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1.
Neurology ; 102(5): e209134, 2024 Mar 12.
Artigo em Inglês | MEDLINE | ID: mdl-38350044

RESUMO

BACKGROUND AND OBJECTIVES: EEG and MRI features are independently associated with pediatric cardiac arrest (CA) outcomes, but it is unclear whether their combination improves outcome prediction. We aimed to assess the association of early EEG background category with MRI ischemia after pediatric CA and determine whether addition of MRI ischemia to EEG background features and clinical variables improves short-term outcome prediction. METHODS: This was a single-center retrospective cohort study of pediatric CA with EEG initiated ≤24 hours and MRI obtained ≤7 days of return of spontaneous circulation. Initial EEG background was categorized as normal, slow/disorganized, discontinuous/burst-suppression, or attenuated-featureless. MRI ischemia was defined as percentage of brain tissue with apparent diffusion coefficient (ADC) <650 × 10-6 mm2/s and categorized as high (≥10%) or low (<10%). Outcomes were mortality and unfavorable neurologic outcome (Pediatric Cerebral Performance Category increase ≥1 from baseline resulting in ICU discharge score ≥3). The Kruskal-Wallis test evaluated the association of EEG with MRI. Area under the receiver operating characteristic (AUROC) curve evaluated predictive accuracy. Logistic regression and likelihood ratio tests assessed multivariable outcome prediction. RESULTS: We evaluated 90 individuals. EEG background was normal in 16 (18%), slow/disorganized in 42 (47%), discontinuous/burst-suppressed in 12 (13%), and attenuated-featureless in 20 (22%) individuals. The median percentage of MRI ischemia was 5% (interquartile range 1-18); 32 (36%) individuals had high MRI ischemia burden. Twenty-eight (31%) individuals died, and 58 (64%) had unfavorable neurologic outcome. Worse EEG background category was associated with more MRI ischemia (p < 0.001). The combination of EEG background and MRI ischemia burden had higher predictive accuracy than EEG alone (AUROC: mortality: 0.92 vs 0.87, p = 0.03) or MRI alone (AUROC: mortality: 0.92 vs 0.84, p = 0.02; unfavorable: 0.83 vs 0.73, p < 0.01). Addition of percentage of MRI ischemia to clinical variables and EEG background category improved prediction for mortality (χ2 = 19.1, p < 0.001) and unfavorable neurologic outcome (χ2 = 4.8, p = 0.03) and achieved high predictive accuracy (AUROC: mortality: 0.97; unfavorable: 0.92). DISCUSSION: Early EEG background category was associated with MRI ischemia after pediatric CA. Combining EEG and MRI data yielded higher outcome predictive accuracy than either modality alone. The addition of MRI ischemia to clinical variables and EEG background improved short-term outcome prediction.


Assuntos
Parada Cardíaca , Humanos , Criança , Estudos Retrospectivos , Parada Cardíaca/complicações , Parada Cardíaca/terapia , Imageamento por Ressonância Magnética , Prognóstico , Imagem de Difusão por Ressonância Magnética/métodos , Neuroimagem , Eletroencefalografia/métodos , Espectroscopia de Ressonância Magnética , Isquemia/complicações
2.
Resuscitation ; 196: 110128, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38280508

