RESUMEN
AIM: We developed an augmented reality technology-based endotracheal aspiration simulation tool (the AR tool) consisting of three modes: a mode for nursing students to learn endotracheal aspiration by themselves (learning mode); a mode for repeated practice (practice mode); and a mode for confirmation testing (test mode). This study aimed to compare the learning outcomes of the AR tool with traditional training mannequins and identify potential uses and improvements of the AR tool. METHODS: We invited students, and faculty members from the three universities who agreed to cooperate in conducting this study. Fifty-four students and nine faculty members agreed to participate in this study. The students were divided into two groups. One group was to study with the AR tool and the other group was to study with the traditional half-body training mannequin for suction. The students in both groups were asked to demonstrate endotracheal aspiration on another full-body type training mannequin which could be used as a patient with a tracheostomy (Skill test). Group interviews with faculty members focused on the topic of the AR tool's potential use in nursing education and improvement needed. RESULTS: There was little significant difference in the skill test results of endotracheal aspiration of students in both groups. The students and faculty members both expressed an interest in the AR tool. They said it was suitable for self-study of endotracheal aspiration. CONCLUSIONS: This AR tool is an effective teaching tool for learning the sequence of endotracheal suctioning, although there are some areas that need improvement.
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Realidad Aumentada , Educación en Enfermería , Estudiantes de Enfermería , Humanos , Maniquíes , Aprendizaje , EstudiantesRESUMEN
BACKGROUND: Early brain injury (EBI) after subarachnoid hemorrhage (SAH) is a new therapeutic target. Sulfonylurea receptor 1 (SUR1) is expressed in nerve cells, glial cells, and vascular endothelial cells in EBI. SUR1 promotes intracellular inflow of Na and Ca ions, resulting in cell swelling and depolarization, and finally cell death. Glibenclamide reduced cerebral edema and mortality in a basic study of cerebral ischemia. However, the effects of glibenclamide on EBI have not been fully elucidated. This study examined the inhibitory effect of glibenclamide on EBI. METHODS: Rats were divided into the sham group, SAH-control group, and SAH-glibenclamide group. The water content of the brain was measured using the dry-wet method. In addition, the brain was divided into the cortex, putamen, and hippocampus, and expression of inflammatory cytokines was evaluated by the polymerase chain reaction method. In addition, microglia in the brain were evaluated immunohistologically. RESULTS: Water content of the brain was significantly decreased in the SAH-glibenclamide group compared to the SAH-control group. Interleukin-1beta (IL-1ß), tumor necrosis factor alpha (TNFα), and nuclear factor-kappa B significantly increased in the cerebral cortex after SAH. IL-1ß and TNFα in the cortex were significantly decreased in the SAH-glibenclamide group compared to the SAH-control group. Immunohistochemical staining confirmed that SAH causes extensive microglial activation in the brain, which was suppressed by glibenclamide. CONCLUSIONS: The present study showed that glibenclamide suppressed cerebral edema and activation of microglia and hypersecretion of inflammatory cytokines. Glibenclamide is a potential therapeutic method which may significantly improve the functional prognosis.
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Edema Encefálico , Lesiones Encefálicas , Neoplasias Encefálicas , Hemorragia Subaracnoidea , Ratas , Animales , Edema Encefálico/tratamiento farmacológico , Edema Encefálico/etiología , Gliburida/farmacología , Gliburida/uso terapéutico , Factor de Necrosis Tumoral alfa/uso terapéutico , Hemorragia Subaracnoidea/tratamiento farmacológico , Hemorragia Subaracnoidea/complicaciones , Ratas Sprague-Dawley , Células Endoteliales/metabolismo , Células Endoteliales/patología , Lesiones Encefálicas/tratamiento farmacológico , Lesiones Encefálicas/complicaciones , Citocinas , Neoplasias Encefálicas/complicacionesRESUMEN
Chemical exchange saturation transfer (CEST) magnetic resonance imaging (MRI) has emerged as a novel means for sensitive detection of dilute labile protons and chemical exchange rates. By sensitizing to pH-dependent chemical exchange, CEST MRI has shown promising results in monitoring tissue statuses such as pH changes in disorders like acute stroke, tumor, and acute kidney injury. This article briefly reviews the basic principles for CEST imaging and quantitative measures, from the simplistic asymmetry analysis to multipool Lorentzian decoupling and quasi-steady-state reconstruction. In particular, the advantages and limitations of commonly used quantitative approaches for CEST applications are discussed.
