation Biology Branch, Center for Cancer Research, National
Institutes of Health, Bethesda, Maryland, USA
| | - Nallathamby Devasahayam
- Radiation Biology Branch, Center for Cancer Research, National
Institutes of Health, Bethesda, Maryland, USA
| | - Murali C. Krishna
- Radiation Biology Branch, Center for Cancer Research, National
Institutes of Health, Bethesda, Maryland, USA
| | - Shun Kishimoto
- Radiation Biology Branch, Center for Cancer Research, National
Institutes of Health, Bethesda, Maryland, USA
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Biller JR, McPeak JE. EPR Everywhere. APPLIED MAGNETIC RESONANCE 2021; 52:1113-1139. [PMID: 33519097 PMCID: PMC7826499 DOI: 10.1007/s00723-020-01304-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/09/2020] [Revised: 10/16/2020] [Accepted: 12/06/2020] [Indexed: 06/12/2023]
Abstract
This review is inspired by the contributions from the University of Denver group to low-field EPR, in honor of Professor Gareth Eaton's 80th birthday. The goal is to capture the spirit of innovation behind the body of work, especially as it pertains to development of new EPR techniques. The spirit of the DU EPR laboratory is one that never sought to limit what an EPR experiment could be, or how it could be applied. The most well-known example of this is the development and recent commercialization of rapid-scan EPR. Both of the Eatons have made it a point to remain knowledgeable on the newest developments in electronics and instrument design. To that end, our review touches on the use of miniaturized electronics and applications of single-board spectrometers based on software-defined radio (SDR) implementations and single-chip voltage-controlled oscillator (VCO) arrays. We also highlight several non-traditional approaches to the EPR experiment such as an EPR spectrometer with a "wand" form factor for analysis of the OxyChip, the EPR-MOUSE which enables non-destructive in situ analysis of many non-conforming samples, and interferometric EPR and frequency swept EPR as alternatives to classical high Q resonant structures.
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Affiliation(s)
| | - Joseph E. McPeak
- University of Denver, Denver, CO 80210 USA
- Berlin Joint EPR Laboratory and EPR4Energy, Department Spins in Energy Conversion and Quantum Information Science (ASPINS), Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Hahn-Meitner-Platz 1, 14109 Berlin, Germany
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Jang H, Lu X, Carl M, Searleman AC, Jerban S, Ma Y, von Drygalski A, Chang EY, Du J. True phase quantitative susceptibility mapping using continuous single-point imaging: a feasibility study. Magn Reson Med 2018; 81:1907-1914. [PMID: 30325058 DOI: 10.1002/mrm.27515] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2018] [Revised: 08/09/2018] [Accepted: 08/10/2018] [Indexed: 12/20/2022]
Abstract
PURPOSE In this study, we explore the feasibility of a new imaging scheme for quantitative susceptibility mapping (QSM): continuous single-point imaging (CSPI), which uses a pure phase encoding strategy to achieve true phase imaging and improve QSM accuracy. METHODS The proposed CSPI is a modification of conventional SPI to allow acquisition of multiple echoes in a single scan. Immediately following a phase encoding gradient, the free induction decay is continuously sampled with extremely high temporal resolution to obtain k-space data at a fixed spatial frequency (i.e., at a fixed k-space coordinate). By having near-0 readout duration, CSPI results in a true snapshot of the transverse magnetization at each TE. Additionally, parallel imaging with autocalibration is utilized to reduce scan time, and an optional temporal averaging strategy is presented to improve signal-to-noise ratio for objects with low proton density or short T2* decay. The reconstructed CSPI images were input to a QSM framework based on morphology enabled dipole inversion. RESULT In an experiment performed using iron phantoms, susceptibility estimated using CSPI showed high linearity (R2 = 0.9948) with iron concentration. Additionally, reconstructed CSPI phase images showed much reduced ringing artifact compared with phase images obtained using a frequency encoding strategy. In an ex vivo experiment performed using human tibia samples, estimated susceptibilities ranged from -1.6 to -2.1 ppm, in agreement with values reported in the literature (ranging from -1.2 to -2.2 ppm). CONCLUSION We have demonstrated the feasibility of using CSPI to obtain true phase images for QSM.
