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Marino S, Ciurleo R, Bramanti P, Federico A, De Stefano N. 1H-MR spectroscopy in traumatic brain injury. Neurocrit Care 2011; 14:127-33. [PMID: 20737247 DOI: 10.1007/s12028-010-9406-6] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
Traumatic brain injury (TBI) is a common cause of neurological damage and disability. Conventional imaging (CT scan or MRI) is highly sensitive in detecting lesions and provides important clinical information regarding the need for acute intervention. However, abnormalities detected by CT scan or conventional MRI have limited importance in the classification of the degree of clinical severity and in predicting patients' outcome. This can be explained by the widespread microscopic tissue damage occurring after trauma, which is not observable with the conventional structural imaging methods. Advances in neuroimaging over the past two decades have greatly helped in the clinical care and management of patients with TBI. The advent of newer and more sensitive imaging techniques is now being used to better characterize the nature and evolution of injury and the underlying mechanisms that lead to progressive neurodegeneration, recovery or subsequent plasticity. This review will describe the role of proton magnetic resonance spectroscopic (MRS), an advanced MRI technique as related to its use in TBI. Proton MRS is a noninvasive approach that acquires metabolite information reflecting neuronal integrity and function from multiple brain regions and allows to assess clinical severity and to predict disease outcome.
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Affiliation(s)
- Silvia Marino
- IRCCS Centro Neurolesi Bonino-Pulejo, Messina, Italy.
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Casey PA, McKenna MC, Fiskum G, Saraswati M, Robertson CL. Early and sustained alterations in cerebral metabolism after traumatic brain injury in immature rats. J Neurotrauma 2008; 25:603-14. [PMID: 18454682 DOI: 10.1089/neu.2007.0481] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Although studies have shown alterations in cerebral metabolism after traumatic brain injury (TBI), clinical data in the developing brain is limited. We hypothesized that post-traumatic metabolic changes occur early (<24 h) and persist for up to 1 week. Immature rats underwent TBI to the left parietal cortex. Brains were removed at 4 h, 24 h, and 7 days after injury, and separated into ipsilateral (injured) and contralateral (control) hemispheres. Proton nuclear magnetic resonance (NMR) spectra were obtained, and spectra were analyzed for N-acetyl-aspartate (NAA), lactate (Lac), creatine (Cr), choline, and alanine, with metabolite ratios determined (NAA/Cr, Lac/Cr). There were no metabolic differences at any time in sham controls between cerebral hemispheres. At 4 and 24 h, there was an increase in Lac/Cr, reflecting increased glycolysis and/or decreased oxidative metabolism. At 24 h and 7 days, there was a decrease in NAA/Cr, indicating loss of neuronal integrity. The NAA/Lac ratio was decreased ( approximately 15-20%) at all times (4 h, 24 h, 7 days) in the injured hemisphere of TBI rats. In conclusion, metabolic derangements begin early (<24 h) after TBI in the immature rat and are sustained for up to 7 days. Evaluation of early metabolic alterations after TBI could identify novel targets for neuroprotection in the developing brain.
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Affiliation(s)
- Paula A Casey
- Department of Pediatrics, University of Maryland School of Medicine, 22 South Greene Street, Baltimore, MD 21201, USA
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Brooks WM, Friedman SD, Gasparovic C. Magnetic resonance spectroscopy in traumatic brain injury. J Head Trauma Rehabil 2001; 16:149-64. [PMID: 11275576 DOI: 10.1097/00001199-200104000-00005] [Citation(s) in RCA: 81] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Magnetic resonance spectroscopy (MRS) offers a unique non-invasive approach for assessing the metabolic status of the brain in vivo and is particularly suited to studying traumatic brain injury (TBI). In particular, MRS provides a noninvasive means for quantifying such neurochemicals as N-acetylaspartate (NAA), creatine, phosphocreatine, choline, lactate, myo-inositol, glutamine, glutamate, adenosine triphosphate (ATP), and inorganic phosphate in humans following TBI and in animal models. Many of these chemicals have been shown to be perturbed following TBI. NAA, a marker of neuronal integrity, has been shown to be reduced following TBI, reflecting diffuse axonal injury or metabolic depression, and concentrations of NAA predict cognitive outcome. Elevation of choline-containing compounds indicates membrane breakdown or inflammation or both. MRS can also detect alterations in high energy phosphates reflecting the energetic abnormalities seen after TBI. Accordingly, MRS may be useful to monitor cellular response to therapeutic interventions in TBI.
