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1.
Sci Rep ; 14(1): 8316, 2024 04 09.
Artigo em Inglês | MEDLINE | ID: mdl-38594386

RESUMO

Animal models of brain function are critical for the study of human diseases and development of effective interventions. Resting-state network (RSN) analysis is a powerful tool for evaluating brain function and performing comparisons across animal species. Several studies have reported RSNs in the common marmoset (Callithrix jacchus; marmoset), a non-human primate. However, it is necessary to identify RSNs and evaluate commonality and inter-individual variance through analyses using a larger amount of data. In this study, we present marmoset RSNs detected using > 100,000 time-course image volumes of resting-state functional magnetic resonance imaging data with careful preprocessing. In addition, we extracted brain regions involved in the composition of these RSNs to understand the differences between humans and marmosets. We detected 16 RSNs in major marmosets, three of which were novel networks that have not been previously reported in marmosets. Since these RSNs possess the potential for use in the functional evaluation of neurodegenerative diseases, the data in this study will significantly contribute to the understanding of the functional effects of neurodegenerative diseases.


Assuntos
Callithrix , Doenças Neurodegenerativas , Animais , Humanos , Imageamento por Ressonância Magnética/métodos , Encéfalo/diagnóstico por imagem , Mapeamento Encefálico/métodos
2.
Neurosci Res ; 2024 Apr 16.
Artigo em Inglês | MEDLINE | ID: mdl-38636670

RESUMO

The field of aging biology, which aims to extend healthy lifespans and prevent age-related diseases, has turned its focus to the Callithrix jacchus (common marmoset) to understand the aging process better. This study utilized magnetic resonance imaging (MRI) to non-invasively analyze the brains of 216 marmosets, investigating age-related changes in brain structure; the relationship between body weight and brain volume; and potential differences between males and females. The key findings revealed that, similar to humans, Callithrix jacchus experiences a reduction in total intracranial volume, cortex, subcortex, thalamus, and cingulate volumes as they age, highlighting site-dependent changes in brain tissue. Notably, the study also uncovered sex differences in cerebellar volume. These insights into the structural connectivity and volumetric changes in the marmoset brain throughout aging contribute to accumulating valuable knowledge in the field, promising to inform future aging research and interventions for enhancing healthspan.

3.
Heliyon ; 10(4): e26391, 2024 Feb 29.
Artigo em Inglês | MEDLINE | ID: mdl-38434080

RESUMO

In diffusion magnetic resonance imaging, oscillating gradient spin echo (OGSE) has an extremely short diffusion time if motion probing gradient (MPG) is applied to the waveform. Further, it can detect microstructural specificity. OGSE changes sensitivity to spin displacement velocity based on the MPG phase. The current study aimed to investigate the restricted diffusion characteristics of each OGSE waveform using the capillary phantom with various b-values, frequencies, and MPG phases. We performed OGSE (b-value = 300, 500, 800, 1200, 1600, and 2000 s/mm2) for the sine and cosine waveforms using the capillary phantom (6, 12, 25, 50, and 100 µm and free water) with a 9.4-T experimental magnetic resonance imaging system and a solenoid coil. We evaluated the axial and radial diffusivity (AD, RD) of each structure size. The output current of the MPG was assessed with an oscilloscope and analyzed with the gradient modulation power spectra by fast Fourier transform. In sine, the sidelobe spectrum was enhanced with increasing frequency, and the central spectrum slightly increased. The difference in RD was detected at 6 and 12 µm; however, it did not depend on the structure scale at 50 or 100 µm and free water. In cosine, the diffusion spectrum was enhanced, whereas the central spectrum decreased with increasing frequency. Both AD and RD in cosine had a frequency dependence, and AD and RD increased with a higher frequency regardless of structure size. AD and RD in either sine or cosine had no evident b-value dependence. We evaluated the OGSE-restricted diffusion characteristics. The measurements obtained diffusion information similar to the pulsed gradient spin echo. Hence, the cosine measurements indicated that a higher frequency could capture faster diffusion within the diffusion phenomena.

