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1.
AJNR Am J Neuroradiol ; 43(4): 603-610, 2022 04.
Artigo em Inglês | MEDLINE | ID: mdl-35361575

RESUMO

BACKGROUND AND PURPOSE: Pediatric supratentorial tumors such as embryonal tumors, high-grade gliomas, and ependymomas are difficult to distinguish by histopathology and imaging because of overlapping features. We applied machine learning to uncover MR imaging-based radiomics phenotypes that can differentiate these tumor types. MATERIALS AND METHODS: Our retrospective cohort of 231 patients from 7 participating institutions had 50 embryonal tumors, 127 high-grade gliomas, and 54 ependymomas. For each tumor volume, we extracted 900 Image Biomarker Standardization Initiative-based PyRadiomics features from T2-weighted and gadolinium-enhanced T1-weighted images. A reduced feature set was obtained by sparse regression analysis and was used as input for 6 candidate classifier models. Training and test sets were randomly allocated from the total cohort in a 75:25 ratio. RESULTS: The final classifier model for embryonal tumor-versus-high-grade gliomas identified 23 features with an area under the curve of 0.98; the sensitivity, specificity, positive predictive value, negative predictive value, and accuracy were 0.85, 0.91, 0.79, 0.94, and 0.89, respectively. The classifier for embryonal tumor-versus-ependymomas identified 4 features with an area under the curve of 0.82; the sensitivity, specificity, positive predictive value, negative predictive value, and accuracy were 0.93, 0.69, 0.76, 0.90, and 0.81, respectively. The classifier for high-grade gliomas-versus-ependymomas identified 35 features with an area under the curve of 0.96; the sensitivity, specificity, positive predictive value, negative predictive value, and accuracy were 0.82, 0.94, 0.82, 0.94, and 0.91, respectively. CONCLUSIONS: In this multi-institutional study, we identified distinct radiomic phenotypes that distinguish pediatric supratentorial tumors, high-grade gliomas, and ependymomas with high accuracy. Incorporation of this technique in diagnostic algorithms can improve diagnosis, risk stratification, and treatment planning.


Assuntos
Neoplasias Encefálicas , Ependimoma , Glioma , Neoplasias Embrionárias de Células Germinativas , Tumores Neuroectodérmicos Primitivos , Neoplasias Supratentoriais , Neoplasias Encefálicas/genética , Criança , Ependimoma/diagnóstico por imagem , Glioma/genética , Humanos , Imageamento por Ressonância Magnética/métodos , Neoplasias Embrionárias de Células Germinativas/diagnóstico por imagem , Estudos Retrospectivos , Neoplasias Supratentoriais/diagnóstico por imagem
2.
AJNR Am J Neuroradiol ; 42(9): 1702-1708, 2021 09.
Artigo em Inglês | MEDLINE | ID: mdl-34266866

RESUMO

BACKGROUND AND PURPOSE: Atypical teratoid/rhabdoid tumors and medulloblastomas have similar imaging and histologic features but distinctly different outcomes. We hypothesized that they could be distinguished by MR imaging-based radiomic phenotypes. MATERIALS AND METHODS: We retrospectively assembled T2-weighted and gadolinium-enhanced T1-weighted images of 48 posterior fossa atypical teratoid/rhabdoid tumors and 96 match-paired medulloblastomas from 7 institutions. Using a holdout test set, we measured the performance of 6 candidate classifier models using 6 imaging features derived by sparse regression of 900 T2WI and 900 T1WI Imaging Biomarker Standardization Initiative-based radiomics features. RESULTS: From the originally extracted 1800 total Imaging Biomarker Standardization Initiative-based features, sparse regression consistently reduced the feature set to 1 from T1WI and 5 from T2WI. Among classifier models, logistic regression performed with the highest AUC of 0.86, with sensitivity, specificity, accuracy, and F1 scores of 0.80, 0.82, 0.81, and 0.85, respectively. The top 3 important Imaging Biomarker Standardization Initiative features, by decreasing order of relative contribution, included voxel intensity at the 90th percentile, inverse difference moment normalized, and kurtosis-all from T2WI. CONCLUSIONS: Six quantitative signatures of image intensity, texture, and morphology distinguish atypical teratoid/rhabdoid tumors from medulloblastomas with high prediction performance across different machine learning strategies. Use of this technique for preoperative diagnosis of atypical teratoid/rhabdoid tumors could significantly inform therapeutic strategies and patient care discussions.