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Affiliation(s)
- W M Brooks
- Clinical and Magnetic Resonance Research Center; Department of Neurosciences, University of New Mexico Health Sciences Center, Albuquerque, 87131, USA.
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Goodman JC, Valadka AB, Gopinath SP, Uzura M, Robertson CS. Extracellular lactate and glucose alterations in the brain after head injury measured by microdialysis. Crit Care Med 1999; 27:1965-73. [PMID: 10507626 DOI: 10.1097/00003246-199909000-00041] [Citation(s) in RCA: 209] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE To study cerebral glucose and lactate metabolism in head-injured patients using microdialysis. DESIGN Prospective, nonrandomized, clinical study. SETTING Neurosurgical intensive care unit in a university-affiliated county hospital. PATIENTS One hundred twenty-six head-injured patients. INTERVENTIONS Cerebral cortical neurochemical monitoring using microdialysis coupled with systemic hemodynamic and oxygenation monitoring, measurement of cerebral perfusion pressure and intracranial pressure, and measurement of global cerebral oxygenation using jugular venous oxygen saturation in all 126 patients. In selected cases, cerebral blood flow was also measured using cortical thermodilution probes in 33 patients, and regional cerebral oxygenation was measured using PO2 probes in 65 patients. MEASUREMENTS AND MAIN RESULTS Elevated extracellular lactate, reduced glucose, and an elevated lactate/glucose ratio were observed with cerebral hypoxia and ischemia. Elevated lactate and an increased lactate/glucose ratio strongly correlated with death. Other more subtle alterations of lactate and glucose were seen early after injury that may reflect compensatory alterations in cerebral metabolism. CONCLUSIONS Clinical neurochemical monitoring of glucose and lactate levels in the extracellular space of the cerebral cortex is technically feasible and provides insight into the bioenergetic status of the brain. Increased lactate and decreased glucose, indicating accelerated glycolysis, commonly occurred with cerebral ischemia or hypoxia, and increased anaerobic glycolysis in this setting is associated with a poor outcome.
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Affiliation(s)
- J C Goodman
- Department of Neurosurgery, Baylor College of Medicine, Houston, TX 77030, USA.
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Golding EM, Robertson CS, Bryan RM. The consequences of traumatic brain injury on cerebral blood flow and autoregulation: a review. Clin Exp Hypertens 1999; 21:299-332. [PMID: 10369378 DOI: 10.3109/10641969909068668] [Citation(s) in RCA: 111] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
In this decade, the brain argueably stands as one of the most exciting and challenging organs to study. Exciting in as far as that it remains an area of research vastly unknown and challenging due to the very nature of its anatomical design: the skull provides a formidable barrier and direct observations of intraparenchymal function in vivo are impractical. Moreover, traumatic brain injury (TBI) brings with it added complexities and nuances. The development of irreversible damage following TBI involves a plethora of biochemical events, including impairment of the cerebral vasculature, which render the brain at risk to secondary insults such as ischemia and intracranial hypertension. The present review will focus on alterations in the cerebrovasculature following TBI, and more specifically on changes in cerebral blood flow (CBF), mediators of CBF including local chemical mediators such as K+, pH and adenosine, endothelial mediators such as nitric oxide and neurogenic mediators such as catecholamines, as well as pressure autoregulation. It is emphasized that further research into these mechanisms may help attenuate the prevalence of secondary insults and therefore improve outcome following TBI.