4.
Front Neurosci ; 18: 1337976, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38516310

RESUMO

The N-back task is widely used to investigate working memory. Previous functional magnetic resonance imaging (fMRI) studies have shown that local brain activation depends on the difficulty of the N-back task. Recently, changes in functional connectivity and local activation during a task, such as a single-hand movement task, have been reported to give the distinct information. However, previous studies have not investigated functional connectivity changes in the entire brain during N-back tasks. In this study, we compared alterations in functional connectivity and local activation related to the difficulty of the N-back task. Because structural connectivity has been reported to be associated with local activation, we also investigated the relationship between structural connectivity and accuracy in a N-back task using diffusion tensor imaging (DTI). Changes in functional connectivity depend on the difficulty of the N-back task in a manner different from local activation, and the 2-back task is the best method for investigating working memory. This indicates that local activation and functional connectivity reflect different neuronal events during the N-back task. The top 10 structural connectivities associated with accuracy in the 2-back task were locally activated during the 2-back task. Therefore, structural connectivity as well as fMRI will be useful for predicting the accuracy of the 2-back task.

5.
PLoS One ; 19(2): e0297273, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38300967

RESUMO

Currently, we can label the certain cells by transducing specific genes, called reporter genes, and distinguish them from other cells. For example, fluorescent protein such as green fluorescence protein (GFP) is commonly used for cell labeling. However, fluorescent protein is difficult to observe in living animals. We can observe the reporter signals of the luciferin-luciferase system from the outside of living animals using in vivo imaging systems, although the resolution of this system is low. Therefore, in this study, we examined the reporter genes, which allowed the MRI-mediated observation of labeled cells in living animals. As a preliminary stage of animal study, we transduced some groups of plasmids that coded the protein that could take and store metal ions to the cell culture, added metal ions solutions, and measured their T1 or T2 relaxation values. Finally, we specified the best reporter gene combination for MRI, which was the combination of transferrin receptor, DMT1, and Ferritin-M6A for T1WI, and Ferritin-M6A for T2WI.


Assuntos
Ferritinas , Imageamento por Ressonância Magnética , Animais , Genes Reporter , Ferritinas/genética , Linhagem Celular Tumoral , Proteínas de Fluorescência Verde/genética , Proteínas de Fluorescência Verde/metabolismo , Imageamento por Ressonância Magnética/métodos , Íons/metabolismo
6.
Magn Reson Med Sci ; 23(2): 136-145, 2024 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-36754420

RESUMO

PURPOSE: Diffusion MRI is a physical measurement method that quantitatively indicates the displacement of water molecules diffusing in voxels. However, there are insufficient data to characterize the diffusion process physically in a uniform structure such as a phantom. This study investigated the transitional relationship between structure scale, temperature, and diffusion time for simple restricted diffusion using a capillary phantom. METHODS: We performed diffusion-weighted pulsed-gradient stimulated-echo acquisition mode (STEAM) MRI with a 9.4 Tesla MRI system (Bruker BioSpin, Ettlingen, Germany) and a quadrature coil with an inner diameter of 86 mm (Bruker BioSpin). We measured the diffusion coefficients (radial diffusivity [RD]) of capillary plates (pore sizes 6, 12, 25, 50, and 100 µm) with uniformly restricted structures at various temperatures (10ºC, 20ºC, 30ºC, and 40ºC) and multiple diffusion times (12-800 ms). We evaluated the characteristics of scale, temperature, and diffusion time for restricted diffusion. RESULTS: The RD decayed and became constant depending on the structural scale. Diffusion coefficient fluctuations with temperature occurred mostly under conditions of a large structural scale and short diffusion time. We obtained data suggesting that temperature-dependent changes in the diffusion coefficients follow physical laws. CONCLUSION: No water molecules were observed outside the glass tubes in the capillary plates, and the capillary plates only reflected a restricted diffusion process within the structure.We experimentally evaluated the characteristics of simple restricted diffusion to reveal the transitional relationship of the diffusion coefficient with diffusion time, structure scale, and temperature through composite measurement.