RESUMO

AIM: Cerebral blood flow (CBF) is dysregulated after cardiac arrest. It is unknown if post-arrest CBF is associated with outcome. We aimed to determine the association of CBF derived from arterial spin labelling (ASL) MRI with outcome after pediatric cardiac arrest. METHODS: Retrospective observational study of patients ≤18 years who had a clinically obtained brain MRI within 7 days of cardiac arrest between June 2005 and December 2019. Primary outcome was unfavorable neurologic status: change in Pediatric Cerebral Performance Category (PCPC) ≥1 from pre-arrest that resulted in hospital discharge PCPC 3-6. We measured CBF in whole brain and regions of interest (ROIs) including frontal, parietal, and temporal cortex, caudate, putamen, thalamus, and brainstem using pulsed ASL. We compared CBF between outcome groups using Wilcoxon Rank-Sum and performed logistic regression to associate each region's CBF with outcome, accounting for age, sex, and time between arrest and MRI. RESULTS: Forty-eight patients were analyzed (median age 2.8 [IQR 0.95, 8.8] years, 65% male). Sixty-nine percent had unfavorable outcome. Time from arrest to MRI was 4 [3,5] days and similar between outcome groups (p = 0.39). Whole brain median CBF was greater for unfavorable compared to favorable groups (28.3 [20.9,33.0] vs. 19.6 [15.3,23.1] ml/100 g/min, p = 0.007), as was CBF in individual ROIs. Greater CBF in the whole brain and individual ROIs was associated with higher odds of unfavorable outcome after controlling for age, sex, and days from arrest to MRI (aOR for whole brain 19.08 [95% CI 1.94, 187.41]). CONCLUSION: CBF measured 3-5 days after pediatric cardiac arrest by ASL MRI was independently associated with unfavorable outcome.


Assuntos
Parada Cardíaca , Imageamento por Ressonância Magnética , Humanos , Criança , Masculino , Pré-Escolar , Feminino , Marcadores de Spin , Imageamento por Ressonância Magnética/métodos , Parada Cardíaca/terapia , Encéfalo/diagnóstico por imagem , Circulação Cerebrovascular/fisiologia
3.
J Electrocardiol ; 83: 4-11, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38181483

RESUMO

BACKGROUND: Diagnosis of left circumflex artery (LCx) myocardial infarctions via 12­lead electrocardiogram (ECG) has posed a challenge to healthcare professionals for many years. METHODS AND RESULTS: A retrospective observational study was performed to analyze patients admitted with myocardial infarction. The study used electronic medical records and specific ICD-10 codes to identify eligible patients, resulting in 2032 encounters. After independent adjudication of cardiac biomarkers, coronary angiography, and electrocardiographic changes, a final patient population of 58 encounters with acute occlusion myocardial infarction (OMI) with a culprit LCx lesion was established. OMI was defined as a lesion with either thrombolysis in myocardial infarction flow (TIMI) 0-2 or TIMI 3 with Troponin I > 1 ng/mL (Reference range 0.00-0.03 ng/mL). ECGs of these patients were then independently evaluated and grouped into 8 different classifications based on the presence or absence of ST elevation and/or depression in corresponding leads. ECG patterns and anatomical characteristics (proximal or distal to the first obtuse marginal artery) of the LCx lesions were then correlated. The appropriateness of triage and delay in reperfusion therapy were also assessed. Those with a left dominant or codominant circulation, and with LCx lesions proximal to the first obtuse marginal artery, were more likely to present with no or subtle ST-segment changes that led to delays in reperfusion therapy. CONCLUSIONS: Patients with left or codominant coronary artery circulation, with OMI proximal to the first obtuse marginal artery, may be less likely to have "classic" findings of ST-segment elevation on ECG due to cancellation forces in the limb leads.


Assuntos
Vasos Coronários , Infarto do Miocárdio , Humanos , Vasos Coronários/patologia , Eletrocardiografia , Infarto do Miocárdio/terapia , Angiografia Coronária , Estudos Retrospectivos
4.
J Cardiovasc Dev Dis ; 10(9)2023 Sep 06.
Artigo em Inglês | MEDLINE | ID: mdl-37754810