Assuntos
Neoplasias Cerebelares , Meduloblastoma , Tumor Rabdoide , Humanos , Imageamento por Ressonância Magnética , Meduloblastoma/diagnóstico por imagem , Fenótipo , Estudos Retrospectivos , Tumor Rabdoide/diagnóstico por imagem
3.
Br Med Bull ; 138(1): 41-57, 2021 06 10.
Artigo em Inglês | MEDLINE | ID: mdl-33884400

RESUMO

INTRODUCTION: This is an overall review on mindfulness-based interventions (MBIs). SOURCES OF DATA: We identified studies in PubMed, EMBASE, CINAHL, PsycINFO, AMED, Web of Science and Google Scholar using keywords including 'mindfulness', 'meditation', and 'review', 'meta-analysis' or their variations. AREAS OF AGREEMENT: MBIs are effective for improving many biopsychosocial conditions, including depression, anxiety, stress, insomnia, addiction, psychosis, pain, hypertension, weight control, cancer-related symptoms and prosocial behaviours. It is found to be beneficial in the healthcare settings, in schools and workplace but further research is warranted to look into its efficacy on different problems. MBIs are relatively safe, but ethical aspects should be considered. Mechanisms are suggested in both empirical and neurophysiological findings. Cost-effectiveness is found in treating some health conditions. AREAS OF CONTROVERSY: Inconclusive or only preliminary evidence on the effects of MBIs on PTSD, ADHD, ASD, eating disorders, loneliness and physical symptoms of cardiovascular diseases, diabetes, and respiratory conditions. Furthermore, some beneficial effects are not confirmed in subgroup populations. Cost-effectiveness is yet to confirm for many health conditions and populations. GROWING POINTS: Many mindfulness systematic reviews and meta-analyses indicate low quality of included studies, hence high-quality studies with adequate sample size and longer follow-up period are needed. AREAS TIMELY FOR DEVELOPING RESEARCH: More research is needed on online mindfulness trainings and interventions to improve biopsychosocial health during the COVID-19 pandemic; Deeper understanding of the mechanisms of MBIs integrating both empirical and neurophysiological findings; Long-term compliance and effects of MBIs; and development of mindfulness plus (mindfulness+) or personalized mindfulness programs to elevate the effectiveness for different purposes.


Assuntos
COVID-19/psicologia , COVID-19/terapia , Atenção Plena , COVID-19/epidemiologia , Humanos
4.
Eur Ann Otorhinolaryngol Head Neck Dis ; 138(4): 275-277, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-33184013

RESUMO

INTRODUCTION: Organised hematoma (OH) in the para-nasal sinus and nasal cavity is a rare, non-neoplastic, benign disease which can be locally aggressive. In clinical practice, OH is easily misdiagnosed as malignancy and over-treated. CASE SUMMARY: These patients with OH had a common history of malignant neoplasms post-radiotherapy, including two cases of nasopharyngeal carcinoma and one case of tonsil cancer with jaw osteosarcoma. All of the patients presented with symptoms of epistaxis and blood-tinged rhinorrhea. All of the patients received endoscopic endonasal surgery under navigation. DISCUSSION: All of the patients had a good recovery after surgery. There's no recurrence after follow-up at 6 months. We therefore hypothesised that radiotherapy could be a cause of the OH. Although OH is uncommon and difficult to diagnose, a history of malignancy and imaging features with appropriate treatment are key.


Assuntos
Neoplasias Nasofaríngeas , Neoplasias Nasais , Hematoma/etiologia , Humanos , Neoplasias Nasofaríngeas/radioterapia , Recidiva Local de Neoplasia , Neoplasias Nasais/diagnóstico , Estudos Retrospectivos
5.
AJNR Am J Neuroradiol ; 41(9): 1718-1725, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32816765