Assuntos
Imagem de Difusão por Ressonância Magnética , Imageamento por Ressonância Magnética , Temperatura , Imagem de Difusão por Ressonância Magnética/métodos , Difusão , Transporte Biológico , Imagens de Fantasmas , Água
7.
Cell Rep Med ; 4(10): 101208, 2023 10 17.
Artigo em Inglês | MEDLINE | ID: mdl-37774703

RESUMO

Dyskinesia is involuntary movement caused by long-term medication with dopamine-related agents: the dopamine agonist 3,4-dihydroxy-L-phenylalanine (L-DOPA) to treat Parkinson's disease (L-DOPA-induced dyskinesia [LID]) or dopamine antagonists to treat schizophrenia (tardive dyskinesia [TD]). However, it remains unknown why distinct types of medications for distinct neuropsychiatric disorders induce similar involuntary movements. Here, we search for a shared structural footprint using magnetic resonance imaging-based macroscopic screening and super-resolution microscopy-based microscopic identification. We identify the enlarged axon terminals of striatal medium spiny neurons in LID and TD model mice. Striatal overexpression of the vesicular gamma-aminobutyric acid transporter (VGAT) is necessary and sufficient for modeling these structural changes; VGAT levels gate the functional and behavioral alterations in dyskinesia models. Our findings indicate that lowered type 2 dopamine receptor signaling with repetitive dopamine fluctuations is a common cause of VGAT overexpression and late-onset dyskinesia formation and that reducing dopamine fluctuation rescues dyskinesia pathology via VGAT downregulation.


Assuntos
Discinesia Induzida por Medicamentos , Transtornos Parkinsonianos , Camundongos , Animais , Agonistas de Dopamina/efeitos adversos , Levodopa/efeitos adversos , Dopamina , Antiparkinsonianos/efeitos adversos , Transtornos Parkinsonianos/induzido quimicamente , Transtornos Parkinsonianos/patologia , Discinesia Induzida por Medicamentos/etiologia , Discinesia Induzida por Medicamentos/tratamento farmacológico , Discinesia Induzida por Medicamentos/patologia , Oxidopamina/efeitos adversos , Ácido gama-Aminobutírico/efeitos adversos
8.
J Neurol ; 270(12): 5924-5934, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-37626243

RESUMO

BACKGROUND: Orthostatic hypotension (OH) is a potential modifiable risk factor for cognitive impairment in patients with Parkinson's disease (PD). Although other risk factors for dementia, hyposmia and REM sleep behavior disorder (RBD), are closely associated with autonomic dysfunction in PD, little is known about how these risk factors influence cognitive function and cerebral pathology. OBJECTIVE: We investigated how these three factors contribute to gray matter atrophy by considering the interaction of OH with hyposmia and RBD. METHODS: We analyzed cortical thickness, subcortical gray matter volume, and cognitive measures from 78 patients with de novo PD who underwent the head-up tilt test for the diagnosis of OH. RESULTS: Whole-brain analyses with Monte Carlo corrections revealed that hyposmia was associated with decreased cortical thickness in a marginal branch of the cingulate sulcus among patients with OH, and cortical thickness in this area correlated with cognitive functioning only in patients with OH. Subcortical gray matter volume analysis indicated that severe RBD was associated with decreased volume in the left hippocampus and bilateral amygdala among patients with OH. CONCLUSION: Even in early PD, OH exerts effects on gray matter atrophy and cognitive dysfunction by interacting with RBD and hyposmia. OH might exacerbate cerebral pathology induced by hyposmia or RBD.


