Cranial anatomy and detection of ischemic stroke in the cat by nuclear magnetic resonance imaging.

Buonanno, Ferdinando S.; Pykett, I L; Kistler, J P; Vielma, J; Brady, Thomas J.; Hinshaw, W. S.; Goldman, M.; Newhouse, J H; Pohost, Gerald M.

doi:10.1148/radiology.143.1.7063725

Cited by 42 publications

(3 citation statements)

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“…Proton density, T 1 -weighted (T 1 W), and T 2 -weighted (T 2 W) MRI are considered as conventional MRI methods in the assessment of neurologic disorders. During the starting years of biomedical applications of MRI, these techniques demonstrated their potential to detect cerebral lesions in animal models of stroke (Buonanno et al, 1982), traumatic brain injury (Bederson et al, 1986), brain tumors (Bederson et al, 1986), and multiple sclerosis (Stewart et al, 1985). An increase in proton density, as well as T 1 and T 2 , in pathologic tissue is attributed to an increase in interstitial water associated with the development of vasogenic edema (see van Bruggen et al, 1994 and references therein) ( Fig.…”

Section: Proton Density and T 1 -And T 2 -Weighted Magnetic Resonancementioning

confidence: 99%

Magnetic Resonance Imaging in Experimental Models of Brain Disorders

Dijkhuizen

Nicolay

2003

J Cereb Blood Flow Metab

126

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Summary:This review gives an overview of the application of magnetic resonance imaging (MRI) in experimental models of brain disorders. MRI is a noninvasive and versatile imaging modality that allows longitudinal and three-dimensional assessment of tissue morphology, metabolism, physiology, and function. MRI can be sensitized to proton density, T 1 , T 2 , susceptibility contrast, magnetization transfer, diffusion, perfusion, and flow. The combination of different MRI approaches (e.g., diffusion-weighted MRI, perfusion MRI, functional MRI, cellspecific MRI, and molecular MRI) allows in vivo multiparametric assessment of the pathophysiology, recovery mechanisms, and treatment strategies in experimental models of stroke, brain tumors, multiple sclerosis, neurodegenerative diseases, traumatic brain injury, epilepsy, and other brain disorders. This report reviews established MRI methods as well as promising developments in MRI research that have advanced and continue to improve our understanding of neurologic diseases and that are believed to contribute to the development of recovery improving strategies.

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Section: Proton Density and T 1 -And T 2 -Weighted Magnetic Resonancementioning

confidence: 99%

Magnetic Resonance Imaging in Experimental Models of Brain Disorders

Dijkhuizen

Nicolay

2003

J Cereb Blood Flow Metab

126

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“…The reduction in the water diffusion coefficient is now widely used in delineation of ischemic tissue by MRI, yet the biophysical mechanisms underlying the diffusion change are only partially understood. Several reports have shown that magnetic resonance (MR) contrast from prolongation of either T 1 or T 2 relaxation of tissue water protons develops only after several hours of ischemia and is an index of irreversible water accumulation (Buonanno et al, 1982; Kato et al, 1985; Knight et al, 1994). Based on the known temporal patterns, diffusion and T 2 MRI have been exploited for monitoring the evolution of ischemic tissue damage (Welch et al, 1995).…”

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confidence: 99%

Quantitative T_1ρ and Magnetization Transfer Magnetic Resonance Imaging of Acute Cerebral Ischemia in the Rat

Mäkelä¹,

Kettunen²,

Gröhn³

et al. 2002

J Cereb Blood Flow Metab

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It has been previously shown that T1 in the rotating frame (T(1rho)) is a very sensitive and early marker of cerebral ischemia and that, interestingly, it can provide prognostic information about the degree of subsequent neuronal damage. In the present study the authors have quantified T(1rho) together with the rate and other variables of magnetization transfer (MT) associated with spin interactions between the bulk and semisolid macromolecular pools by means of Z spectroscopy, to examine the possible overlap of mechanisms affecting these magnetic resonance imaging contrasts. Substantial prolongation of cerebral T(1rho) was observed minutes after induction of ischemia, this change progressing in a time-dependent manner. Difference Z spectra (contralateral nonischemic minus ischemic brain tissue) showed a significant positive reminder in the time points from 0.5 to 3 hours after induction of ischemia, the polarity of this change reversing by 24 hours. Detailed analysis of the MT variables showed that the initial Z spectral changes were due to concerted increase in the maximal MT (+3%) and amount of MT (+4%). Interestingly, the MT rates derived either from the entire frequency range of Z spectra or the time constant for the first-order forward exchange (k(sat)) were unchanged at this time, these variables reducing only one day after induction of ischemia. The authors conclude that T(1rho) changes in the acute phase of ischemia coincide with both elevated maximal MT and amount of MT. These changes occur independent of the overall MT rate and in the absence of net water gain to the tissue, whereas in the consolidating infarction the decrease in the rate and amount of MT, as well as the extensive prolongation of T(1rho), are associated with water accumulation.