RESUMO

BACKGROUND AND PURPOSE: Posterior fossa tumors are the most common pediatric brain tumors. MR imaging is key to tumor detection, diagnosis, and therapy guidance. We sought to develop an MR imaging-based deep learning model for posterior fossa tumor detection and tumor pathology classification. MATERIALS AND METHODS: The study cohort comprised 617 children (median age, 92 months; 56% males) from 5 pediatric institutions with posterior fossa tumors: diffuse midline glioma of the pons (n = 122), medulloblastoma (n = 272), pilocytic astrocytoma (n = 135), and ependymoma (n = 88). There were 199 controls. Tumor histology served as ground truth except for diffuse midline glioma of the pons, which was primarily diagnosed by MR imaging. A modified ResNeXt-50-32x4d architecture served as the backbone for a multitask classifier model, using T2-weighted MRIs as input to detect the presence of tumor and predict tumor class. Deep learning model performance was compared against that of 4 radiologists. RESULTS: Model tumor detection accuracy exceeded an AUROC of 0.99 and was similar to that of 4 radiologists. Model tumor classification accuracy was 92% with an F1 score of 0.80. The model was most accurate at predicting diffuse midline glioma of the pons, followed by pilocytic astrocytoma and medulloblastoma. Ependymoma prediction was the least accurate. Tumor type classification accuracy and F1 score were higher than those of 2 of the 4 radiologists. CONCLUSIONS: We present a multi-institutional deep learning model for pediatric posterior fossa tumor detection and classification with the potential to augment and improve the accuracy of radiologic diagnosis.


Assuntos
Aprendizado Profundo , Interpretação de Imagem Assistida por Computador/métodos , Neoplasias Infratentoriais/classificação , Neoplasias Infratentoriais/diagnóstico por imagem , Adolescente , Adulto , Criança , Pré-Escolar , Feminino , Humanos , Lactente , Neoplasias Infratentoriais/patologia , Imageamento por Ressonância Magnética/métodos , Masculino , Adulto Jovem
6.
J Acoust Soc Am ; 146(3): 1580, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31590498

RESUMO

The acoustical insertion loss of asymmetrical balconies on high-rise buildings was studied experimentally using a 1:3 scaled down model in the present study. Four balcony forms featured by the presence of a full-height side-wall were included. A linear loudspeaker array was adopted as the sound source. The effects of source orientation and balcony elevation angle on the insertion loss and its spectral variation were examined. The position of the full-height side-wall relative to the sound source significantly affects the balcony insertion loss. It is observed that the maximum traffic noise amplification and attenuation are both ∼6 dBA. Results also suggest that the balustrade has no effect on the insertion loss spectral variation pattern, though the insertion loss magnitude could be much reduced without it in the presence of a short side-wall. This short side-wall determines the insertion loss spectral variation pattern. Significant sound amplification is found at frequencies of the odd order transverse modes, the longitudinal modes, and their coupled modes regardless of balcony form and elevation angle. It is also found that the major acoustic mode interactions are basically independent of source orientation for balconies without the short side-wall.

7.
BMC Genomics ; 19(1): 815, 2018 Nov 13.
Artigo em Inglês | MEDLINE | ID: mdl-30424733

RESUMO

BACKGROUND: The basidiomycete Phanerochaete carnosa is a white-rot species that has been mainly isolated from coniferous softwood. Given the particular recalcitrance of softwoods to bioconversion, we conducted a comparative transcriptomic analysis of P. carnosa following growth on wood powder from one softwood (spruce; Picea glauca) and one hardwood (aspen; Populus tremuloides). P. carnosa was grown on each substrate for over one month, and mycelia were harvested at five time points for total RNA sequencing. Residual wood powder was also analyzed for total sugar and lignin composition. RESULTS: Following a slightly longer lag phase of growth on spruce, radial expansion of the P. carnosa colony was similar on spruce and aspen. Consistent with this observation, the pattern of gene expression by P. carnosa on each substrate converged following the initial adaptation. On both substrates, highest transcript abundances were attributed to genes predicted to encode manganese peroxidases (MnP), along with auxiliary activities from carbohydrate-active enzyme (CAZy) families AA3 and AA5. In addition, a lytic polysaccharide monooxygenase from family AA9 was steadily expressed throughout growth on both substrates. P450 sequences from clans CPY52 and CYP64 accounted for 50% or more of the most highly expressed P450s, which were also the P450 clans that were expanded in the P. carnosa genome relative to other white-rot fungi. CONCLUSIONS: The inclusion of five growth points and two wood substrates was important to revealing differences in the expression profiles of specific sequences within large glycoside hydrolase families (e.g., GH5 and GH16), and permitted co-expression analyses that identified new targets for study, including non-catalytic proteins and proteins with unknown function.