Assuntos
Hipotensão Ortostática , Doença de Parkinson , Transtorno do Comportamento do Sono REM , Humanos , Transtorno do Comportamento do Sono REM/complicações , Doença de Parkinson/complicações , Doença de Parkinson/diagnóstico por imagem , Doença de Parkinson/patologia , Substância Cinzenta/patologia , Anosmia/complicações , Anosmia/patologia , Hipotensão Ortostática/complicações , Hipotensão Ortostática/diagnóstico por imagem , Atrofia/patologia
9.
Sci Data ; 10(1): 221, 2023 04 27.
Artigo em Inglês | MEDLINE | ID: mdl-37105968

RESUMO

Magnetic resonance imaging (MRI) is a non-invasive neuroimaging technique that is useful for identifying normal developmental and aging processes and for data sharing. Marmosets have a relatively shorter life expectancy than other primates, including humans, because they grow and age faster. Therefore, the common marmoset model is effective in aging research. The current study investigated the aging process of the marmoset brain and provided an open MRI database of marmosets across a wide age range. The Brain/MINDS Marmoset Brain MRI Dataset contains brain MRI information from 216 marmosets ranging in age from 1 and 10 years. At the time of its release, it is the largest public dataset in the world. It also includes multi-contrast MRI images. In addition, 91 of 216 animals have corresponding high-resolution ex vivo MRI datasets. Our MRI database, available at the Brain/MINDS Data Portal, might help to understand the effects of various factors, such as age, sex, body size, and fixation, on the brain. It can also contribute to and accelerate brain science studies worldwide.


Assuntos
Encéfalo , Callithrix , Imageamento por Ressonância Magnética , Animais , Encéfalo/diagnóstico por imagem , Bases de Dados Factuais , Imageamento por Ressonância Magnética/métodos , Neuroimagem/métodos , Fatores Etários
10.
Magn Reson Imaging ; 99: 1-6, 2023 06.
Artigo em Inglês | MEDLINE | ID: mdl-36608908

RESUMO

OBJECTIVE: Brain temperature monitoring using a catheter thermometer has been reported to be a useful technique to predict prognosis in neurosurgery. To investigate the possibility of measuring intracranial cerebrospinal fluid temperature for postoperative monitoring in patients with Moyamoya disease (MMD) after bypass surgery. MATERIALS AND METHODS: This study evaluated fifteen patients with MMD who were indicated for bypass surgery. Diffusion tensor imaging for brain thermometry were performed on a 1.5-T MR scanner. Intracranial cerebrospinal fluid temperature with/without considering the fractional anisotropy component, body temperature, C-reactive protein levels, white blood cell count, and cerebral blood flow measured by 123I-IMP single-photon emission computed tomography were obtained before surgery and 1-3 days after surgery. Pixel values considered to be signal outliers in fractional anisotropy processing were defined as cerebrospinal fluid noise index and calculated. Wilcoxon signed-rank test and effect size were performed to compare the changes before and after revascularization. Spearman's rho correlation coefficient was used to analyze the correlations between each parameter. Statistical significance was defined as p < 0.05. RESULTS: All parameter values became significantly higher compared to those measured before revascularization (p < 0.01 in all cases). The effect sizes were largest for the cerebrospinal fluid temperature with fractional anisotropy processing and for C-reactive protein levels (Rank-biserial correlation = 1.0). The cerebrospinal fluid noise index and cerebrospinal fluid temperatures with fractional anisotropy processing (r = 0.84, p < 0.0001) or without fractional anisotropy processing (r = 0.95, p < 0.0001) showed highly significant positive correlations. Although no significant correlation was observed, cerebrospinal fluid temperatures with fractional anisotropy had small or moderately positive correlations with cerebral blood flow, body temperature, C-reactive protein levels, and white blood cell count (r = 0.37, 0.42, 0.41, and 0.44, respectively; p > 0.05). CONCLUSION: Our findings suggest the possibility of postoperative monitoring for MMD patients by measuring intracranial cerebrospinal fluid temperature with fractional anisotropy processing. Intracranial cerebrospinal fluid temperature might be considered as combined response since cerebrospinal fluid, body temperature, and inflammation are equally correlated.