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Affiliation(s)
- E M Golding
- Department of Neurosurgery, Baylor College of Medicine, Houston, Texas 77030, USA
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Rubin Y, Cecil K, Wehrli S, McIntosh TK, Lenkinski RE, Smith DH. High-resolution 1H NMR spectroscopy following experimental brain trauma. J Neurotrauma 1997; 14:441-9. [PMID: 9257662 DOI: 10.1089/neu.1997.14.441] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
We investigated acute metabolic changes following parasagittal fluid-percussion brain injury in the rat, using high-resolution 1H nuclear magnetic resonance (NMR) spectroscopy. Sixty minutes following brain injury or sham (surgery, no injury) treatment, brains were rapidly removed and the injured and control cortices were isolated (n = 5/group). Isolates of brain cortices were then placed in buffer and studied in a 400-MHz spectrometer with measurements taken every 15 min over a 145-min period. At the initial NMR evaluation (immediately following dissection), we observed significantly lower levels of N-acetyl aspartic acid (NAA) in the injured group compared to the sham group. Surprisingly, a reciprocal increase in the concentration of acetate, a major metabolic product of NAA, was not observed at this timepoint. At subsequent timepoints, a progressive loss of NAA was observed in both injured and sham cortices, presumably due to ischemic conditions of the ex vivo samples. However, this progressive loss of NAA was now accompanied by a commensurate accumulation of acetate. These results suggest that (1) a decrease in the concentration of NAA occurs by 1 h following experimental brain trauma, potentially marking traumatic neural injury; (2) the initial absence of an expected reciprocal increase in acetate concentration may signify rapid utilization of acetate following trauma, potentially for reparative processes; and (3) in contrast to trauma alone, post mortem ischemic conditions may induce an increase in acetate concentrations.
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Affiliation(s)
- Y Rubin
- Radiology Department, Hospital of the University of Pennsylvania, Philadelphia 19104, USA
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Iwamoto Y, Yamaki T, Murakami N, Umeda M, Tanaka C, Higuchi T, Aoki I, Naruse S, Ueda S. Investigation of morphological change of lateral and midline fluid percussion injury in rats, using magnetic resonance imaging. Neurosurgery 1997; 40:163-7. [PMID: 8971838 DOI: 10.1097/00006123-199701000-00036] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
OBJECTIVE Investigating the time course of morphological changes in experimental traumatic brain injury (TBI) in vivo helps to clarify the mechanism of TBI and develop new therapeutic modalities. We examined the morphological changes in experimental TBI, using magnetic resonance imaging (MRI) in a rat model. METHODS We produced lateral fluid percussion injury (LFP) and midline fluid percussion injury (MFP) in rats, using the Yamaki fluid percussion device. The rats were divided into four groups: LFP, MFP, sham LFP, and sham MFP. MRI was performed with a 4.7-T magnetic resonance apparatus 2 days and 90 days after the induction of injury. T1-, T2-, and T2- weighted images were obtained using a surface coil. RESULTS Hemorrhage, contusion, and brain edema in LFP models were detected on the 2nd day after injury, and the necrotic tissue was absorbed and replaced by cerebrospinal fluid on the 90th day. In MFP animals, we detected a small hemorrhage in the corpus callosum with minimal brain edema around the hemorrhage on the 2nd day after injury, and on the 90th day, enlarged ventricles and cisterns were observed, indicating brain atrophy. CONCLUSION MRI, therefore, is useful for plotting morphological changes in experimental TBI in vivo. We report the novel and clinically important finding of brain atrophy after experimental TBI.
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Affiliation(s)
- Y Iwamoto
- Department of Neurosurgery, Kyoto Prefectural University of Medicine, Japan
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Iwamoto Y, Yamaki T, Murakami N, Umeda M, Tanaka C, Higuchi T, Aoki I, Naruse S, Ueda S. Investigation of Morphological Change of Lateral and Midline Fluid Percussion Injury in Rats, Using Magnetic Resonance Imaging. Neurosurgery 1997. [DOI: 10.1227/00006123-199701000-00036] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
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Novack TA, Dillon MC, Jackson WT. Neurochemical mechanisms in brain injury and treatment: a review. J Clin Exp Neuropsychol 1996; 18:685-706. [PMID: 8941854 DOI: 10.1080/01688639608408292] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
This article reviews cellular energy transformation processes and neurochemical events that take place at the time of brain injury and shortly thereafter emphasizing hypoxia-ischemia, cerebrovascular accident, and traumatic brain injury. New interpretations of established concepts, such as diffuse axonal injury, are discussed; specific events, such as free radical production, excess production of excitatory amino acids, and disruption of calcium homeostasis, are reviewed. Neurochemically-based interventions are also presented: calcium channel blockers, excitatory amino acid antagonists, free radical scavengers, and hypothermia treatment. Concluding remarks focus on the role of clinical neuropsychologists in validation of treatment interventions.