Assuntos
Proteínas Fúngicas/genética , Regulação Fúngica da Expressão Gênica , Phanerochaete/genética , Picea/microbiologia , Populus/microbiologia , Transcriptoma , Madeira/microbiologia , Perfilação da Expressão Gênica , Phanerochaete/fisiologia
8.
J Nanosci Nanotechnol ; 18(10): 7281-7285, 2018 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-29954574

RESUMO

This paper analytically investigates the picosecond laser ablation of polymer. Laser-pulsed ablation is a well-established tool for polymer. However the ablation mechanism of laser processing for polymer has not been thoroughly understood yet. This study utilized a thermal transport model to analyze the relationship between the ablation rate and laser fluences. This model considered the energy balance at the decomposition interface as the ablation mechanisms and is applied to predict the laser-ablated depth of Acrylonitrile Butadiene Styrene/PolyVinyl Chloride (ABS/PVC). The calculated variation of the ablation rate with the logarithm of the laser fluence agrees with the measured data. The effects of material properties and processing parameters on the ablation depth per pulse are discussed for picosecond laser processing of ABS/PVC.

9.
Clin Radiol ; 72(10): 902.e13-902.e19, 2017 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-28545686

RESUMO

AIM: To evaluate spinal magnetic resonance imaging (MRI) examinations using a combination of two-dimensional (2D) and three-dimensional (3D) MRI sequences for diagnosis of drop metastases. MATERIALS AND METHODS: Fifty-five paediatric patients with primary brain tumours were evaluated for drop metastases at initial presentation using spinal MRI including sagittal 2D T1-weighted (W) contrast-enhanced (+C), axial 3D T1W+C volumetric interpolated breath-hold (VIBE), and sagittal 3D T2W SPACE (Sampling Perfection with Application optimised Contrasts using different flip angle Evolutions). RESULTS: The MRI false-negative rate was 4%, and cerebrospinal fluid (CSF) false-negative rate was 16% (p=0.07). The 3D T1W+C VIBE increased the number of drop metastases detected in 42% of patients. Drop metastases were more conspicuous in 25% of patients on 3D T2W SPACE. CONCLUSION: Spinal MRI examinations including 2D and 3D sequences demonstrate characteristics that may improve radiological diagnosis of drop metastases.


Assuntos
Neoplasias Encefálicas/patologia , Imageamento Tridimensional/métodos , Imageamento por Ressonância Magnética/métodos , Neoplasias Meníngeas/diagnóstico por imagem , Neoplasias Meníngeas/secundário , Adolescente , Criança , Pré-Escolar , Feminino , Humanos , Lactente , Masculino , Estudos Retrospectivos
10.
AJNR Am J Neuroradiol ; 38(4): 807-813, 2017 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-28183837

RESUMO

BACKGROUND AND PURPOSE: MR imaging with sedation is commonly used to detect intracranial traumatic pathology in the pediatric population. Our purpose was to compare nonsedated ultrafast MR imaging, noncontrast head CT, and standard MR imaging for the detection of intracranial trauma in patients with potential abusive head trauma. MATERIALS AND METHODS: A prospective study was performed in 24 pediatric patients who were evaluated for potential abusive head trauma. All patients received noncontrast head CT, ultrafast brain MR imaging without sedation, and standard MR imaging with general anesthesia or an immobilizer, sequentially. Two pediatric neuroradiologists independently reviewed each technique blinded to other modalities for intracranial trauma. We performed interreader agreement and consensus interpretation for standard MR imaging as the criterion standard. Diagnostic accuracy was calculated for ultrafast MR imaging, noncontrast head CT, and combined ultrafast MR imaging and noncontrast head CT. RESULTS: Interreader agreement was moderate for ultrafast MR imaging (κ = 0.42), substantial for noncontrast head CT (κ = 0.63), and nearly perfect for standard MR imaging (κ = 0.86). Forty-two percent of patients had discrepancies between ultrafast MR imaging and standard MR imaging, which included detection of subarachnoid hemorrhage and subdural hemorrhage. Sensitivity, specificity, and positive and negative predictive values were obtained for any traumatic pathology for each examination: ultrafast MR imaging (50%, 100%, 100%, 31%), noncontrast head CT (25%, 100%, 100%, 21%), and a combination of ultrafast MR imaging and noncontrast head CT (60%, 100%, 100%, 33%). Ultrafast MR imaging was more sensitive than noncontrast head CT for the detection of intraparenchymal hemorrhage (P = .03), and the combination of ultrafast MR imaging and noncontrast head CT was more sensitive than noncontrast head CT alone for intracranial trauma (P = .02). CONCLUSIONS: In abusive head trauma, ultrafast MR imaging, even combined with noncontrast head CT, demonstrated low sensitivity compared with standard MR imaging for intracranial traumatic pathology, which may limit its utility in this patient population.