RESUMO

Dramatic advances in the management of congenital heart disease (CHD) have improved survival to adulthood from less than 10% in the 1960s to over 90% in the current era, such that adult CHD (ACHD) patients now outnumber their pediatric counterparts. ACHD patients demonstrate domain-specific neurocognitive deficits associated with reduced quality of life that include deficits in educational attainment and social interaction. Our hypothesis is that ACHD patients exhibit vascular brain injury and structural/physiological brain alterations that are predictive of specific neurocognitive deficits modified by behavioral and environmental enrichment proxies of cognitive reserve (e.g., level of education and lifestyle/social habits). This technical note describes an ancillary study to the National Heart, Lung, and Blood Institute (NHLBI)-funded Pediatric Heart Network (PHN) "Multi-Institutional Neurocognitive Discovery Study (MINDS) in Adult Congenital Heart Disease (ACHD)". Leveraging clinical, neuropsychological, and biospecimen data from the parent study, our study will provide structural-physiological correlates of neurocognitive outcomes, representing the first multi-center neuroimaging initiative to be performed in ACHD patients. Limitations of the study include recruitment challenges inherent to an ancillary study, implantable cardiac devices, and harmonization of neuroimaging biomarkers. Results from this research will help shape the care of ACHD patients and further our understanding of the interplay between brain injury and cognitive reserve.

5.
medRxiv ; 2023 Apr 17.
Artigo em Inglês | MEDLINE | ID: mdl-37131744

RESUMO

Patients with hypoplastic left heart syndrome who have been palliated with the Fontan procedure are at risk for adverse neurodevelopmental outcomes, lower quality of life, and reduced employability. We describe the methods (including quality assurance and quality control protocols) and challenges of a multi-center observational ancillary study, SVRIII (Single Ventricle Reconstruction Trial) Brain Connectome. Our original goal was to obtain advanced neuroimaging (Diffusion Tensor Imaging and Resting-BOLD) in 140 SVR III participants and 100 healthy controls for brain connectome analyses. Linear regression and mediation statistical methods will be used to analyze associations of brain connectome measures with neurocognitive measures and clinical risk factors. Initial recruitment challenges occurred related to difficulties with: 1) coordinating brain MRI for participants already undergoing extensive testing in the parent study, and 2) recruiting healthy control subjects. The COVID-19 pandemic negatively affected enrollment late in the study. Enrollment challenges were addressed by 1) adding additional study sites, 2) increasing the frequency of meetings with site coordinators and 3) developing additional healthy control recruitment strategies, including using research registries and advertising the study to community-based groups. Technical challenges that emerged early in the study were related to the acquisition, harmonization, and transfer of neuroimages. These hurdles were successfully overcome with protocol modifications and frequent site visits that involved human and synthetic phantoms. Trial registration number: ClinicalTrials.gov Registration Number: NCT02692443.

6.
Diagnostics (Basel) ; 13(9)2023 Apr 30.
Artigo em Inglês | MEDLINE | ID: mdl-37174995

RESUMO

Patients with hypoplastic left heart syndrome who have been palliated with the Fontan procedure are at risk for adverse neurodevelopmental outcomes, lower quality of life, and reduced employability. We describe the methods (including quality assurance and quality control protocols) and challenges of a multi-center observational ancillary study, SVRIII (Single Ventricle Reconstruction Trial) Brain Connectome. Our original goal was to obtain advanced neuroimaging (Diffusion Tensor Imaging and Resting-BOLD) in 140 SVR III participants and 100 healthy controls for brain connectome analyses. Linear regression and mediation statistical methods will be used to analyze associations of brain connectome measures with neurocognitive measures and clinical risk factors. Initial recruitment challenges occurred that were related to difficulties with: (1) coordinating brain MRI for participants already undergoing extensive testing in the parent study, and (2) recruiting healthy control subjects. The COVID-19 pandemic negatively affected enrollment late in the study. Enrollment challenges were addressed by: (1) adding additional study sites, (2) increasing the frequency of meetings with site coordinators, and (3) developing additional healthy control recruitment strategies, including using research registries and advertising the study to community-based groups. Technical challenges that emerged early in the study were related to the acquisition, harmonization, and transfer of neuroimages. These hurdles were successfully overcome with protocol modifications and frequent site visits that involved human and synthetic phantoms.