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Affiliation(s)
- Hyungseok Jang
- Department of Radiology, University of California San Diego, San Diego, California
| | - Xing Lu
- Department of Radiology, University of California San Diego, San Diego, California.,Institute of Electrical Engineering, Chinese Academy of Science, Beijing, China
| | | | - Adam C Searleman
- Department of Radiology, University of California San Diego, San Diego, California
| | - Saeed Jerban
- Department of Radiology, University of California San Diego, San Diego, California
| | - Yajun Ma
- Department of Radiology, University of California San Diego, San Diego, California
| | - Annette von Drygalski
- Department of Medicine, Division of Hematology/Oncology, University of California, San Diego, California
| | - Eric Y Chang
- Department of Radiology, University of California San Diego, San Diego, California.,Radiology Service, VA San Diego Healthcare System, San Diego, California
| | - Jiang Du
- Department of Radiology, University of California San Diego, San Diego, California
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Jang H, Liu F, Bradshaw T, McMillan AB. Rapid dual-echo ramped hybrid encoding MR-based attenuation correction (dRHE-MRAC) for PET/MR. Magn Reson Med 2018; 79:2912-2922. [PMID: 28971513 PMCID: PMC5843521 DOI: 10.1002/mrm.26953] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2017] [Revised: 08/16/2017] [Accepted: 09/10/2017] [Indexed: 12/18/2022]
Abstract
PURPOSE In this study, we propose a rapid acquisition for MR-based attenuation correction (MRAC) in positron emission tomography (PET)/MR imaging, in which an ultrashort echo time (UTE) image and an out-of-phase echo image are obtained within a single rapid scan (35 s) at high spatial resolution (1 mm3 ), which allows accurate estimation of a pseudo CT image using 4-class tissue classification (discrete bone, discrete air, continuous fat, and continuous water). METHODS In dual-echo ramped hybrid encoding (dRHE), a UTE echo is directly followed by a second out-of-phase echo, in which hybrid spatial encoding combining single-point imaging and 3-dimensional radial frequency encoding is used to improve the quality of both images. Two-point Dixon reconstruction is used to estimate fat- and water-separated images, and UTE images are used to estimate bone. Air and bone segmentation is improved by using multiple UTE images with an advanced hybrid-encoding scheme that allows reconstruction of multiple UTE images. To evaluate the proposed method, dRHE-MRAC PET/MR brain imaging was performed in 10 subjects. Dice coefficients and PET reconstruction errors relative to CT-based attenuation correction were compared with existing system MRAC approaches. RESULTS In dRHE-MRAC, the Dice coefficients for soft tissue, air, and bone were respectively 0.95 ± 0.01, 0.62 ± 0.06, and 0.78 ± 0.05, which was a significantly improved result compared with existing approaches. In most brain regions, dRHE-MRAC showed significantly reduced PET error (less than 1%) with P values less than 0.05. CONCLUSIONS Dual-echo ramped hybrid encoding enables rapid and robust imaging for MRAC with a very rapid acquisition. Magn Reson Med 79:2912-2922, 2018. © 2017 International Society for Magnetic Resonance in Medicine.