Assuntos
Imagem de Tensor de Difusão , Doença de Moyamoya , Humanos , Imagem de Tensor de Difusão/métodos , Temperatura , Temperatura Corporal , Proteína C-Reativa , Anisotropia
11.
Cereb Cortex ; 33(9): 5148-5162, 2023 04 25.
Artigo em Inglês | MEDLINE | ID: mdl-36222604

RESUMO

Common marmosets are promising laboratory animals for the study of higher brain functions. Although there are many opportunities to use sedatives and anesthetics in resting brain function measurements in marmosets, their effects on the resting-state network remain unclear. In this study, the effects of sedatives or anesthetics such as midazolam, dexmedetomidine, co-administration of isoflurane and dexmedetomidine, propofol, alfaxalone, isoflurane, and sevoflurane on the resting brain function in common marmosets were evaluated using independent component analysis, dual regression analysis, and graph-theoretic analysis; and the sedatives or anesthetics suitable for the evaluation of resting brain function were investigated. The results show that network preservation tendency under light sedative with midazolam and dexmedetomidine is similar regardless of the type of target receptor. Moreover, alfaxalone, isoflurane, and sevoflurane have similar effects on resting state brain function, but only propofol exhibits different tendencies, as resting brain function is more preserved than it is following the administration of the other anesthetics. Co-administration of isoflurane and dexmedetomidine shows middle effect between sedatives and anesthetics.


Assuntos
Anestésicos , Dexmedetomidina , Isoflurano , Propofol , Animais , Hipnóticos e Sedativos/farmacologia , Callithrix , Isoflurano/farmacologia , Sevoflurano/farmacologia , Midazolam/farmacologia , Dexmedetomidina/farmacologia , Anestésicos/farmacologia , Encéfalo
12.
J Comput Assist Tomogr ; 47(1): 121-128, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-36112043

RESUMO

OBJECTIVE: The aim of the study was to evaluate the relationship of amide proton transfer (APT) signal characteristics in brain tumors and uninvolved brain tissue for patients with glioblastoma and those with brain metastases. METHODS: Using the mDIXON 3D-APT sequence of the fast spin echo method, an APT image was obtained. The mean APT signal values of tumor core, peritumor edema, ipsilateral normal-appearing white matter (INAWM), and contralateral normal white matter (CNAWM) were obtained and compared between glioblastoma and brain metastases. Receiver operating characteristic curves were used to evaluate parameters for distinguishing between glioblastoma and brain metastases. In addition, the difference and change rate in APT signal values between tumor core and peritumoral edema (PE) and CNAWM were evaluated, respectively. RESULTS: The APT signal values of glioblastoma were the highest in tumor core (3.41% ± 0.49%), followed by PE (2.24% ± 0.29%), INAWM (1.35% ± 0.15%), and CNAWM (1.26% ± 0.12%, P < 0.001). The APT signal value of brain metastases was the highest in tumor core (2.74% ± 0.34%), followed by PE (1.86% ± 0.35%), INAWM (1.17% ± 0.13%), and CNAWM (1.2% ± 0.09%, P < 0.01). The APT change rate (between PE and CNAWM) was not significantly different at 78% and 56% for glioblastoma and brain metastases, respectively ( P > 0.05). CONCLUSIONS: Performing APT imaging under the same parameters used in this study may aid in the identification of brain tumors.


Assuntos
Neoplasias Encefálicas , Glioblastoma , Humanos , Glioblastoma/diagnóstico por imagem , Prótons , Amidas , Imageamento por Ressonância Magnética/métodos , Interpretação de Imagem Assistida por Computador/métodos , Neoplasias Encefálicas/diagnóstico por imagem , Neoplasias Encefálicas/patologia
13.
Heliyon ; 8(11): e11714, 2022 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-36439771