7.
Front Psychiatry ; 14: 1057221, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37252131

RESUMO

Introduction: The M50 electrophysiological auditory evoked response time can be measured at the superior temporal gyrus with magnetoencephalography (MEG) and its latency is related to the conduction velocity of auditory input passing from ear to auditory cortex. In children with autism spectrum disorder (ASD) and certain genetic disorders such as XYY syndrome, the auditory M50 latency has been observed to be elongated (slowed). Methods: The goal of this study is to use neuroimaging (diffusion MR and GABA MRS) measures to predict auditory conduction velocity in typically developing (TD) children and children with autism ASD and XYY syndrome. Results: Non-linear TD support vector regression modeling methods accounted for considerably more M50 latency variance than linear models, likely due to the non-linear dependence on neuroimaging factors such as GABA MRS. While SVR models accounted for ~80% of the M50 latency variance in TD and the genetically homogenous XYY syndrome, a similar approach only accounted for ~20% of the M50 latency variance in ASD, implicating the insufficiency of diffusion MR, GABA MRS, and age factors alone. Biologically based stratification of ASD was performed by assessing the conformance of the ASD population to the TD SVR model and identifying a sub-population of children with unexpectedly long M50 latency. Discussion: Multimodal integration of neuroimaging data can help build a mechanistic understanding of brain connectivity. The unexplained M50 latency variance in ASD motivates future hypothesis generation and testing of other contributing biological factors.

8.
J Autism Dev Disord ; 2023 Mar 17.
Artigo em Inglês | MEDLINE | ID: mdl-36932271

RESUMO

Resting-state alpha brain rhythms provide a foundation for basic as well as higher-order brain processes. Research suggests atypical maturation of the peak frequency of resting-state alpha activity (= PAF) in autism spectrum disorder (ASD). The present study examined resting-state alpha activity in young school-aged children, obtaining magnetoencephalographic (MEG) eyes-closed resting-state data from 47 typically developing (TD) males and 45 ASD males 6.0 to 9.3 years old. Results confirmed a higher PAF in ASD versus TD, and demonstrated that alpha power differences between groups were linked to the shift of PAF in ASD. Additionally, a higher PAF was associated with better cognitive performance in TD but not ASD. Finding thus suggested functional consequences of group differences in resting-state alpha activity.

9.
J Autism Dev Disord ; 53(10): 4076-4089, 2023 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-35960416

RESUMO

Maturation of auditory cortex neural encoding processes was assessed in children with typical development (TD) and autism. Children 6-9 years old were enrolled at Time 1 (T1), with follow-up data obtained ~ 18 months later at Time 2 (T2), and ~ 36 months later at Time 3 (T3). Findings suggested an initial period of rapid auditory cortex maturation in autism, earlier than TD (prior to and surrounding the T1 exam), followed by a period of faster maturation in TD than autism (T1-T3). As a result of group maturation differences, post-stimulus group differences were observed at T1 but not T3. In contrast, stronger pre-stimulus activity in autism than TD was found at all time points, indicating this brain measure is stable across time.


Assuntos
Córtex Auditivo , Transtorno do Espectro Autista , Transtorno Autístico , Humanos , Criança , Pré-Escolar , Potenciais Evocados Auditivos , Estimulação Acústica , Magnetoencefalografia
10.
J Am Coll Health ; 71(1): 162-171, 2023 01.
Artigo em Inglês | MEDLINE | ID: mdl-33577437

RESUMO

Objective: Graduate student mental health is a growing concern and the need for interventions is well-documented. This manuscript outlines an Acceptance and Commitment Therapy group treatment for graduate students intended to promote psychological flexibility through the cultivation of six processes: contact with the present moment (mindfulness), freely chosen life direction (values), distance from thoughts (defusion), nonjudgmental acknowledgement of one's internal experiences (acceptance), meta-awareness of one's own experiences (self-as-context), and ongoing patterns of behavior in the service of values (committed action). Participants: The treatment was delivered to graduate students across academic disciplines with variable psychological concerns over several semesters. Method: Graduate students completed measures of preliminary acceptability. Results: Clients perceived the intervention positively and believed they benefited from participating. Conclusion: Treatment evaluation information support the social validity and acceptability of the treatment and justify future studies assessing treatment efficacy and effectiveness.