Assuntos
Maus-Tratos Infantis , Traumatismos Craniocerebrais/diagnóstico por imagem , Imageamento por Ressonância Magnética/métodos , Anestesia Geral , Pré-Escolar , Traumatismos Craniocerebrais/epidemiologia , Feminino , Escala de Coma de Glasgow , Hematoma Subdural/diagnóstico por imagem , Humanos , Lactente , Masculino , Variações Dependentes do Observador , Valor Preditivo dos Testes , Prevalência , Estudos Prospectivos , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Hemorragia Subaracnóidea/diagnóstico por imagem , Tomografia Computadorizada por Raios X
11.
J Neurooncol ; 130(1): 141-148, 2016 10.
Artigo em Inglês | MEDLINE | ID: mdl-27438082

RESUMO

Cerebral radiation necrosis (CRN) is a toxicity of radiation therapy that can result in significant, potentially life-threatening neurologic deficits. Treatment for CRN has included surgical resection, corticosteroids, hyperbaric oxygen therapy (HBOT), and bevacizumab, but no consensus approach has been identified. We reviewed the available literature to evaluate efficacy of treatment approaches. Using methods specified in the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines when possible, we conducted searches of Ovid MEDLINE, Embase and Pubmed to identify studies reporting on outcomes for children (≤21 years old) with CRN. Eligible studies from 1990 to 2014 describing central nervous system (CNS) radiation necrosis with details of both treatment and outcomes were included. Eleven studies meeting criteria were identified. Of the nine studies with total patient denominators, 37 of 806 patients developed CRN (incidence = 4.6 %). Patients received treatment courses of steroids alone (n = 13), steroids with bevacizumab (n = 11) or HBOT (n = 12). Patients who failed to respond to steroids were more likely to be older than steroid-responsive patients (p = 0.009). With the exception of steroid-related adverse events, there was only one report of an adverse event (brainstem stroke) potentially attributable to intervention (bevacizumab). Those who received proton beam RT were both younger (p = 0.001) and had a shorter time to development of CRN (p = 0.079). The most common treatment following steroid initiation was addition of bevacizumab or HBOT, with good success and minimal toxicity. However, randomized controlled trials are needed to establish a definitive treatment algorithm that can be applied to children affected by CRN.


Assuntos
Córtex Cerebral/patologia , Necrose/etiologia , Necrose/terapia , Pediatria , Radioterapia/efeitos adversos , Bevacizumab/uso terapêutico , Neoplasias Encefálicas/radioterapia , Bases de Dados Bibliográficas/estatística & dados numéricos , Humanos , Esteroides/uso terapêutico
12.
AJNR Am J Neuroradiol ; 37(3): 544-51, 2016 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-26564438

RESUMO

BACKGROUND AND PURPOSE: The pattern of contrast leakage from DSC tissue signal intensity time curves have shown utility in distinguishing adult brain neoplasms, but has limited description in the literature for pediatric brain tumors. The purpose of this study is to evaluate the utility of grading pediatric brain tumors with this technique. MATERIALS AND METHODS: A retrospective review of tissue signal-intensity time curves from 63 pediatric brain tumors with preoperative DSC perfusion MR imaging was performed independently by 2 neuroradiologists. Tissue signal-intensity time curves were generated from ROIs placed in the highest perceived tumor relative CBV. The postbolus portion of the curve was independently classified as returning to baseline, continuing above baseline (T1-dominant contrast leakage), or failing to return to baseline (T2*-dominant contrast leakage). Interobserver agreement of curve classification was evaluated by using the Cohen κ. A consensus classification of curve type was obtained in discrepant cases, and the consensus classification was compared with tumor histology and World Health Organization grade. RESULTS: Tissue signal-intensity time curve classification concordance was 0.69 (95% CI, 0.54-0.84) overall and 0.79 (95% CI, 0.59-0.91) for a T1-dominant contrast leakage pattern. Twenty-five of 25 tumors with consensus T1-dominant contrast leakage were low-grade (positive predictive value, 1.0; 95% CI, 0.83-1.00). By comparison, tumors with consensus T2*-dominant contrast leakage or return to baseline were predominantly high-grade (10/15 and 15/23, respectively) with a high negative predictive value (1.0; 95% CI, 0.83-1.0). For pilomyxoid or pilocytic astrocytomas, a T1-dominant leak demonstrated high sensitivity (0.91; 95% CI, 0.70-0.98) and specificity (0.90, 95% CI, 0.75-0.97). CONCLUSIONS: There was good interobserver agreement in the classification of DSC perfusion tissue signal-intensity time curves for pediatric brain tumors, particularly for T1-dominant leakage. Among patients with pediatric brain tumors, a T1-dominant leakage pattern is highly specific for a low-grade tumor and demonstrates high sensitivity and specificity for pilocytic or pilomyxoid astrocytomas.