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Interpretación de Imagen Asistida por Computador , Accidente Cerebrovascular , Humanos , Interpretación de Imagen Asistida por Computador/métodos , Protones , Concentración de Iones de Hidrógeno , Imagen por Resonancia Magnética/métodos , Fantasmas de ImagenRESUMEN
BACKGROUND: Coronavirus infections are spreading rapidly worldwide, and primary and middle schools are closed in many countries. After the state of emergency was lifted in Japan, schools have reopened, and teachers are conducting face-to-face classes while maintaining safety precautions. This study aimed to assess the factors contributing to infection-related anxiety and educational anxiety among teachers conducting face-to-face classes during the COVID-19 pandemic after schools reopened. METHODS: This questionnaire-based cross-sectional study was conducted with 263 primary and middle school teachers in the Shinagawa area of Tokyo (October 10-30, 2020). The questionnaire assessed the type of school (primary or middle school), sex, age, and factors contributing to infection-related anxiety and educational anxiety that arose from the pandemic. The levels of anxiety and the factors contributing to anxiety were assessed using a 5-point Likert scale ranging from 1 (not at all) to 5 (very anxious). RESULTS: In an analysis of the data of 237 participants excluding the missing data, many teachers reported feeling infection- and education-related anxiety. A majority of the participants were women (n = 152, 64.1%), and the mean age of the participants was 39.8 ± 11.3 years. A stepwise multiple regression analysis identified six factors for infection-related anxiety as significant (R2 = 0.61, p < 0.001). Among these variables, the largest partial regression coefficient value was reported for the following reason: "I feel anxious because we cannot ensure the safety of teachers themselves or of their families" (ß = 0.37, p < 0.001). For educational anxiety, four of six reasons were identified as significant (R2 = 0.64, p < 0.001). Among these, "anxiety about the students' home situations" (ß = 0.41, p < 0.001) and "delay in education (students' side)" (ß = 0.27, p < 0.001) had stronger associations with anxiety compared to the others. CONCLUSION: In-person education during the COVID-19 pandemic has caused teachers to experience anxiety. This report provides useful information by highlighting the reasons for infection-related anxiety and educational anxiety that teachers experience in face-to-face classes during a pandemic. Even if the coverage of a COVID-19 vaccine becomes widespread worldwide, we will still be combating COVID-19 infections for at least a few years. Given concerns regarding such infections, to ensure students' right to education, it is essential to understand why teachers feel anxious and to determine appropriate measures to decrease such anxiety.
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COVID-19 , Pandemias , Adulto , Ansiedad/epidemiología , Vacunas contra la COVID-19 , Estudios Transversales , Femenino , Humanos , Japón/epidemiología , Masculino , Persona de Mediana Edad , SARS-CoV-2 , Instituciones Académicas , TokioRESUMEN
A 28-year-old woman experienced severe headache and right homonymous hemianopia after receiving high-dose infliximab for Crohn's disease. Computed tomography showed hemorrhagic infarction in the left temporal and parietal lobes. An angiogram revealed left transverse to sigmoid sinus occlusion and a stagnated Labbe vein. The patient was treated surgically and achieved a good outcome. Inflammatory bowel diseases are known to accompany venous and arterial thrombosis in 1-2% of cases. Recently, infliximab has been suggested to increase this possibility. A case of Crohn's disease presenting with cerebral sinus thrombosis in the remission period during long-term/high-dose use of infliximab is presented. In addition, infliximab-associated thrombosis cases were reviewed.
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Trombosis de los Senos Intracraneales , Adulto , Femenino , Humanos , Infliximab/efectos adversos , Trombosis de los Senos Intracraneales/diagnóstico , Trombosis de los Senos Intracraneales/diagnóstico por imagen , Tomografía Computarizada por Rayos XRESUMEN
BACKGROUND: Endovascular thrombectomy (EVT) is highly effective but may also lead to hemorrhagic transformation (HT) and edema, which may be more pronounced in severe ischemia. We sought to determine whether glibenclamide can attenuate HT and edema in a severe ischemia-reperfusion model that reflects EVT. METHODS: Using a transient middle cerebral artery occlusion (tMCAo) rodent model of stroke, we studied two rat cohorts, one without rt-PA and a second cohort treated with rt-PA. Glibenclamide or vehicle control was administered as an intravenous bolus at reperfusion, followed by continuous subcutaneous administration with an osmotic pump. RESULTS: Compared to vehicle control, glibenclamide improved neurological outcome (median 7, interquartile range [IQR 6-8] vs. control median 6 [IQR 0-6], p = 0.025), reduced stroke volume (323 ± 42 vs. 484 ± 60 mm3, p < 0.01), swelling volume (10 ± 4 vs. 28 ± 7%, p < 0.01) and water content (84 ± 1 vs. 85 ± 1%, p < 0.05). Glibenclamide administration also reduced HT based on ECASS criteria, densitometry (0.94 ± 0.1 vs. 1.15 ± 0.2, p < 0.01), and quantitative hemoglobin concentration (2.7 ± 1.5 vs. 6.2 ± 4.6 uL, p = 0.011). In the second cohort with rt-PA coadministration, concordant effects on HT were observed with glibenclamide. CONCLUSIONS: Taken together, these studies demonstrated that glibenclamide reduced the amount of edema and HT after severe ischemia. This study suggests that co-administration of glibenclamide may be worth further study in severe stroke patients treated with EVT with or without IV rt-PA.
