Comparison of diffusion‐ and T2‐weighted MRI for the early detection of cerebral ischemia and reperfusion in rats

Mintorovitch, Jan; Moseley, Michael E.; Chileuitt, L.; Shimizu, Hiroaki; Cohen, Yoram; Weinstein, Philip

doi:10.1002/mrm.1910180106

Cited by 470 publications

(224 citation statements)

References 21 publications

(14 reference statements)

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“…A reduced water apparent diffusion coefficient (ADC) has also been reported in other pathological states, such as stroke (38,39). Diffusion MRI is the gold standard neuroimaging method to diagnose occlusive stroke clinically, reliably producing an increased diffusion-weighted signal and a concomitant reduction in the ADC in ischemic areas (40,41).…”

Section: Diffusion Mr In a Pathological Stroke Model Via Oxygen/glucosementioning

confidence: 93%

Assessing the sensitivity of diffusion MRI to detect neuronal activity directly

Bai

Stewart

Plenz

et al. 2016

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

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Functional MRI (fMRI) is widely used to study brain function in the neurosciences. Unfortunately, conventional fMRI only indirectly assesses neuronal activity via hemodynamic coupling. Diffusion fMRI was proposed as a more direct and accurate fMRI method to detect neuronal activity, yet confirmative findings have proven difficult to obtain. Given that the underlying relation between tissue water diffusion changes and neuronal activity remains unclear, the rationale for using diffusion MRI to monitor neuronal activity has yet to be clearly established. Here, we studied the correlation between water diffusion and neuronal activity in vitro by simultaneous calcium fluorescence imaging and diffusion MR acquisition. We used organotypic cortical cultures from rat brains as a biological model system, in which spontaneous neuronal activity robustly emerges free of hemodynamic and other artifacts. Simultaneous fluorescent calcium images of neuronal activity are then directly correlated with diffusion MR signals now free of confounds typically encountered in vivo. Although a simultaneous increase of diffusion-weighted MR signals was observed together with the prolonged depolarization of neurons induced by pharmacological manipulations (in which cell swelling was demonstrated to play an important role), no evidence was found that diffusion MR signals directly correlate with normal spontaneous neuronal activity. These results suggest that, whereas current diffusion MR methods could monitor pathological conditions such as hyperexcitability, e.g., those seen in epilepsy, they do not appear to be sensitive or specific enough to detect or follow normal neuronal activity.D eveloping a direct MRI method to detect neuronal activity in vivo and noninvasively is a major focus in neuroscience. Progress in this area is required to improve our understanding of normal brain function, and in a clinical setting, to develop new tools for studying normal and abnormal development to diagnose diseases and disorders of the brain. Functional MRI (fMRI) has been widely used in the cognitive neurosciences since its invention in the 1990s (1-3). The most widely used fMRI method, blood-oxygenation-level-dependent (BOLD) MRI, detects hemodynamic changes in the brain, which only indirectly reflects neuronal activity. Moreover, its hemodynamic origin limits both its spatial and temporal resolution and its interpretation as a direct proxy for neuronal activity (4, 5).More recently, several MRI methods were proposed to provide more direct measures of neuronal excitation (6). In particular, diffusion MRI, a method to measure the apparent diffusivity of water within tissues (7-9), has been suggested as a direct functional imaging method to detect neuronal activity (10-13). Early in vivo experiments in both humans and animals reported small but significant increases in highly diffusion-weighted MRI signals, which were ascribed to changes directly induced by the underlying neuronal activity rather than indirect hemodynamic changes (10-13).In vitro experimen...

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Section: Diffusion Mr In a Pathological Stroke Model Via Oxygen/glucosementioning

confidence: 93%

Assessing the sensitivity of diffusion MRI to detect neuronal activity directly

Bai

Stewart

Plenz

et al. 2016

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

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“…Reversal of ischemia sufficiently early causes reversal of the ADC changes that is not greater than a threshold value and prevents infarction. 30 Apparent diffusion coefficient does not decrease until oxygen delivery decreases below levels critical for maintenance of Na þ -K þ ATPase activity. 31 Reversible decreases in ADC are seen in the tissues immediately surrounding an infarct (the penumbra) 23 and these represent areas of brain in which there is temporary interruption of Na þ -K þ ATPase, but not sufficient to cause Na þ -K þ ATPase failure and disrupted ionic homeostasis.…”

Section: Diffusion-weighted Mri Changes In Acute Mountain Sickness Jsmentioning

confidence: 99%

Cerebral Diffusion and T₂: MRI Predictors of Acute Mountain Sickness during Sustained High-Altitude Hypoxia