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Affiliation(s)
- Hyungseok Jang
- Departments of Radiology, University of Wisconsin School of Medicine and Public Health, 600 Highland Avenue, Madison, Wisconsin 53705-2275
| | - Fang Liu
- Departments of Radiology, University of Wisconsin School of Medicine and Public Health, 600 Highland Avenue, Madison, Wisconsin 53705-2275
| | - Tyler Bradshaw
- Departments of Radiology, University of Wisconsin School of Medicine and Public Health, 600 Highland Avenue, Madison, Wisconsin 53705-2275
| | - Alan B McMillan
- Departments of Radiology, University of Wisconsin School of Medicine and Public Health, 600 Highland Avenue, Madison, Wisconsin 53705-2275
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Jang H, McMillan AB. A rapid and robust gradient measurement technique using dynamic single-point imaging. Magn Reson Med 2016; 78:950-962. [PMID: 27699867 DOI: 10.1002/mrm.26481] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2016] [Revised: 09/01/2016] [Accepted: 09/02/2016] [Indexed: 12/20/2022]
Abstract
PURPOSE We propose a new gradient measurement technique based on dynamic single-point imaging (SPI), which allows simple, rapid, and robust measurement of k-space trajectory. METHODS To enable gradient measurement, we utilize the variable field-of-view (FOV) property of dynamic SPI, which is dependent on gradient shape. First, one-dimensional (1D) dynamic SPI data are acquired from a targeted gradient axis, and then relative FOV scaling factors between 1D images or k-spaces at varying encoding times are found. These relative scaling factors are the relative k-space position that can be used for image reconstruction. The gradient measurement technique also can be used to estimate the gradient impulse response function for reproducible gradient estimation as a linear time invariant system. RESULTS The proposed measurement technique was used to improve reconstructed image quality in 3D ultrashort echo, 2D spiral, and multi-echo bipolar gradient-echo imaging. In multi-echo bipolar gradient-echo imaging, measurement of the k-space trajectory allowed the use of a ramp-sampled trajectory for improved acquisition speed (approximately 30%) and more accurate quantitative fat and water separation in a phantom. CONCLUSION The proposed dynamic SPI-based method allows fast k-space trajectory measurement with a simple implementation and no additional hardware for improved image quality. Magn Reson Med 78:950-962, 2017. © 2016 International Society for Magnetic Resonance in Medicine.
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Affiliation(s)
- Hyungseok Jang
- Department of Radiology, Wisconsin Institute for Medical Research, University of Wisconsin, Madison, Wisconsin, USA.,Department of Electrical and Computer Engineering, University of Wisconsin, Madison, Wisconsin, USA
| | - Alan B McMillan
- Department of Radiology, Wisconsin Institute for Medical Research, University of Wisconsin, Madison, Wisconsin, USA
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Jang H, Wiens CN, McMillan AB. Ramped hybrid encoding for improved ultrashort echo time imaging. Magn Reson Med 2015; 76:814-25. [PMID: 26381890 DOI: 10.1002/mrm.25977] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2015] [Revised: 08/18/2015] [Accepted: 08/18/2015] [Indexed: 12/15/2022]
Abstract
PURPOSE We propose a new acquisition to minimize the per-excitation encoding duration and improve the imaging capability for short T2 * species. METHODS In the proposed ramped hybrid encoding (RHE) technique, gradients are applied before the radiofrequency (RF) pulse as in pointwise encoding time reduction with radial acquisition (PETRA) and zero echo time (ZTE) imaging. However, in RHE, gradients are rapidly ramped after RF excitation to the maximum amplitude to minimize encoding duration. To acquire central k-space data not measured during RF deadtime, RHE uses a hybrid encoding scheme similar to PETRA. A new gradient calibration method based on single-point imaging was developed to estimate the k-space trajectory and enable robust and high quality reconstruction. RESULTS RHE enables a shorter per-excitation encoding time and provides the highest spatial resolution among ultrashort T2 * imaging methods. In phantom and in vivo experiments, RHE exhibited robust imaging with negligible chemical shift or blurriness caused by T2 * decay and unwanted slice selection. CONCLUSION RHE allows the shortest per-excitation encoding time for ultrashort T2 * imaging, which alleviates the impact of fast T2 * decay occurring during encoding, and enables improved spatial resolution. Magn Reson Med 76:814-825, 2016. © 2015 Wiley Periodicals, Inc.
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Affiliation(s)
- Hyungseok Jang
- Department of Radiology, Wisconsin Institute for Medical Research, University of Wisconsin, Madison, Wisconsin, USA.,Department of Electrical and Computer Engineering, University of Wisconsin, Madison, Wisconsin, USA
| | - Curtis N Wiens
- Department of Radiology, Wisconsin Institute for Medical Research, University of Wisconsin, Madison, Wisconsin, USA
| | - Alan B McMillan
- Department of Radiology, Wisconsin Institute for Medical Research, University of Wisconsin, Madison, Wisconsin, USA
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