RESUMO

Caffeine is a psychoactive substance that not only improves wakefulness, but also slows the cognitive decline caused by aging. However, at present, there are no reports about the effects of caffeine withdrawal, including headaches and changes in brain functional networks (nerve activity). Headache may occur approximately 24 h after discontinuing caffeine intake in chronic caffeine drinkers. The current study aimed to examine the brain functional activity via resting-state functional magnetic resonance imaging in chronically caffeinated and decaffeinated groups to investigate changes in brain activity caused by caffeine. C57BL/6J mice were included in the analysis, and they underwent 9.4-T ultrahigh-field magnetic resonance imaging. The mice were classified into the control, chronic caffeinated, and caffeine withdrawal grsoups. Mice were divided into three groups: 1) not exposed to caffeine (control); 2) treated with caffeine at a concentration of 0.3 mg/mL for 4 weeks (chronic caffeinated); and 3) treated as before with caffeine and withdrawn from caffeine for 24 h. After the three groups were examined, functional connectivity matrices were calculated using brain imaging analysis tools, and independent component analysis was performed. The results showed that caffeine administration activated neural activity areas in the stress response system. Furthermore, 24h after caffeine withdrawal, the results showed an increase in pain-related neural activity. In addition, caffeine administration was shown to activate the dentate gyrus, one of the hippocampal regions, and to decrease the neural activity in the olfactory bulb and anterior cingulate cortex. In the current research, the neural activity of specific brain regions changed after chronic caffeine administration and withdrawal.

14.
Quant Imaging Med Surg ; 12(5): 2649-2657, 2022 May.
Artigo em Inglês | MEDLINE | ID: mdl-35502393

RESUMO

Background: To evaluate the possible clinical use of the compressed sensing-volumetric-interpolated breath-hold examination (CS-VIBE) in patients with liver tumors by evaluating tumor contrast enhancement effect by radiologists. Methods: We examined 22 patients with pathologically confirmed neoplastic lesions in the liver and 62 patients with lesions confirmed by imaging and clinical observation. To evaluate image quality, dynamic contrast-enhanced multiphase breath-hold magnetic resonance imaging was performed. The contrast agent used in this study was gadolinium-ethoxybenzyl-diethylenetriamine penta-acetic acid. Image quality was assessed by three radiologists experienced in this field. Using a four-point scale, we evaluated the gradual contrast enhancement effect of the portal vein to determine whether a decent arterial phase could be obtained. We assessed interobserver agreement using the Fleiss kappa to evaluate image quality between readers. The detection and evaluation of the tumor itself by its enhancement effects are very important in contrast studies. Thus, we evaluated the contrast enhancement effect of the tumors on a three-point scale in 26 patients already known to have hypervascularized tumors using ultrasound or computed tomography as assessed by experienced radiologists. Results: In terms of contrast enhancement effects of the portal vein, the mean value of the readers was 1.85 in the first phase, 2.07 in the second phase, 2.66 in the third phase, 3.05 in the fourth phase, and 3.24 in the fifth phase. Moreover, the interreader agreement was moderate (kappa 0.400-0.502) for all evaluated scores. In the signal of the portal vein, the score of the second arterial phase increased gradually, and in the third arterial phase, the mean score varied from 2 to 3. Compared with ultrasound or computed tomography, CS-VIBE identified 92.3% tumors with hypervascularized tumors (24 of 26 patients with findings hypervascularized tumors). In the results, the interreader agreement was fair to moderate (kappa 0.414-0.521). Conclusions: We obtained multiphase images, including at least one phase, which are useful for the evaluation of liver tumors. Furthermore, the radiologist was able to detect the tumor as before. Therefore, compressed sensing-volumetric-interpolated breath-hold examination is clinically useful in Ethoxybenzyl liver studies.

16.
Phys Med Biol ; 66(24)2021 12 16.
Artigo em Inglês | MEDLINE | ID: mdl-34874287

RESUMO

To reduce the determination errors of CSF pulsation in diffusion-weighted image (DWI) thermometry, we investigated whether applying second-order motion compensation diffusion tensor imaging (2nd-MC DTI) and fractional anisotropy (FA) processing improves the measurement of intracranial cerebrospinal fluid (CSF) temperature. In a phantom study, we investigated the relationship between temperature and FA in artificial CSF (ACSF) to determine the threshold for FA processing. The calculated temperatures of ACSF were compared with those of water. In a human study, 18 healthy volunteers were scanned using conventional DTI (c-DTI) and 2nd-MC DTI on a 3.0 T magnetic resonance imaging (MRI) system. A temperature map was created using diffusion coefficients from each DWI with/without FA processing. The temperatures of intracranial CSF were compared between each DTI image using Welch's analysis of variance and Games-Howell's multiple comparisons. In the phantom study, FA did not exceed 0.1 at any temperature. Consequently, pixels exceeding the threshold of 0.1 were removed from the temperature map. Intracranial CSF temperatures significantly differed between the four methods (p < 0.0001). The lowest temperature was 2nd-MC DTI with FA processing (mean, 35.62 °C), followed in order by c-DTI with FA processing (mean, 36.16 °C), 2nd-MC DTI (mean, 37.08 °C), and c-DTI (mean, 39.08 °C;p < 0.01 for each). Because the calculated temperature of ACSF was estimated to be lower than that of water, the temperature of 2nd-DTI with FA processing was considered reasonable. The method of 2nd-MC DTI with FA processing enabled determining intracranial CSF temperature with a reduction in CSF pulsation.