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Edema Encefálico/prevención & control , Gliburida/administración & dosificación , Infarto de la Arteria Cerebral Media/tratamiento farmacológico , Hemorragias Intracraneales/prevención & control , Fármacos Neuroprotectores/administración & dosificación , Daño por Reperfusión/tratamiento farmacológico , Animales , Edema Encefálico/diagnóstico por imagen , Edema Encefálico/patología , Modelos Animales de Enfermedad , Fibrinolíticos/farmacología , Infarto de la Arteria Cerebral Media/diagnóstico por imagen , Infarto de la Arteria Cerebral Media/patología , Infusiones Subcutáneas , Inyecciones Intravenosas , Hemorragias Intracraneales/diagnóstico por imagen , Hemorragias Intracraneales/patología , Masculino , Ratas Wistar , Daño por Reperfusión/diagnóstico por imagen , Daño por Reperfusión/patología , Terapia Trombolítica , Activador de Tejido Plasminógeno/farmacologíaRESUMEN
BACKGROUND: In the revised World Health Organization 2016 classification of central nervous system tumors, "diffuse midline glioma, H3 K27M-mutant" has been added as a new diagnostic entity. However, some confusion exists concerning this diagnostic entity because H3 K27M-mutant diffuse midline glioma is diagnosed with grade IV regardless of morphologic phenotype. Furthermore, the significance of H3 K27M mutation in tumors that aren't typical "diffuse midline glioma, H3 K27M-mutant," such as those with an unusual location and nontypical histology, remains unclear. CASE DESCRIPTION: To elucidate further such unusual tumors, we describe here a rare case of pediatric low-grade glioma located in the tectum, which was morphologically a pilocytic astrocytoma (PA) with genetically H3 K27M mutation but no microvascular proliferation, necrosis, mitoses, or other genetic alterations, insofar as we were able to observe. At the latest follow-up, 28 months after surgery, radiotherapy, and chemotherapy, the patient was found to be free from any neurologic deficits and MRI demonstrated that the tumor was stable without tumor regrowth. This case might be identified as "diffuse midline glioma, H3 K27M-mutant", grade IV, when applying only the current World Health Organization 2016 classification. In addition, we discuss the morphologically benign gliomas harboring the H3 K27M mutation based on the literature. CONCLUSIONS: We describe here a rare case and present a short literature review of circumscribed/nondiffuse gliomas, particularly in PA with H3 K27M mutation. However, the significance of H3 K27M mutation for PA remains unclear, so further studies and clinical data are needed to elucidate the biology and optimal treatment of such tumors.
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Astrocitoma/genética , Astrocitoma/patología , Neoplasias Encefálicas/genética , Neoplasias Encefálicas/patología , Histonas/genética , Techo del Mesencéfalo/patología , Adolescente , Astrocitoma/diagnóstico por imagen , Neoplasias Encefálicas/diagnóstico por imagen , Femenino , Humanos , Mutación , Clasificación del Tumor , Techo del Mesencéfalo/diagnóstico por imagenRESUMEN
Recurrent intestinal inflammation and refractory perianal abscesses are typical manifestations of Crohn's disease. However, these conditions are not always due to Crohn's disease. A 25-year-old male with recurrent perianal abscesses for 1 year, suspected to be due to Crohn's disease, was referred for further evaluation. Computed tomography scan showed a perianal abscess abutting the small intestine. A complicated Meckel's diverticulum was suspected based on these findings. Meckel's diverticulum scintigraphy was negative. Bidirectional double-balloon endoscopy (DBE) identified a long diverticulum in the ileum. In this long diverticulum, a tight stricture was seen 5 cm distal to the diverticular opening. A selective contrast study showed a 10 cm diverticulum distal to the stricture, with three strictures in the long diverticulum. Inflammation of the Meckel's diverticulum due to bacterial overgrowth was suspected as a cause of the refractory perianal abscesses. Laparoscopic diverticulectomy was performed, and the specimen showed a 10 cm diverticulum containing post-inflammatory changes with scar formation. The perianal abscess was confirmed to be caused by an inflamed Meckel's diverticulum. The patient has been asymptomatic for 6 years after resection. DBE before exploratory laparotomy should be considered to investigate the cause of an abscess that could be secondary to small intestinal pathology.