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Affiliation(s)
- T A Novack
- Department of Rehabilitation Medicine, University of Alabama at Birmingham 35233-7330, USA
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Higuchi T, Fernandez EJ, Maudsley AA, Shimizu H, Weiner MW, Weinstein PR. Mapping of lactate and N-acetyl-L-aspartate predicts infarction during acute focal ischemia: in vivo 1H magnetic resonance spectroscopy in rats. Neurosurgery 1996; 38:121-9; discussion 129-30. [PMID: 8747960 DOI: 10.1097/00006123-199601000-00030] [Citation(s) in RCA: 51] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
The time course, anatomic distribution, and extent of changes in cerebral lactate, N-acetyl-L-aspartate (NAA), and other metabolite levels determined by three-dimensional in vivo 1H magnetic resonance spectroscopy and single-voxel spectral analysis after middle cerebral artery occlusion in rats. Increased lactate was detected in the central ischemic region within 1.3 hours after the onset of permanent occlusion (n = 22) or 0.5 hour after the onset of 1 hour of temporary occlusion and then reperfusion (n = 8). Permanent occlusion resulted in persistent lactate elevation and a 25.4 +/- 4.1% reduction in the NAA peak after 1.3 hours; NAA was almost completely depleted after 24 hours. Results also demonstrated delayed depletion of all other magnetic resonance spectroscopy-visible 1H metabolites, including creatine, choline, and glutamate, after permanent occlusion. After 1 hour of temporary focal ischemia, lactate returned to nearly normal levels within 0.4 hour after the onset of reperfusion; at 72 hours, a recurrent increase in lactate and a new decrease in NAA were observed, suggesting delayed tissue injury. Histological analysis, performed in 10 rats, demonstrated infarcts that corresponded in distribution to regions of NAA depletion at 72 hours. These findings indicate that lactate elevation is a sensitive early marker of ischemia; however, temporary recovery of lactate accumulation after reperfusion did not predict sustained metabolic recovery. In contrast, NAA depletion within 1.3 hours after the onset of ischemia identified central ischemic regions that were destined for infarction. Potential clinical applications include selection and monitoring of therapeutic intervention, as well as prediction of outcome, in patients with acute stroke.
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Affiliation(s)
- T Higuchi
- Magnetic Resonance Unit, Department of Veterans Affairs Medical Center, San Francisco, California, USA
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Felber SR, Ettl AR, Birbamer GG, Luz G, Aichner FT. MR imaging and proton spectroscopy of the brain in posttraumatic cortical blindness. J Magn Reson Imaging 1993; 3:921-4. [PMID: 8280984 DOI: 10.1002/jmri.1880030621] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Magnetic resonance (MR) imaging and localized proton MR spectroscopy of the occipital lobes were performed in a patient with cortical blindness following brain trauma. Computed tomography (CT) scans and MR images of the visual cortex were normal in the acute stage. Six weeks after the trauma, MR images showed cortical lesions in both occipital lobes, while the spectra showed elevated lactate and decreased N-acetyl aspartate levels relative to those of healthy volunteers. One year later, visual acuity had improved and follow-up studies revealed an increase in the ratios of N-acetyl aspartate to choline and creatine. These results demonstrate that parenchymal lesions may develop in brain regions that appear normal at CT and MR imaging during the acute stage after trauma. Metabolic changes can be observed in these areas by means of localized proton MR spectroscopy.
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Affiliation(s)
- S R Felber
- Department of Magnetic Resonance, University of Innsbruck, Austria
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Vink R. Nuclear magnetic resonance characterization of secondary mechanisms following traumatic brain injury. MOLECULAR AND CHEMICAL NEUROPATHOLOGY 1993; 18:279-97. [PMID: 8507306 DOI: 10.1007/bf03160120] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Much of the injury that occurs following a traumatic insult to the central nervous system is the result of physiological and biochemical processes initiated by the primary traumatic event. These processes occur over a period of hours to days following the insult, and although a number of factors have been identified as being associated with this secondary injury process, their role and interrelationship with one another is unclear. Nuclear magnetic resonance spectroscopy has been utilized to characterize many of these secondary factors and their relationship to eventual neurological outcome. In particular, the role of high energy phosphates, pH, lactic acid, excitatory amino acids, and magnesium has been investigated, along with pharmacotherapies directed toward altering the status of these factors following traumatic injury. This review critically examines the role that each of these factors may play in the secondary injury process, and proposes a scheme which theoretically accounts for the interrelationships among the various factors.