Assuntos
Imagem de Difusão por Ressonância Magnética , Imagem de Tensor de Difusão , Anisotropia , Imagem de Difusão por Ressonância Magnética/métodos , Imagem de Tensor de Difusão/métodos , Humanos , Temperatura , Água
17.
Neuroimage ; 241: 118413, 2021 11 01.
Artigo em Inglês | MEDLINE | ID: mdl-34293463

RESUMO

A few studies have compared the static functional connectivity between awake and lightly anesthetized states in rodents by resting-state fMRI. However, impact of light anesthesia on static and dynamic fluctuations in functional connectivity has not been fully understood. Here, we developed a resting-state fMRI protocol to perform awake and anesthetized functional MRI in the same mice. Static functional connectivity showed a widespread decrease under light anesthesia, such as when under isoflurane or a mixture of isoflurane and medetomidine. Several interhemispheric and subcortical connections were key connections for anesthetized condition from awake state. Dynamic functional connectivity demonstrates the shift from frequent broad connections across the cortex, the hypothalamus, and the auditory-visual cortex to frequent local connections within the cortex only under light anesthesia compared with awake state. Fractional amplitude of low frequency fluctuation in the thalamic nuclei decreased under both anesthesia. These results indicate that typical anesthetics for functional MRI alters the spatiotemporal profile of the dynamic brain network in subcortical regions, including the thalamic nuclei and limbic system.


Assuntos
Anestesia , Anestésicos Inalatórios/administração & dosagem , Encéfalo/fisiologia , Rede Nervosa/fisiologia , Vigília/fisiologia , Anestesia/métodos , Animais , Encéfalo/diagnóstico por imagem , Encéfalo/efeitos dos fármacos , Imageamento por Ressonância Magnética/métodos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Rede Nervosa/diagnóstico por imagem , Rede Nervosa/efeitos dos fármacos , Vigília/efeitos dos fármacos
18.
J Belg Soc Radiol ; 105(1): 14, 2021 Mar 16.
Artigo em Inglês | MEDLINE | ID: mdl-33778369

RESUMO

BACKGROUND: Solitary fibrous tumors (SFTs) are rare and can be misdiagnosed because of their various radiological appearances. PURPOSE: To clarify the characteristic MRI findings of SFTs by analyzing their radiological-pathological correlation. MATERIAL AND METHODS: Nine consecutive patients with SFT who underwent magnetic resonance imaging (MRI) prior to surgery were analyzed. Eight patients underwent contrast-enhanced MRI, and three underwent dynamic MRI. Radiological-pathological correlation analysis, co-occurrence matrix, run-length matrix, and histogram analysis were performed to assess the relationship between pathological findings T1- and T2-weighted images (T1-WI and T2-WI). RESULTS: All nine lesions ranged in size from 20 to 36 mm. Seven lesions were located in the superior portion of the retrobulbar space found outside of the muscle cone, and two lesions in the inferior portion were located within it. No significant correlation was observed between the amount of collagenous tissue and the qualitative evaluation of the signal on T1-WI and T2-WI. Kurtosis on T2-WI was significantly correlated with the amount of collagenous tissue (ρ = -0.97, p < 0.0001) and endothelial cells (ρ = -0.49, p = 0.0479). CONCLUSION: Kurtosis in the histogram analysis on T2WI showed a strong correlation with the amount of collagenous tissue.