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Absceso/diagnóstico , Enfermedades del Ano/diagnóstico , Enfermedad de Crohn/diagnóstico , Diagnóstico Diferencial , Diverticulitis/diagnóstico , Divertículo Ileal/diagnóstico , Absceso/etiología , Adulto , Enfermedades del Ano/etiología , Constricción Patológica , Diverticulitis/complicaciones , Diverticulitis/patología , Enteroscopía de Doble Balón , Humanos , Laparoscopía , Masculino , Divertículo Ileal/complicaciones , Divertículo Ileal/patología , Recurrencia , Tomografía Computarizada por Rayos XRESUMEN
A subependymoma is a benign primary brain tumor classified as a World Health Organization grade I tumor; it is asymptomatic in most cases. We present the case of a 66-year-old Japanese man with a complaint of recurrent vomiting that led to the discovery of a large mass with hemorrhage, peritumoral edema, and a midline shift in the posterior horn of the right lateral ventricle. The patient was pathologically diagnosed with subependymoma after undergoing total tumor resection; a year after the surgery, he was free from tumor recurrence. Although symptomatic subependymomas are rare, they tend to show hemorrhage with peritumoral edema on neuroradiological tests and tend to be confused with high-grade brain tumors. In the present case, we highlight the importance of the appropriate diagnosis for subependymomas showing neuroradiological features that mimic high-grade gliomas. This diagnosis will help in providing suitable treatment for subependymomas
Un subependimoma es un tumor cerebral primario benigno, clasificado por la Organización Mundial de la Salud como un tumor grado I. En la mayoría de los casos es asintomático. Presentamos el caso de un varón japonés de 66 años de edad que reportaba vómitos recurrentes, los que lo llevaron al descubrimiento de una gran masa con hemorragia, edema peritumoral y una desviación de la línea media del cuerno posterior del ventrículo lateral derecho. Se le realizó un diagnóstico patológico de subependimoma luego de que se le sometiera a una resección total del tumor. Un año después de la cirugía no presentaba recurrencia del tumor. Aunque los subependimomas sintomáticos son raros, en las pruebas neurorradiológicas tienden a presentar hemorragia con edema peritumoral y se tiende a confundirlos con tumores cerebrales de alto grado. En el presente caso, destacamos la importancia de un diagnóstico adecuado de los subependimomas que presentan características neurorradiológicas que imitan a gliomas de alto grado. Este diagnóstico ayudará a brindar el tratamiento adecuado para dichos subependimomas
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Humanos , Masculino , Anciano , Glioma Subependimario/diagnóstico por imagen , Glioma Subependimario/radioterapia , Hemorragia Cerebral/complicaciones , Neoplasias Encefálicas/cirugía , Neurocirugia , Glioma Subependimario/patología , Edema Encefálico/complicaciones , Edema Encefálico/diagnóstico por imagen , Inmunohistoquímica , Diagnóstico Diferencial , Ventrículos Cerebrales/cirugíaRESUMEN
pH-weighted amide proton transfer (APT) MRI is sensitive to tissue pH change during acute ischemia, complementing conventional perfusion and diffusion stroke imaging. However, the currently used pH-weighted magnetization transfer (MT) ratio asymmetry (MTRasym) analysis is of limited pH specificity. To overcome this, MT and relaxation normalized APT (MRAPT) analysis has been developed that to homogenize the background signal, thus providing highly pH conspicuous measurement. Our study aimed to calibrate MRAPT MRI toward absolute tissue pH mapping and determine regional pH changes during acute stroke. Using middle cerebral artery occlusion (MCAO) rats, we performed lactate MR spectroscopy and multi-parametric MRI. MRAPT MRI was calibrated against a region of interest (ROI)-based pH spectroscopy measurement (R2â¯=â¯0.70, Pâ¯<â¯0.001), showing noticeably higher correlation coefficient than the simplistic MTRasym index. Capitalizing on this, we mapped brain tissue pH and semi-automatically segmented pH lesion, in addition to routine perfusion and diffusion lesions. Tissue pH from regions of the contralateral normal, perfusion/diffusion lesion mismatch and diffusion lesion was found to be 7.03⯱â¯0.04, 6.84⯱â¯0.10, 6.52⯱â¯0.19, respectively. Most importantly, we delineated the heterogeneous perfusion/diffusion lesion mismatch into perfusion/pH and pH/diffusion lesion mismatches, with their pH being 7.01⯱â¯0.04 and 6.71⯱â¯0.12, respectively (Pâ¯<â¯0.05). To summarize, our study calibrated pH-sensitive MRAPT MRI toward absolute tissue pH mapping, semi-automatically segmented and determined graded tissue pH changes in ischemic tissue and demonstrated its feasibility for refined demarcation of heterogeneous metabolic disruption following acute stroke.