Assuntos
Terapia de Aceitação e Compromisso , Atenção Plena , Humanos , Estudantes , Universidades , Resultado do Tratamento
12.
Neurology ; 2022 Aug 26.
Artigo em Inglês | MEDLINE | ID: mdl-36028319

RESUMO

BACKGROUND AND OBJECTIVES: Diffusion magnetic resonance imaging (MRI) can quantify extent of hypoxic-ischemic brain injury after cardiac arrest. Our objective was to determine the association between adult-derived threshold of apparent diffusion coefficient (ADC) <650x10-6mm2/s in >10% of brain tissue and unfavorable outcome after pediatric cardiac arrest. Since ADC decreases exponentially as a function of increasing age, we determined association 1) having >10% of brain tissue below a novel age-dependent ADC threshold, and 2) age-normalized whole brain mean ADC and unfavorable outcome. METHODS: Retrospective study of patients ≤18 years old who had cardiac arrest and a clinically obtained brain MRI within 7 days. Primary outcome was unfavorable neurologic status at hospital discharge based on Pediatric Cerebral Performance Category (PCPC) score. ADC images were extracted from three-direction diffusion imaging. We determined whether each patient had >10% of voxels with ADC below prespecified thresholds. We computed whole brain mean ADC for each patient. RESULTS: One-hundred-thirty-four patients were analyzed. Patients with ADC <650x10-6mm2/s in >10% of voxels had 15 times higher odds (95%CI 5, 65) of unfavorable outcome compared to patients with ADC <650x10-6mm2/s (AUROC 0.72 [95%CI 0.63, 0.80]). This ADC criteria had a sensitivity and specificity of 0.49 and 0.94, and positive and negative predictive values of 0.93 and 0.52 for unfavorable outcome. The age-dependent ADC threshold that yielded optimal sensitivity and specificity for unfavorable outcome was <300x10-6mm2/s below each patient's predicted whole brain mean ADC. The sensitivity, specificity, positive and negative predictive values for this ADC threshold were 0.53, 0.96, 0.96, and 0.54, respectively (OR: 26.4 [95%CI 7.5, 168.3]; AUROC 0.74 [95%CI 0.66, 0.83]). Lower age-normalized whole brain mean ADC was also associated with unfavorable outcome (OR 0.42 [0.24, 0.64], AUROC 0.76 [95%CI 0.66, 0.82]). DISCUSSION: Quantitative diffusion thresholds on MRI within 7 days after cardiac arrest were associated with unfavorable outcome in children. Age-independent ADC threshold was highly specific for predicting unfavorable outcome. However, specificity and sensitivity increased when using age-dependent ADC thresholds. Age-dependent ADC thresholds may improve prognostic accuracy and require further investigation in larger cohorts. CLASSIFICATION OF EVIDENCE: This study provides Class III evidence that quantitative diffusion-weighted imaging (DWI) within 7 days post-arrest can predict an unfavorable clinical outcome in children.