Hunt

Theilmann

Smith

et al. 2012

J Cereb Blood Flow Metab

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Diffusion magnetic resonance imaging (MRI) provides a sensitive indicator of cerebral hypoxia. We investigated if apparent diffusion coefficient (ADC) and transverse relaxation (T 2 ) predict symptoms of acute mountain sickness (AMS), or merely indicate the AMS phenotype irrespective of symptoms. Fourteen normal subjects were studied in two groups; unambiguous AMS and no-AMS at 3,800 m altitude (intermediate AMS scores were excluded). T 2 relaxation was estimated from a T 2 index of T 2 -weighted signal normalized by cerebrospinal fluid signal. Measurements were made in normoxia and repeated after 2 days sustained hypoxia (AMS group symptomatic and no-AMS group asymptomatic) and after 7 days hypoxia (both groups asymptomatic). Decreased ADC directly predicted AMS symptoms (Po0.05). Apparent diffusion coefficient increased in asymptomatic subjects, or as symptoms abated with acclimatization. This pattern was similar in basal ganglia, white matter, and gray matter. Corpus callosum behaved differently; restricted diffusion was absent (or rapidly reversed) in the splenium, and was sustained in the genu. In symptomatic subjects, T 2,index decreased after 2 days hypoxia and further decreased after 7 days. In asymptomatic subjects, T 2,index initially increased after 2 days, but decreased after 7 days. T 2,index changes were not predictive of AMS symptoms. These findings indicate that restricted diffusion, an indicator of diminished cerebral energy status, directly predicts symptoms of AMS in humans at altitude.

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“…The Diffusion-weighted magnetic resonance imaging (DWI) is derived by measuring the translational movement (diffusion) of water molecules over a short interval (Le Bihan et al, 1986;. DWI can rapidly detect and localize focal brain injury as early as minutes after the onset of ischemia (Moseley et al, 1990a,b;Mintorovitch et al, 1991;Minematsu et al, 1992a,b). This method is a powerful tool for studying clinical and experi mental brain ischemia.…”

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confidence: 99%

Temperature Dependent Change of Apparent Diffusion Coefficient of Water in Normal and Ischemic Brain of Rats

Hasegawa

Latour

Sotak

et al. 1994

J Cereb Blood Flow Metab

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Summary: To identify the temperature dependent change of the apparent diffusion coefficient (ADC) of water in brain tissue, the ADC values of normal rat brain were measured over a range of body temperatures with moni toring of head temperature using a small water reference implanted under the temporalis muscle. An initial exper iment using thermocouples implanted into the cortex, caudate-putamen, temporalis muscle, and rectum demon strated that temperature in all regions were highly corre lated over a temperature range from 33 to 39°C. In an other group of normal rats, brain ADC values varied al most uniformly with body temperature over the temperature range 33-39°C, implying that brain ADC val ues accurately reflect changes in brain temperature. The Diffusion-weighted magnetic resonance imaging (DWI) is derived by measuring the translational movement (diffusion) of water molecules over a short interval (Le Bihan et al., 1986;. DWI can rapidly detect and localize focal brain injury as early as minutes after the onset of ischemia (Moseley et al., 1990a,b;Mintorovitch et al., 1991; Minematsu et al., 1992a,b). This method is a powerful tool for studying clinical and experi mental brain ischemia.Brain temperature is an important physiologic pa rameter that should be monitored during experi- Abbreviations used: ADC, apparent diffusion coefficient; CCA, common carotid artery; DWI, diffusion-weighted imaging; MCA, middle cerebral artery; MRI, magnetic resonance imag ing; NMDA, N-methyl-o-aspartate; ROI, region of interest. 383effects of focal ischemia and administration of the non competitive N-methyl-o-aspartate (NMDA) antagonist, CNS-1102, on ADC were also examined, using the suture middle cerebral artery (MCA) occlusion model while maintaining the body temperature at 37°C. ADC values and therefore brain temperature in the nonischemic and ischemic hemispheres were not affected by the drug. These experiments suggest that brain ADC measurement could be useful in animal studies and, potentially, in hu mans to assess the effects of pharmacologic intervention on brain temperature. Key Words: Middle cerebral artery occlusion-Brain temperature-Magnetic resonance im aging-Apparent diffusion coefficient-Diffusion map ping.

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Comparison of diffusion‐ and T2‐weighted MRI for the early detection of cerebral ischemia and reperfusion in rats

Cited by 470 publications

References 21 publications

Assessing the sensitivity of diffusion MRI to detect neuronal activity directly

Assessing the sensitivity of diffusion MRI to detect neuronal activity directly

Cerebral Diffusion and T₂: MRI Predictors of Acute Mountain Sickness during Sustained High-Altitude Hypoxia

Temperature Dependent Change of Apparent Diffusion Coefficient of Water in Normal and Ischemic Brain of Rats

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Comparison of diffusion‐ and T2‐weighted MRI for the early detection of cerebral ischemia and reperfusion in rats

Cited by 470 publications

References 21 publications

Assessing the sensitivity of diffusion MRI to detect neuronal activity directly

Assessing the sensitivity of diffusion MRI to detect neuronal activity directly

Cerebral Diffusion and T2: MRI Predictors of Acute Mountain Sickness during Sustained High-Altitude Hypoxia

Temperature Dependent Change of Apparent Diffusion Coefficient of Water in Normal and Ischemic Brain of Rats

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Cerebral Diffusion and T₂: MRI Predictors of Acute Mountain Sickness during Sustained High-Altitude Hypoxia