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Encéfalo/metabolismo , Concentración de Iones de Hidrógeno , Imagen por Resonancia Magnética/métodos , Accidente Cerebrovascular/metabolismo , Animales , Encéfalo/patología , Modelos Animales de Enfermedad , Masculino , Ratas , Ratas WistarRESUMEN
A subependymoma is a benign primary brain tumor classified as a World Health Organization grade I tumor; it is asymptomatic in most cases. We present the case of a 66-year-old Japanese man with a complaint of recurrent vomiting that led to the discovery of a large mass with hemorrhage, peritumoral edema, and a midline shift in the posterior horn of the right lateral ventricle. The patient was pathologically diagnosed with subependymoma after undergoing total tumor resection; a year after the surgery, he was free from tumor recurrence. Although symptomatic subependymomas are rare, they tend to show hemorrhage with peritumoral edema on neuroradiological tests and tend to be confused with high-grade brain tumors. In the present case, we highlight the importance of the appropriate diagnosis for subependymomas showing neuroradiological features that mimic high-grade gliomas. This diagnosis will help in providing suitable treatment for subependymomas.
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Neoplasias Encefálicas/patología , Glioma Subependimario/patología , Anciano , Neoplasias Encefálicas/complicaciones , Neoplasias Encefálicas/diagnóstico por imagen , Neoplasias Encefálicas/cirugía , Hemorragia Cerebral/etiología , Diagnóstico Diferencial , Glioma/diagnóstico por imagen , Glioma/patología , Glioma/cirugía , Glioma Subependimario/complicaciones , Glioma Subependimario/diagnóstico por imagen , Glioma Subependimario/cirugía , Humanos , Imagen por Resonancia Magnética , Masculino , Tomografía Computarizada por Rayos X , Vómitos/etiologíaRESUMEN
PURPOSE: To extend the pH detection range of iopamidol-based ratiometric chemical exchange saturation transfer (CEST) MRI at sub-high magnetic field and establish quantitative renal pH MRI. METHODS: Chemical exchange saturation transfer imaging was performed on iopamidol phantoms with pH of 5.5 to 8.0 and in vivo on rat kidneys (n = 5) during iopamidol administration at a 4.7 T. Iopamidol CEST effects were described using a multipool Lorentzian model. A generalized ratiometric analysis was conducted by ratioing resolved iopamidol CEST effects at 4.3 and 5.5 ppm obtained under 1.0 and 2.0 µT, respectively. The pH detection range was established for both the standard ratiometric analysis and the proposed resolved approach. Renal pH was mapped in vivo with regional pH assessed by one-way analysis of variance. RESULTS: Good-fitting performance was observed in multipool Lorentzian resolving of CEST effects (R2 s > 0.99). The proposed approach extends the in vitro pH detection range to 5.5 to 7.5 at 4.7 T. In vivo renal pH was measured to be 7.0 ± 0.1, 6.8 ± 0.1, and 6.5 ± 0.2 for cortex, medulla and calyx, respectively (P < 0.05). CONCLUSIONS: The proposed ratiometric approach extended the iopamidol pH detection range, enabling the renal pH mapping in vivo, which is promising for pH imaging studies at sub-high or low fields with potential clinical applicability. Magn Reson Med 79:1553-1558, 2018. © 2017 International Society for Magnetic Resonance in Medicine.
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Medios de Contraste/uso terapéutico , Procesamiento de Imagen Asistido por Computador/métodos , Yopamidol/uso terapéutico , Riñón/diagnóstico por imagen , Imagen por Resonancia Magnética/métodos , Algoritmos , Animales , Concentración de Iones de Hidrógeno , Masculino , Fantasmas de Imagen , Ratas , Ratas WistarRESUMEN
Diffusion weighted imaging (DWI) has been commonly used in acute stroke examination, yet a portion of DWI lesion may be salvageable. Recently, it has been shown that diffusion kurtosis imaging (DKI) defines the most severely damaged DWI lesion that does not renormalize following early reperfusion. We postulated that the diffusion and kurtosis lesion mismatch experience heterogeneous hemodynamic and/or metabolic injury. We investigated tissue perfusion, pH, diffusion, kurtosis and relaxation from regions of the contralateral normal area, diffusion lesion, kurtosis lesion and their mismatch in an animal model of acute stroke. Our study revealed significant kurtosis and diffusion lesion volume mismatch (19.7 ± 10.7%, P < 0.01). Although there was no significant difference in perfusion and diffusion between the kurtosis lesion and kurtosis/diffusion lesion mismatch, we showed lower pH in the kurtosis lesion (pH = 6.64 ± 0.12) from that of the kurtosis/diffusion lesion mismatch (6.84 ± 0.11, P < 0.05). Moreover, pH in the kurtosis lesion and kurtosis/diffusion mismatch agreed well with literature values for regions of ischemic core and penumbra, respectively. Our work documented initial evidence that DKI may reveal the heterogeneous metabolic derangement within the commonly used DWI lesion.