13.
Int J Psychophysiol ; 178: 51-59, 2022 08.
Artigo em Inglês | MEDLINE | ID: mdl-35718287

RESUMO

BACKGROUND: At rest, 8 to 12 Hz alpha rhythms are the dominant rhythm in the brain, with a common peak alpha frequency (PAF = the frequency at which alpha generators show maximum power) observed across brain regions. Although a common PAF across brain regions should result in high between-region connectivity, especially connectivity measures assessing the phase-similarity between alpha generators, high inter-regional alpha connectivity has not been observed. The present study was conducted as an initial step toward identifying mechanisms that allow brain regions to maintain functional independence in the presence of a common PAF. METHODS: MEG data were obtained from 16 healthy control male adults (mean age = 24 years; range 21 to 30 years). A task requiring participants to alternate between a 10 s eyes-closed condition and a 5 s eyes-open condition was used to drive parietal-occipital alpha generators, with the 10 s eyes-closed condition eliciting large-amplitude alpha activity and thus providing alpha measures with good signal-to-noise ratio for source localization. Alpha source-space measures were obtained using Vector-based Spatial-Temporal Analysis using L1-minimum-norm. In each participant, the four strongest parietal-occipital alpha generators were identified. Connectivity between sources was assessed via a measure of phase-based connectivity called inter-site phase clustering (ISPC). RESULTS: Intra-class correlations (ICC) showed very high similarity in the average PAF (=computed using all eyes-closed data) between the four alpha sources (ICC single measure = 0.88, p < 0.001). Despite a common average PAF, across participants, significant ISPC was often observed no more than that expected by chance. Examination of the alpha time course data indicated that low ISPC was often due to instantaneous changes in alpha phase (phase slips). ISPC analyses removing data with phase slips indicated that low ISPC was also due to slight continuous changes in the alpha frequency, with frequency drift more likely in non-significant than significant ISPC trials. CONCLUSIONS: The present exploratory effort suggested two processes underlying the lack of observed inter-regional alpha phase coherence that may help maintain regional functional independence even in the presence of a common PAF. In particular, although the alpha generators were observed to oscillate at the same rate on average, across time each alpha generator oscillated a little slower or faster, and about every one and a half seconds an alpha generator abruptly lost the beat. Because of this, functional independence among alpha generators (and thus brain regions) was the rule rather than the exception. Studies replicating these processes that allow brain regions to maintain functional independence, using different source localization methods and in different conditions (e.g., a true resting state), are warranted. IMPACT STATEMENT: Using source localization to measure parietal-occipital alpha generator activity, two properties that limit between-region alpha functional connectivity are proposed. In particular, a model of alpha generator activity is offered where via transient phase slips occurring approximately every 1.5 s, as well as slight non-stationarity in the alpha frequency, brain regions retain a common alpha frequency while also maintaining regional identity and presumably functionality. Findings also suggest novel markers for use in studies examining changes in alpha activity across maturation as well as in studies examining alpha activity in patient populations where alpha abnormalities have been reported.


Assuntos
Encéfalo , Magnetoencefalografia , Adulto , Ritmo alfa/fisiologia , Encéfalo/fisiologia , Mapeamento Encefálico/métodos , Olho , Humanos , Magnetoencefalografia/métodos , Masculino , Adulto Jovem
14.
J Intensive Care Med ; 37(4): 441-458, 2022 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33611981

RESUMO

Sarcoidosis is a systemic inflammatory disease defined by the presence of aberrant granulomas affecting various organs. Due to its multisystem involvement, care of patients with established sarcoidosis becomes challenging, especially in the intensive care setting. While the lungs are typically involved, extrapulmonary manifestations also occur either concurrently or exclusively within a significant proportion of patients, complicating diagnostic and management decisions. The scope of this review is to focus on what considerations are necessary in the evaluation and management of patients with known sarcoidosis and their associated complications within a cardiopulmonary and critical care perspective.


Assuntos
Sarcoidose , Cuidados Críticos , Granuloma/complicações , Humanos , Pulmão , Sarcoidose/complicações , Sarcoidose/diagnóstico , Sarcoidose/terapia
15.
J Autism Dev Disord ; 52(1): 103-112, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33629214

RESUMO

Associations between age, resting-state (RS) peak-alpha-frequency (PAF = frequency showing largest amplitude alpha activity), and thalamic volume (thalamus thought to modulate alpha activity) were examined to understand differences in RS alpha activity between children with autism spectrum disorder (ASD) and typically-developing children (TDC) noted in prior studies. RS MEG and structural-MRI data were obtained from 51 ASD and 70 TDC 6- to 18-year-old males. PAF and thalamic volume maturation were observed in TDC but not ASD. Although PAF was associated with right thalamic volume in TDC (R2 = 0.12, p = 0.01) but not ASD (R2 = 0.01, p = 0.35), this group difference was not large enough to reach significance. Findings thus showed unusual maturation of brain function and structure in ASD as well as an across-group thalamic contribution to alpha rhythms.