19.
J Comput Assist Tomogr ; 45(2): 277-284, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33661152

RESUMO

PURPOSE: The aims of this study were to evaluate the relationship between age change and amide proton transfer (APT) signal in each region of the whole brain and to derive the standard value of APT signal in each brain region of normal adults. MATERIALS AND METHODS: Using the mDIXON 3-dimensional-APT sequence of the fast spin echo method, an APT image was obtained. In total, 60 patients (mean age, 49.8 ± 16.9 years) with no abnormal findings on magnetic resonance imaging data were included. For image analysis, registration parameters were created using the FMRIB Software Library 5.0.11, and then a region of interest was set in the Montreal Neurological Institute structural atlas for analysis. Statistical analyses were performed using the age-dependent and sex differences in APT signals from each brain region. RESULTS: No significant correlation was seen between APT signal and age and sex in all brain regions. CONCLUSION: Under the APT imaging parameter conditions used in this study, local brain APT signals in healthy adults are independent of age and sex.


Assuntos
Química Encefálica/fisiologia , Encéfalo/diagnóstico por imagem , Imageamento por Ressonância Magnética/métodos , Proteínas do Tecido Nervoso/análise , Adulto , Fatores Etários , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Proteínas do Tecido Nervoso/química , Fatores Sexuais , Adulto Jovem
20.
Magn Reson Imaging ; 73: 186-191, 2020 11.
Artigo em Inglês | MEDLINE | ID: mdl-32890672

RESUMO

PURPOSE: To compare the imaging characteristics of the volumetric-interpolated breath-hold examination (VIBE) using compressed-sensing (CS) acceleration (CS-VIBE) with the conventional sequence relying on parallel imaging to assess the potential use of CS-VIBE as a functional imaging technique for upper abdominal haemodynamics. MATERIALS AND METHODS: Patients (30 men, 27 women) suspected of having a hepatic disease underwent magnetic resonance imaging (MRI) of the liver, including a dynamic contrast-enhanced study. Gadolinium-ethoxybenzyl-diethylenetriamine pentaacetic acid was used as the contrast agent. MRI data of two multi-phase breath-hold exams were used for intra-individual comparisons. The VIBE and CS-VIBE were performed on different days. Image quality in both sequences was qualitatively assessed by three experienced radiologists. Moreover, the contrast ratio (CR) of the aorta, portal vein, liver and pancreas to muscle tissue were measured as a quantitative assessment. For the CS-VIBE, a five-phase time-intensity curve (TIC) was created to evaluate haemodynamics. The measurement area included the pancreas, common hepatic artery, portal vein and superior mesenteric vein. The ratio of that area to the muscle tissue in the same cross section was used to create the TICs. RESULTS: The qualitative assessment showed that artefacts were significantly different between the VIBE and CS-VIBE sequences. This finding indicated that the conventional VIBE had fewer artefacts. The CR was significantly higher for the CS-VIBE than for the VIBE images in all phases (p < 0.001). An evaluation of haemodynamics compared with those obtained by CT angiography showed almost the same temporal characteristics in the common hepatic artery, portal vein and superior mesenteric vein signals as those in a previous study. CONCLUSION: Compared with the conventional VIBE, the CS-VIBE had significantly higher temporal resolution and higher image contrast. The temporal resolution of the CS-VIBE was sufficient for viewing abdominal haemodynamics. If the remaining limitation of acquisition speed for dynamic MRI can be adequately addressed, we believe that CS-VIBE functional images with high-contrast haemodynamics will be very useful in clinical practise.


Assuntos
Abdome/irrigação sanguínea , Hemodinâmica , Imageamento por Ressonância Magnética/métodos , Abdome/diagnóstico por imagem , Adulto , Idoso , Artefatos , Suspensão da Respiração , Meios de Contraste , Feminino , Gadolínio DTPA , Artéria Hepática/diagnóstico por imagem , Artéria Hepática/fisiologia , Humanos , Masculino , Pessoa de Meia-Idade , Veia Porta/diagnóstico por imagem , Veia Porta/fisiologia
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