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Isquemia Encefálica/diagnóstico por imagen , Imagen de Difusión por Resonancia Magnética/métodos , Imagen de Difusión Tensora/métodos , Concentración de Iones de Hidrógeno , Animales , Difusión , Modelos Animales de Enfermedad , Perfusión , Ratas , Accidente Cerebrovascular/diagnóstico por imagenRESUMEN
Diffusion kurtosis imaging (DKI) has been shown to augment diffusion-weighted imaging (DWI) for the definition of irreversible ischemic injury. However, the complexity of cerebral structure/composition makes the kurtosis map heterogeneous, limiting the specificity of kurtosis hyperintensity to acute ischemia. We propose an Inherent COrrelation-based Normalization (ICON) analysis to suppress the intrinsic kurtosis heterogeneity for improved characterization of heterogeneous ischemic tissue injury. Fast DKI and relaxation measurements were performed on normal (n = 10) and stroke rats following middle cerebral artery occlusion (MCAO) (n = 20). We evaluated the correlations between mean kurtosis (MK), mean diffusivity (MD) and fractional anisotropy (FA) derived from the fast DKI sequence and relaxation rates R1 and R2 , and found a highly significant correlation between MK and R1 (p < 0.001). We showed that ICON analysis suppressed the intrinsic kurtosis heterogeneity in normal cerebral tissue, enabling automated tissue segmentation in an animal stroke model. We found significantly different kurtosis and diffusivity lesion volumes: 147 ± 59 and 180 ± 66 mm3 , respectively (p = 0.003, paired t-test). The ratio of kurtosis to diffusivity lesion volume was 84% ± 19% (p < 0.001, one-sample t-test). We found that relaxation-normalized MK (RNMK), but not MD, values were significantly different between kurtosis and diffusivity lesions (p < 0.001, analysis of variance). Our study showed that fast DKI with ICON analysis provides a promising means of demarcation of heterogeneous DWI stroke lesions.
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Encéfalo/diagnóstico por imagen , Encéfalo/patología , Imagen de Difusión por Resonancia Magnética/métodos , Interpretación de Imagen Asistida por Computador/métodos , Infarto de la Arteria Cerebral Media/diagnóstico por imagen , Infarto de la Arteria Cerebral Media/patología , Reconocimiento de Normas Patrones Automatizadas/métodos , Enfermedad Aguda , Algoritmos , Animales , Aumento de la Imagen/métodos , Aprendizaje Automático , Masculino , Modelos Biológicos , Modelos Estadísticos , Ratas , Ratas Wistar , Reproducibilidad de los Resultados , Sensibilidad y Especificidad , Estadística como AsuntoRESUMEN
Chemical exchange saturation transfer (CEST) provides sensitive magnetic resonance (MR) contrast for probing dilute compounds via exchangeable protons, serving as an emerging molecular imaging methodology. CEST Z-spectrum is often acquired by sweeping radiofrequency saturation around bulk water resonance, offset by offset, to detect CEST effects at characteristic chemical shift offsets, which requires prolonged acquisition time. Herein, combining high-resolution magic angle spinning (HRMAS) with concurrent application of gradient and rf saturation to achieve fast Z-spectral acquisition, we demonstrated the feasibility of fast quantitative HRMAS CEST Z-spectroscopy. The concept was validated with phantoms, which showed excellent agreement with results obtained from conventional HRMAS MR spectroscopy (MRS). We further utilized the HRMAS Z-spectroscopy for fast ex vivo quantification of ischemic injury with rodent brain tissues after ischemic stroke. This method allows rapid and quantitative CEST characterization of biological tissues and shows potential for a host of biomedical applications.