Assuntos
Transtorno do Espectro Autista , Adolescente , Encéfalo , Criança , Humanos , Imageamento por Ressonância Magnética , Masculino , Tálamo/diagnóstico por imagem
16.
Cureus ; 13(10): e19063, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34853768

RESUMO

Pediatric burns are a common and often devastating injury. Treatment, reconstruction, and rehabilitation are painful experiences. For some, the experience triggers post-traumatic stress disorder and/or a chronic pain syndrome. Given the role pain plays as a major secondary disease, it must be addressed to achieve optimal healing. Regional anesthesia has been used extensively to manage postoperative pain and reduce the need for opioids following other surgical procedures in children. However, regional anesthesia is not widely used in pediatric burn care. We present a descriptive, retrospective case series of 15 pediatric burn patients who received regional anesthesia as part of their intra-operative pain management. In our patient population, we saw low levels of anesthetic as well as opioid usage with well-controlled pain. In this cohort, 93% of patients scored a 0/10 on the Face, Legs, Activity, Cry and Consolability (FLACC) scale for pain by post-anesthesia care unit (PACU) discharge, with an average PACU stay of 70 minutes. Thirty-three percent of patients received no opioids, with the average opioid dose being 0.06mg/kg morphine equivalents. This case series serves to make clinicians aware of the feasibility of use and benefits of regional anesthesia in pediatric burn patients requiring operative repair.

17.
Neuroimage ; 241: 118430, 2021 11 01.
Artigo em Inglês | MEDLINE | ID: mdl-34314848

RESUMO

PURPOSE: Heating of gradient coils and passive shim components is a common cause of instability in the B0 field, especially when gradient intensive sequences are used. The aim of the study was to set a benchmark for typical drift encountered during MR spectroscopy (MRS) to assess the need for real-time field-frequency locking on MRI scanners by comparing field drift data from a large number of sites. METHOD: A standardized protocol was developed for 80 participating sites using 99 3T MR scanners from 3 major vendors. Phantom water signals were acquired before and after an EPI sequence. The protocol consisted of: minimal preparatory imaging; a short pre-fMRI PRESS; a ten-minute fMRI acquisition; and a long post-fMRI PRESS acquisition. Both pre- and post-fMRI PRESS were non-water suppressed. Real-time frequency stabilization/adjustment was switched off when appropriate. Sixty scanners repeated the protocol for a second dataset. In addition, a three-hour post-fMRI MRS acquisition was performed at one site to observe change of gradient temperature and drift rate. Spectral analysis was performed using MATLAB. Frequency drift in pre-fMRI PRESS data were compared with the first 5:20 minutes and the full 30:00 minutes of data after fMRI. Median (interquartile range) drifts were measured and showed in violin plot. Paired t-tests were performed to compare frequency drift pre- and post-fMRI. A simulated in vivo spectrum was generated using FID-A to visualize the effect of the observed frequency drifts. The simulated spectrum was convolved with the frequency trace for the most extreme cases. Impacts of frequency drifts on NAA and GABA were also simulated as a function of linear drift. Data from the repeated protocol were compared with the corresponding first dataset using Pearson's and intraclass correlation coefficients (ICC). RESULTS: Of the data collected from 99 scanners, 4 were excluded due to various reasons. Thus, data from 95 scanners were ultimately analyzed. For the first 5:20 min (64 transients), median (interquartile range) drift was 0.44 (1.29) Hz before fMRI and 0.83 (1.29) Hz after. This increased to 3.15 (4.02) Hz for the full 30 min (360 transients) run. Average drift rates were 0.29 Hz/min before fMRI and 0.43 Hz/min after. Paired t-tests indicated that drift increased after fMRI, as expected (p < 0.05). Simulated spectra convolved with the frequency drift showed that the intensity of the NAA singlet was reduced by up to 26%, 44 % and 18% for GE, Philips and Siemens scanners after fMRI, respectively. ICCs indicated good agreement between datasets acquired on separate days. The single site long acquisition showed drift rate was reduced to 0.03 Hz/min approximately three hours after fMRI. DISCUSSION: This study analyzed frequency drift data from 95 3T MRI scanners. Median levels of drift were relatively low (5-min average under 1 Hz), but the most extreme cases suffered from higher levels of drift. The extent of drift varied across scanners which both linear and nonlinear drifts were observed.