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Affiliation(s)
- R Vink
- Department of Chemistry and Biochemistry, James Cook University of North Queensland, Townsville, Australia
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Sonnewald U, Westergaard N, Schousboe A, Svendsen JS, Unsgård G, Petersen SB. Direct demonstration by [13C]NMR spectroscopy that glutamine from astrocytes is a precursor for GABA synthesis in neurons. Neurochem Int 1993; 22:19-29. [PMID: 8095170 DOI: 10.1016/0197-0186(93)90064-c] [Citation(s) in RCA: 190] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Primary cultures of cerebral cortical astrocytes and neurons, as well as neurons growing on top of the astrocytes (sandwich co-cultures), were incubated with 1-[13C]glucose or 2-[13C]acetate and in the presence or absence of the glutamine synthetase inhibitor methionine sulfoximine. [13C]NMR spectroscopy at 125 MHz was performed on perchloric acid extracts of the cells or on media collected from the cultures. In addition, the [13C/12C] ratios of the amino acids glutamine, glutamate and 4-aminobutyrate (GABA) were determined by gas chromatography/mass spectroscopy, showing a larger degree of labeling in GABA than in glutamate and glutamine from glucose. Glutamine and glutamate were predominantly labeled from acetate. A picture of cellular metabolism mainly regarding the tricarboxylic acid cycle and glycolysis was obtained. Due to the fact that acetate is not metabolized by neurons to any significant extent, it could be shown that precursors from astrocytes are incorporated into the GABA pool of neurons grown in co-culture with astrocytes. Spectra of media removed from these cultures revealed that likely precursor candidates for GABA were glutamine and citrate. The importance of glutamine is further substantiated by the finding that inhibition of glutamine synthetase, an enzyme present in astrocytes only, significantly decreased the labeling of GABA in co-cultures incubated with 2-[13C]acetate.
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Fernandez EJ, Maudsley AA, Higuchi T, Weiner MW. Three-dimensional 1H spectroscopic imaging of cerebral metabolites in the rat using surface coils. Magn Reson Imaging 1992; 10:965-74. [PMID: 1461094 DOI: 10.1016/0730-725x(92)90451-5] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Three dimensional metabolite maps of protonated metabolites were obtained using 1H magnetic resonance spectroscopic imaging at 7 T. Surface coils were used to increase sensitivity and spatial resolution significantly over a volume coil two-dimensional acquisition. Adiabatic pulses were employed to provide homogeneous B1 excitation and frequency selective refocusing over the volume of the rat brain. These techniques were employed to obtain three-dimensional spectroscopic imaging spectra from nominal voxel volumes of 9-30 microliters from rat brain. The improved spatial resolution and sensitivity are also demonstrated with studies of focal ischemia in the rat.
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Affiliation(s)
- E J Fernandez
- Department of Radiology, University of California, San Francisco
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Chang LH, Cohen Y, Weinstein PR, Chileuitt L, James TL. Interleaved 1H and 31P spectroscopic imaging for studying regional brain injury. Magn Reson Imaging 1991; 9:223-7. [PMID: 2034056 DOI: 10.1016/0730-725x(91)90014-d] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
We present a new approach for in vivo localized spectroscopy which combines 1H and 31P one-dimensional spectroscopic imaging pulse sequences in an interleaved, time-shared manner using a surface coil. This approach was used to acquire metabolic information from a rat brain with regional ischemia at 4.7 Tesla. Spectra with very good signal-to-noise ratios, void of chemical shift artifacts, are obtainable from voxel sizes less than 0.3 cm3 in 40 min. Advantages and drawbacks of the proposed methodology are discussed.
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Affiliation(s)
- L H Chang
- Department of Pharmaceutical Chemistry, University of California, San Francisco 94143
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