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Química Encefálica , Isquemia Encefálica/patología , Encéfalo/patología , Medios de Contraste/química , Imagen por Resonancia Magnética/métodos , Animales , Espectroscopía de Resonancia Magnética/métodos , Masculino , Fantasmas de Imagen , Protones , Ratas WistarRESUMEN
pH-sensitive amide proton transfer (APT) MRI provides a surrogate metabolic biomarker that complements the widely-used perfusion and diffusion imaging. However, the endogenous APT MRI is often calculated using the asymmetry analysis (MTRasym), which is susceptible to an inhomogeneous shift due to concomitant semisolid magnetization transfer (MT) and nuclear overhauser (NOE) effects. Although the intact brain tissue has little pH variation, white and gray matter appears distinct in the MTRasym image. Herein we showed that the heterogeneous MTRasym shift not related to pH highly correlates with MT ratio (MTR) and longitudinal relaxation rate (R1w), which can be reasonably corrected using the multiple regression analysis. Because there are relatively small MT and R1w changes during acute stroke, we postulate that magnetization transfer and relaxation-normalized APT (MRAPT) analysis increases MRI specificity to acidosis over the routine MTRasym image, hence facilitates ischemic lesion segmentation. We found significant differences in perfusion, pH and diffusion lesion volumes (P<0.001, ANOVA). Furthermore, MRAPT MRI depicted graded ischemic acidosis, with the most severe acidosis in the diffusion lesion (-1.05±0.29%/s), moderate acidification within the pH/diffusion mismatch (i.e., metabolic penumbra, -0.67±0.27%/s) and little pH change in the perfusion/pH mismatch (i.e., benign oligemia, -0.04±0.14%/s), providing refined stratification of ischemic tissue injury.
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Amidas/química , Química Encefálica , Encéfalo/diagnóstico por imagen , Concentración de Iones de Hidrógeno , Imagen por Resonancia Magnética/métodos , Accidente Cerebrovascular/diagnóstico por imagen , Accidente Cerebrovascular/metabolismo , Algoritmos , Amidas/metabolismo , Animales , Biomarcadores/química , Interpretación de Imagen Asistida por Computador/métodos , Campos Magnéticos , Masculino , Protones , Ratas , Ratas Wistar , Reproducibilidad de los Resultados , Sensibilidad y EspecificidadRESUMEN
Diffusion kurtosis imaging (DKI) can offer a useful complementary tool to routine diffusion MRI for improved stratification of heterogeneous tissue damage in acute ischemic stroke. However, its relatively long imaging time has hampered its clinical application in the emergency setting. A recently proposed fast DKI approach substantially shortens the imaging time, which may help to overcome the scan time limitation. However, to date, the sensitivity of the fast DKI protocol for the imaging of acute stroke has not been fully described. In this study, we performed routine and fast DKI scans in a rodent model of acute stroke, and compared the sensitivity of diffusivity and kurtosis indices (i.e. axial, radial and mean) in depicting acute ischemic lesions. In addition, we analyzed the contrast-to-noise ratio (CNR) between the ipsilateral ischemic and contralateral normal regions using both conventional and fast DKI methods. We found that the mean kurtosis shows a relative change of 47.1 ± 7.3% between the ischemic and contralateral normal regions, being the most sensitive parameter in revealing acute ischemic injury. The two DKI methods yielded highly correlated diffusivity and kurtosis measures and lesion volumes (R(2) ⩾ 0.90, p < 0.01). Importantly, the fast DKI method exhibited significantly higher CNR of mean kurtosis (1.6 ± 0.2) compared with the routine tensor protocol (1.3 ± 0.2, p < 0.05), with its CNR per unit time (CNR efficiency) approximately doubled when the scan time was taken into account. In conclusion, the fast DKI method provides excellent sensitivity and efficiency to image acute ischemic tissue damage, which is essential for image-guided and individualized stroke treatment.
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Isquemia Encefálica/complicaciones , Isquemia Encefálica/diagnóstico , Imagen de Difusión por Resonancia Magnética/métodos , Imagen de Difusión Tensora/métodos , Interpretación de Imagen Asistida por Computador , Accidente Cerebrovascular/complicaciones , Accidente Cerebrovascular/diagnóstico , Animales , Modelos Animales de Enfermedad , Masculino , Ratas WistarRESUMEN
We aimed to evaluate the usefulness of a newly developed, near-infrared spectroscopy (NIRS) device for monitoring hemodynamic changes during carotid artery stenting (CAS), as a means to detect filter obstruction due to distal embolism. We evaluated 16 patients with internal carotid artery (ICA) stenosis during the CAS procedure, using a NIRS system that can monitor not only changes in oxygenation of hemoglobin (Hb), but also the fluctuation of oxyhemoglobin (oxy-Hb) synchronized with heartbeat. The NIRS system detected a marked decrease of oxy-Hb and an increase of deoxyhemoglobin (deoxy-Hb) during ICA occlusion in patients without anterior cross circulation (ACC). Patients with ACC showed much smaller changes. The analysis of oxy-Hb fluctuation made it possible to detect occurrence of no-flow in the absence of Hb concentration changes. The amplitude of oxy-Hb fluctuation in the no/slow-flow group was significantly smaller than that in the normal-flow group. Our results indicate that the present high time-resolution NIRS device, which can measure oxy-Hb fluctuation, is superior to conventional NIRS for detecting filter obstruction.