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“…Such time resolution would allow correlations between lactate production and clearance in vivo with other variables that can be measured noninvasively. These include intracellular pH and the state of phosphate energy stores obtained from 31P NMR experiments (6,25), the functional state of the brain as reflected in the electroencephalogram, and possibly cerebral blood flow (26). These prospects are particularly interesting in light of the probable role of high lactate concen- (Spectrum E) After 41 min at 25% 02.…”

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confidence: 99%

High-resolution 1H nuclear magnetic resonance study of cerebral hypoxia in vivo.

Behar¹,

Hollander²,

Stromski³

et al. 1983

Proc. Natl. Acad. Sci. U.S.A.

267

129

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1H NMR spectra at 360.13 MHz were obtained of the rat brain in vivo by using a surface coil placed over the skull. Resonances of numerous metabolites were identified by comparison with the 1H NMR spectra of excised rat brain tissue and acid extracts of the tissue. Changes in cerebral lactate levels resulting from the administration of gas mixtures low in oxygen were monitored in the in vivo brain spectra with a time resolution of 2.3 min. The electroencephalogram and electrocardiogram were recorded simultaneously during the NMR experiment. Reversibility of the hypoxic response was documented when, upon oxygen administration, cerebral lactate returned to its prehypoxic level. These experiments demonstrate the applicability of high-resolution 1H NMR to monitor pathophysiology of brain metabolism in real time.Nuclear magnetic resonance spectroscopy (NMR) is rapidly developing into a major tool for the study of metabolism in vivo. Both 31p and 13C NMR have been used extensively in metabolic studies of cellular suspensions and perfused organs (1, 2). The recent introduction of surface coils (3) has led to the successful application of topical 31P NMR to studies of the vital organs of animals and man (4-6). Recently, topical 13C NMR has been shown to be capable of monitoring glycogen stores and acyl glycerides in vivo (7-9), greatly extending the kinds of metabolic information that can be obtained. MATERIALS AND METHODS Animal Preparation for in Vivo 1H Experiments. Rats of theCharles River strain (220-240 g), fed ad lib, were anesthetized with halothane (1%), tracheotomized, mechanically ventilated (25% 02/75% N20), and paralyzed with D-tubocurarine chloride (1.5 mg/kg, subcutaneously) and pancuronium bromide (1 mg/kg, subcutaneously). The animals were equipped with electrocardiogram leads on the left extremities and scalp leads for electroencephalogram recording. An incision was made along the midline of the calvarium so that skin and temporalis muscles-detached from the temporal ridge-could be retracted and fixed in position away from the skull. The rat was mounted vertically in a Plexiglass retainer and a small surface coil was centered 6 mm occipital to the bregma. These precautions ensure that only the contents of the skull are observed.Extract Preparation for 1H NMR. Extracts were prepared from rat brain frozen in situ (18) in the following manner: frozen cortical tissue was chipped away (68 mg) and extracted with 99% MeOH/0. 1 M HCl (2:1, wt/vol) and 0.1 M perchloric acid (10:1, wt/vol) according to well-established methods (19) with minor modifications. In the extraction procedure, 0.1 M sodium phosphate (pH 7.2) was substituted for imidazole buffer (19). After neutralization with 1.5 M KOH/0.3 M KCI the sample was lyophilized and dissolved in 0.38 ml of a 0.1 M phosphate/2H20 buffer (pH 7.2) and placed in a 5-mm NMR tube for analysis.Chemical shifts for resonances in excised and in vivo brain tissue were referenced to N-acetylaspartate at 2.023 ppm relative to sodium 3-trimethylsilyl[2,2,3,3-2H]pro...

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Cranial anatomy and detection of ischemic stroke in the cat by nuclear magnetic resonance imaging.

Cited by 42 publications

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Magnetic Resonance Imaging in Experimental Models of Brain Disorders

Magnetic Resonance Imaging in Experimental Models of Brain Disorders

Quantitative T_1ρ and Magnetization Transfer Magnetic Resonance Imaging of Acute Cerebral Ischemia in the Rat

High-resolution 1H nuclear magnetic resonance study of cerebral hypoxia in vivo.

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Cranial anatomy and detection of ischemic stroke in the cat by nuclear magnetic resonance imaging.

Cited by 42 publications

References 0 publications

Magnetic Resonance Imaging in Experimental Models of Brain Disorders

Magnetic Resonance Imaging in Experimental Models of Brain Disorders

Quantitative T1ρ and Magnetization Transfer Magnetic Resonance Imaging of Acute Cerebral Ischemia in the Rat

High-resolution 1H nuclear magnetic resonance study of cerebral hypoxia in vivo.

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Quantitative T_1ρ and Magnetization Transfer Magnetic Resonance Imaging of Acute Cerebral Ischemia in the Rat