Assuntos
Encéfalo/diagnóstico por imagem , Encéfalo/metabolismo , Análise de Dados , Bases de Dados Factuais/normas , Imageamento por Ressonância Magnética/normas , Espectroscopia de Ressonância Magnética/normas , Humanos , Imageamento por Ressonância Magnética/métodos , Espectroscopia de Ressonância Magnética/métodos
19.
BMJ Open ; 11(4): e043852, 2021 04 22.
Artigo em Inglês | MEDLINE | ID: mdl-33888528

RESUMO

INTRODUCTION: MRI and MR spectroscopy (MRS) provide early biomarkers of brain injury and treatment response in neonates with hypoxic-ischaemic encephalopathy). Still, there are challenges to incorporating neuroimaging biomarkers into multisite randomised controlled trials. In this paper, we provide the rationale for incorporating MRI and MRS biomarkers into the multisite, phase III high-dose erythropoietin for asphyxia and encephalopathy (HEAL) Trial, the MRI/S protocol and describe the strategies used for harmonisation across multiple MRI platforms. METHODS AND ANALYSIS: Neonates with moderate or severe encephalopathy enrolled in the multisite HEAL trial undergo MRI and MRS between 96 and 144 hours of age using standardised neuroimaging protocols. MRI and MRS data are processed centrally and used to determine a brain injury score and quantitative measures of lactate and n-acetylaspartate. Harmonisation is achieved through standardisation-thereby reducing intrasite and intersite variance, real-time quality assurance monitoring and phantom scans. ETHICS AND DISSEMINATION: IRB approval was obtained at each participating site and written consent obtained from parents prior to participation in HEAL. Additional oversight is provided by an National Institutes of Health-appointed data safety monitoring board and medical monitor. TRIAL REGISTRATION NUMBER: NCT02811263; Pre-result.


Assuntos
Eritropoetina , Hipóxia-Isquemia Encefálica , Asfixia , Biomarcadores , Protocolos de Ensaio Clínico como Assunto , Humanos , Hipóxia-Isquemia Encefálica/diagnóstico por imagem , Hipóxia-Isquemia Encefálica/tratamento farmacológico , Recém-Nascido , Estudos Multicêntricos como Assunto , Neuroimagem
20.
Eur J Psychol ; 17(1): 53-69, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33737974

RESUMO

Previous research demonstrates that writing about life's difficult moments benefits the writer cognitively and emotionally. However, it is unclear whether the benefits of writing are specific to the event written about or whether the benefits are global. This study was designed to address this issue. Participants were 120 undergraduate students who had experienced at least two difficult life events. Participants were randomly assigned into experimental and control groups. Experimental participants wrote about one of these difficult events and control participants wrote about an interesting life event of their choosing. Experimental participants reported their positive and negative emotions as well as their cognitive avoidance and intrusion concerning the event written about and another event not written about. Control participants reported their emotions and cognitions concerning two difficult life events. All participants also reported their general distress. These assessments were done immediately after writing and one week later. The results indicated that experimental participants were emotionally stronger, less upset, and less cognitively avoidant about the particular difficult life event they wrote about compared to an event they did not write about. Similar comparisons between ratings of a written-about and a not-written-about event were not significant for passion, fear, and cognitive intrusion. There was evidence for a possible indirect effect of writing on general distress through changes in event-specific cognitions and emotions. Discussion of these results focuses on how writing may specifically help change a writer's feelings and thoughts about a particular situation.

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