Assuntos
Astrocitoma/patologia , Neoplasias Encefálicas/patologia , Imageamento por Ressonância Magnética/métodos , Gradação de Tumores/métodos , Adulto , Criança , Meios de Contraste , Feminino , Humanos , Masculino , Estudos Retrospectivos , Sensibilidade e Especificidade
13.
AJNR Am J Neuroradiol ; 36(8): 1572-8, 2015 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-26138138

RESUMO

BACKGROUND AND PURPOSE: Proton radiotherapy has been increasingly utilized to treat pediatric brain tumors, however, limited information exists regarding radiation necrosis among these patients. Our aim was to evaluate the incidence, timing, clinical significance, risk factors, and imaging patterns of radiation necrosis in pediatric patients with brain tumors treated with proton radiation therapy. MATERIALS AND METHODS: A retrospective study was performed on 60 consecutive pediatric patients with primary brain tumors treated with proton radiation therapy. Radiation necrosis was assessed by examining serial MRIs and clinical records to determine the incidence, timing, risk factors, imaging patterns, and clinical significance associated with the development of radiation necrosis in these patients. Radiation necrosis was defined as areas of new enhancement within an anatomic region with previous exposure to proton beam therapy with subsequent decrease on follow-up imaging without changes in chemotherapy. RESULTS: Thirty-one percent of patients developed radiation necrosis with a median time to development of 5.0 months (range, 3-11 months). Risk factors included multiple chemotherapy agents (>3 cytotoxic agents) and atypical teratoid rhabdoid tumor pathology (P = .03 and P = .03, respectively). The most common imaging patterns were small (median, 0.9 cm) and multifocal (63% of patients) areas of parenchymal enhancement remote from the surgical site. The median time to complete resolution on imaging was 5.3 months (range, 3-12 months). Among patients with imaging findings of radiation necrosis, 25% demonstrated severe symptoms with medical intervention indicated. CONCLUSIONS: Pediatric patients with brain tumors treated with proton radiation therapy demonstrate a high incidence of radiation necrosis and a short time to development of necrosis. Multiple small areas of necrosis are frequently identified on imaging. Exposure to multiple chemotherapy agents was a significant risk factor associated with radiation necrosis in these patients.


Assuntos
Neoplasias Encefálicas/radioterapia , Terapia com Prótons/efeitos adversos , Lesões por Radiação/epidemiologia , Lesões por Radiação/etiologia , Antineoplásicos/administração & dosagem , Antineoplásicos/efeitos adversos , Neoplasias Encefálicas/tratamento farmacológico , Neoplasias Encefálicas/patologia , Quimiorradioterapia/efeitos adversos , Criança , Pré-Escolar , Feminino , Humanos , Incidência , Imageamento por Ressonância Magnética , Masculino , Estudos Retrospectivos , Fatores de Risco , Fatores de Tempo
14.
J Laryngol Otol ; 128(11): 1022-3, 2014 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-25274107

RESUMO

BACKGROUND: Synovial sarcoma is a high-grade, soft tissue, malignant disease associated with poor outcome. Typically, synovial sarcoma involves the extremities, with less than 10 per cent of cases occurring in the head and neck region. Synovial sarcoma of the paranasal sinuses is a rare entity. This paper presents a case of an elderly patient with synovial sarcoma of the ethmoidal sinus. CASE REPORT: An 80-year-old woman who had right epistaxis underwent nasal endoscopy and biopsy. The pathology indicated synovial sarcoma and the patient underwent endoscopic excision of the tumour. CONCLUSION: Synovial sarcoma of the ethmoidal sinus is very rare. Patients should undergo excision of the tumour with post-operative radiotherapy. However, the prognosis remains poor and usually the patient succumbs to death within a year.