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Arterias Carótidas/cirugía , Espectroscopía Infrarroja Corta/métodos , Stents , Anciano , Femenino , Hemoglobinas/análisis , Humanos , Masculino , Persona de Mediana Edad , Oxihemoglobinas/análisisRESUMEN
No systematic study is yet available that focuses on the surgical anatomy of the superior petrosal vein and its significance during surgery for cerebellopontine angle meningiomas. The aim of the present study was to examine the variation of the superior petrosal vein via the retrosigmoid suboccipital approach in relation to the tumor attachment of cerebellopontine angle meningiomas as well as postoperative complications related to venous occlusion. Forty-three patients with cerebellopontine angle meningiomas were analyzed retrospectively. Based on the operative findings, the tumors were classified into four subtypes: the petroclival type, tentorial type, anterior petrous type, and posterior petrous type. According to a previous anatomical report, the superior petrosal veins were divided into three groups: Type I which emptied into the superior petrosal sinus above and lateral to the internal acoustic meatus, Type II which emptied between the lateral limit of the trigeminal nerve at Meckel's cave and the medial limit of the facial nerve at the internal acoustic meatus, and Type III which emptied into the superior petrosal sinus above and medial to Meckel's cave. In both the petroclival and anterior petrous types, the most common vein was Type III which is the ideal vein for a retrosigmoid approach. In contrast, the Type II vein which is at high risk of being sacrificed during a suprameatal approach procedure was most frequent in posterior petrous type, in which the superior petrosal vein was not largely an obstacle. Intraoperative sacrificing of veins was associated with a significantly higher rate of venous-related phenomena, while venous complications occurred even in cases where the superior petrosal vein was absent or compressed by the tumor. The variation in the superior petrosal vein appeared to differ among the tumor attachment subtypes, which could permit a satisfactory surgical exposure without dividing the superior petrosal vein. In cases where the superior petrosal vein was previously occluded, other bridging veins could correspond with implications for the crucial venous drainage system, and should thus be identified and protected whenever possible.
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Neoplasias Cerebelosas/cirugía , Ángulo Pontocerebeloso/anatomía & histología , Venas Cerebrales/anatomía & histología , Neoplasias Meníngeas/cirugía , Meningioma/cirugía , Adolescente , Adulto , Anciano , Neoplasias Cerebelosas/irrigación sanguínea , Neoplasias Cerebelosas/patología , Ángulo Pontocerebeloso/cirugía , Venas Cerebrales/cirugía , Nervio Facial/anatomía & histología , Nervio Facial/cirugía , Femenino , Humanos , Masculino , Neoplasias Meníngeas/irrigación sanguínea , Neoplasias Meníngeas/patología , Meningioma/irrigación sanguínea , Meningioma/patología , Persona de Mediana Edad , Procedimientos Neuroquirúrgicos/métodos , Hueso Petroso/anatomía & histología , Hueso Petroso/cirugía , Estudios Retrospectivos , Adulto JovenRESUMEN
Transient ischemic attack (TIA) is a major complication in patients with carotid artery stenosis. Patients with severe stenosis sometimes complain of orthostatic dizziness, such as syncope. The purpose of this study was to examine the usefulness of near-infrared spectroscopy (NIRS) for evaluating cerebral circulation in patients with carotid artery stenosis during head-up tilt test (HUTT). Fourteen patients with carotid artery stenosis and nine normal control subjects participated. In addition to blood pressure monitoring, hemoglobin (Hb) values (oxy-Hb, deoxy-Hb, and total Hb) were recorded by a wearable NIRS instrument with a high time resolution during HUTT. Oxy-Hb, which decreased initially when the test table was elevated, subsequently increased in normal volunteers and patients with carotid artery stenosis and did not differ significantly between the two groups. However, the oxy-Hb reduction in the carotid artery stenosis group (-0.02 ± 0.03 a.u.) at 30 s after elevation of the table was significantly larger than in the normal group (0.02 ± 0.02 a.u., P < 0.01). Our results indicate that oxy-Hb reduction in patients with carotid artery stenosis may be related to orthostatic dizziness. We concluded that NIRS monitoring is useful for evaluating cerebral autoregulation in patients with severe carotid artery stenosis.