Assuntos
Seio Etmoidal/patologia , Sarcoma Sinovial/patologia , Idoso de 80 Anos ou mais , Diagnóstico Diferencial , Seio Etmoidal/cirurgia , Feminino , Humanos , Recidiva Local de Neoplasia/patologia , Prognóstico , Sarcoma Sinovial/radioterapia , Sarcoma Sinovial/cirurgia
15.
J Acoust Soc Am ; 136(1): 213-25, 2014 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-24993208

RESUMO

This study used scale model experiments to investigate the insertion losses of balconies on a building façade in the presence of ground reflections. The experiments measured both A-weighted broad- and narrowband insertion loss spectra. The underlying wave interactions/interferences and their couplings with and without reflections from the balcony ceilings were also examined in detail, and these findings were related to the dimensions and elevations of the balconies. The findings indicate that the ground and ceiling reflections and their interferences with the direct sound play very important roles in shaping the frequency characteristics of the insertion losses. Strong sound attenuation can be attained with a carefully designed geometry and acoustical properties of the balcony and the balcony ceiling.

16.
Nano Lett ; 14(6): 3130-7, 2014 Jun 11.
Artigo em Inglês | MEDLINE | ID: mdl-24807793

RESUMO

A well-behaved spin-light emitting diode (LED) composed of InGaN/GaN multiple quantum disks (MQDs), ferromagnetic contact, and Fe3O4 nanoparticles has been designed, fabricated, and characterized. The degree of circular polarization of electroluminescence (EL) can reach up to a high value of 10.9% at room temperature in a low magnetic field of 0.35 T, which overcomes a very low degree of spin polarization in nitride semiconductors due to the weak spin-orbit interaction. Several underlying mechanisms play significant roles simultaneously in this newly designed device for the achievement of such a high performance. Most of all, the vacancy between nanodisks can be filled by half-metal nanoparticles with suitable energy band alignment, which enables selective transfer of spin polarized electrons and holes and leads to the enhanced output spin polarization of LED. Unlike previously reported mechanisms, this new process leads to a weak dependence of spin relaxation on temperature. Additionally, the internal strain in planar InGaN/GaN multiple quantum wells can be relaxed in the nanodisk formation process, which leads to the disappearance of Rashba Hamiltonian and enhances the spin relaxation time. Our approach therefore opens up a new route for the further research and development of semiconductor spintronics.

17.
AJNR Am J Neuroradiol ; 35(4): 815-23, 2014 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-24200900

RESUMO

BACKGROUND AND PURPOSE: Supratentorial tumors in the first year of life are typically large and heterogeneous at presentation, making differentiation of these CNS neoplasms on pre-operative imaging difficult. We hypothesize that the ADC value can reliably differentiate high- versus low-grade supratentorial tumors in this patient population. MATERIALS AND METHODS: A blinded review of ADC maps was performed on 19 patients with histologically proved supratentorial brain tumors diagnosed within the first year of life. Minimum ADC values obtained by region of interest from 2 neuroradiologists were averaged and compared with World Health Organization tumor grade. ADC values for the entire tumor were also obtained by use of a semi-automated histogram method and compared with World Health Organization tumor grade. Data were analyzed by use of Spearman ρ and Student t test, with a value of P < .05 considered statistically significant. RESULTS: For the manual ADC values, a significant negative correlation was found between the mean minimum ADC and tumor grade (P = .0016). A significant difference was found between the mean minimum ADC of the low-grade (1.14 × 10(-3) mm(2)/s ± 0.30) and high-grade tumors (0.64 × 10(-3) mm(2)/s ± 0.28) (P = .0018). Likewise, the semi-automated method demonstrated a significant negative correlation between the lowest 5th (P = .0002) and 10th (P = .0009) percentile individual tumor ADC values and tumor grade, a significant difference between the mean 5th and 10th percentile ADC values of the low-grade and high-grade groups (P = .0028), and a significant positive correlation with values obtained by manual region-of-interest placement (P < .000001). CONCLUSIONS: ADC maps can differentiate high- versus low-grade neoplasms for supratentorial tumors presenting in the first year of life, given the significant negative correlation between ADC values and tumor grade.


Assuntos
Imagem de Difusão por Ressonância Magnética/métodos , Ganglioglioma/patologia , Tumor Rabdoide/patologia , Neoplasias Supratentoriais/patologia , Teratoma/patologia , Artefatos , Córtex Cerebral/patologia , Diagnóstico Diferencial , Feminino , Humanos , Lactente , Recém-Nascido , Masculino , Gradação de Tumores , Estudos Retrospectivos , Sensibilidade e Especificidade , Organização Mundial da Saúde
18.
Artigo em Inglês | MEDLINE | ID: mdl-23573131

RESUMO

Background. Acupuncture and electroacupuncture treatments of damaged nerves may aid nerve regeneration related to hindlimb function, but the effects on the forelimb-related median nerve were not known. Methods. A gap was made in the median nerve of each rat by suturing the stumps into silicone rubber tubes. The influences of acupuncture and electroacupuncture treatments on transected median nerve regeneration were evaluated from morphological, electrophysiological, and functional angles. Results. Morphologically, the group receiving acupuncture and electroacupuncture treatments had larger total nerve area and blood vessel number compared with the controls. Electrophysiologically, the group receiving electroacupuncture had significantly larger amplitude and larger area of the evoked muscle action potentials compared with the controls. Functionally, the acupuncture and electroacupuncture treatments enhanced the injured paw's ability to regain its grasping power and resulted in a faster efficiency to a new bilateral balance. Conclusion. Our findings provide multiapproach evidence of the efficacy of acupuncture and electroacupuncture treatments to the regeneration of median nerve. Indeed, acupuncture and electroacupuncture appear to have positive effects on the regeneration processes. This platform is beneficial to further study the clinical application of acupuncture and electroacupuncture alternative treatments on nerve-injured patients.

19.
Acta Biomater ; 8(7): 2788-94, 2012 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-22475784

RESUMO

The effect of increasing strut porosity on the osteoinductive ability of silicate substituted calcium phosphate (SiCaP) biomaterials was investigated in an ectopic ovine model. Implants with strut porosities of 22.5%, 32.0% and 46.0% were inserted into the parapsinalis muscle. At 8, 12 and 24 weeks histological sections were prepared. Sections were examined using backscattered scanning electron microscopy and un-decalcified histology. Bone area, implant area and bone-implant contact were quantified. At 8 weeks there was no significant difference between the groups in terms of bone area and implant area. However at 12 weeks, the amount of bone formation observed was significantly greater in SiCaP-46 (6.17 ± 1.51%) when compared with SiCaP-22.5 (1.33 ± 0.84%) p=0.035. Results also showed significantly increased amounts of bone-implant contact to the SiCaP-46 scaffold (3.30 ± 1.17%) compared with SiCaP-22.5 (0.67 ± 0.52%, p=0.043) at 8 weeks and 12 weeks; (SiCaP-46 (21.82 ± 5.59%) vs SiCaP-22.5 (3.06 ± 1.89%), p=0.012). At 24 weeks, bone formation and graft resorption had significantly increased in all groups so that the level of bone formation in the SiCaP-46 group had increased 75-fold to 30.05 ± 8.38%. Bone formation was observed in pores <10 µm. Results suggest that bone graft substitute materials with greater strut porosity are more osteoinductive.


Assuntos
Materiais Biocompatíveis/farmacologia , Substitutos Ósseos/farmacologia , Transplante Ósseo , Fosfatos de Cálcio/farmacologia , Osseointegração/efeitos dos fármacos , Animais , Feminino , Implantes Experimentais , Microscopia Eletrônica de Varredura , Osteogênese/efeitos dos fármacos , Porosidade/efeitos dos fármacos , Implantação de Prótese , Ovinos , Alicerces Teciduais/química
20.
Neuroradiol J ; 25(6): 671-5, 2012 Dec 20.
Artigo em Inglês | MEDLINE | ID: mdl-24029179

RESUMO

Posterior reversible encephalopathy syndrome (PRES) is a clinicoradiologic condition that typically demonstrates symmetric occipitoparietal vasogenic edema on CT and MR imaging. The vasogenic edema typically resolves over a period of days to weeks if the underlying hemodynamic abnormality is promptly corrected. Less commonly, PRES may be complicated by hemorrhage or cytotoxic edema that restricts diffusion and usually involves the cerebral cortex. Cortical laminar necrosis (CLN) is a sequela of cerebral energy depletion, resulting in selective necrosis of the most metabolically active cortical layers. Cortical hemorrhage is an atypical feature of CLN. We present a unique PRES case with imaging features of both CLN and CT negative hemorrhage. CLN with CT negative hemorrhage in the setting of PRES has not been previously reported to the best of our knowledge.

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