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1.
Artigo em Inglês | MEDLINE | ID: mdl-31939649

RESUMO

Although they have attracted enormous attention in recent years, software-based and two-dimensional hardware-based artificial neural networks (ANNs) may consume a great deal of power. Because there will be numerous data transmissions through a long interconnection for learning, power consumption in the interconnect will be an inevitable problem for low-power computing. Therefore, we suggest and report 3D stackable synaptic transistors for 3D ANNs, which would be the strongest candidate in future computing systems by minimizing power consumption in the interconnection. To overcome the problems of enormous power consumption, it might be necessary to introduce a 3D stackable ANN platform. With this structure, short vertical interconnection can be realized between the top and bottom devices, and the integration density can be significantly increased for integrating numerous neuromorphic devices. In this paper, we suggest and show the feasibility of monolithic 3D integration of synaptic devices using the channel layer transfer method through a wafer bonding technique. Using a low-temperature processible III-V and composite oxide (Al2O3/HfO2/Al2O3)-based weight storage layer, we successfully demonstrated synaptic transistors showing good linearity (αp/αd = 1.8/0.5), a high transconductance ratio (6300), and very good stability. High learning accuracy of 97% was obtained in the training of 1 million MNIST images based on the device characteristics.

2.
J Cardiovasc Imaging ; 28(1): 21-32, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31805621

RESUMO

BACKGROUND: To assess left ventricular function and coronary artery simultaneously by third-generation dual-source computed tomography (CT) using a low radiation dose. METHODS: A total of 48 patients (36 men, 12 women; mean age 57.0 ± 9.5 years) who underwent both electrocardiography-gated cardiac CT angiography (CCTA) using 70-90 kVp and echocardiography were included in this retrospective study. The correlation between left ventricular end-diastolic volume (LVEDV), left ventricular end-systolic volume (LVESV), and left ventricular ejection fraction (LVEF) measured using CCTA and echocardiography was determined. The quality of coronary artery images was analyzed using a 4-point scale (1, excellent; 4, poor). The effective radiation dose of CCTA was calculated. RESULTS: Mean heart rate during the CT examination was 59.9 ± 9.9 bpm (range 38-79) and the body mass index of 48 patients was 24.5 ± 2.6 kg/m² (range 17.0-29.4). LVEDV, LVESV, and LVEF measured using CCTA and echocardiography demonstrated a fair to moderate correlation (Pearson correlation coefficient: r = 0.395, p = 0.005 for LVEDV; r = 0.509. p < 0.001 for LVESV; r = 0.551, p < 0.001 for LVEF). Average image quality score of coronary arteries was 1.0 ± 0.1 (range 1-2). A total of 99.0% (783 of 791) of segments had an excellent image quality score, and 1.0% (8 of 791) of segments had a good score. Mean effective radiation dose was 2.2 ± 0.7 mSv. CONCLUSIONS: Third-generation dual-source CT using a low tube voltage simultaneously provides information regarding LV function and coronary artery disease at a low radiation dose. It can serve as an alternative option for functional assessment, particularly when other imaging modalities are inadequate.

3.
PLoS One ; 14(11): e0224430, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31743333

RESUMO

The prognostic significance of tumor-infiltrating lymphocytes has been determined in cancers of the lung, colon and breast, though there is no standardized method for using this prognostic indicator for lung cancer. We applied a modified version of the method proposed by the International Immuno-Oncology Biomarkers Working Group to primary lung adenocarcinoma, which uses histologic findings of hematoxylin and eosin sections. The study included a total cohort of 146 lung adenocarcinoma patients who underwent lobectomy with lymph node dissection at two hospitals between 2008 and 2012. The full-face sections of hematoxylin and eosin-stained slides were reviewed, and we evaluated the level of tumor-infiltrating lymphocytes as a percentage of the area occupied out of the total intra-tumoral stromal area. Histopathologic factors include histologic grade, necrosis, extracellular mucin, lymphovascular invasion, lymph node metastasis, level of tumor infiltrating lymphocytes, tertiary lymphoid structures around the tumor, and the presence of a germinal center in tertiary lymphoid structures. The high level of tumor-infiltrating lymphocytes was found to be significantly correlated with the histologic grade (p = 0.023), necrosis (p = 0.042), abundance of tertiary lymphoid structures(p<0.001) and presence of a germinal center in tertiary lymphoid structures (p = 0.004). A high level of tumor-infiltrating lymphocytes was associated with better progression-free survival (p = 0.011) as well as overall survival (p = 0.049). On multivariable analysis, high tumor-infiltrating lymphocyte levels were a good independent prognostic factor for progression-free survival (Hazard ratio: 0.389, 95% confidence interval: 0.161-0.941, p = 0.036). Histologic evaluation of tumor-infiltrating lymphocytes level in lung adenocarcinoma with H&E sections therefore has prognostic value in routine surgical pathology.

4.
Respir Res ; 20(1): 177, 2019 Aug 06.
Artigo em Inglês | MEDLINE | ID: mdl-31387600

RESUMO

BACKGROUND: Generally, structural destruction of lung parenchyma, such as pulmonary emphysema, is considered to be related to the low diagnostic yields and high complication rates of lung biopsies of peripheral lung lesions. Currently, little is known about the clinical outcomes of using endobronchial ultrasound with a guide sheath (EBUS-GS) to diagnose peripheral lesions in patients with emphysema. METHODS: This retrospective study was performed to identify the clinical outcomes of EBUS-GS in patients with pulmonary emphysema. This study included 393 consecutive patients who received EBUS-GS between February 2017 and April 2018. The patients were classified according to the severity of their emphysema, and factors possibly contributing to a successful EBUS-GS procedure were evaluated. RESULTS: The overall diagnostic yield of EBUS-GS in patients with no or mild emphysema was significantly higher than in those with moderate or severe pulmonary emphysema (78% vs. 61%, P = 0.007). There were no procedure-related complications. The presence of a bronchus sign on CT (P <  0.001) and a "within the lesion" status on EBUS (P = 0.009) were independently associated with a successful EBUS-GS procedure. Although the diagnostic yield of EBUS-GS in patients with moderate-to-severe emphysema was relatively low, a bronchus sign and "within the lesion" status on EBUS were contributing factors for a successful EBUS-GS. CONCLUSIONS: EBUS-GS is a safe procedure with an acceptable diagnostic yield, even when performed in patients with pulmonary emphysema. The presence of a bronchus sign and "within the lesion" status on EBUS were predictors of a successful procedure.


Assuntos
Endossonografia/instrumentação , Endossonografia/métodos , Pulmão/diagnóstico por imagem , Enfisema Pulmonar/diagnóstico por imagem , Idoso , Feminino , Humanos , Pulmão/fisiopatologia , Masculino , Pessoa de Meia-Idade , Enfisema Pulmonar/fisiopatologia , Estudos Retrospectivos , Tomografia Computadorizada por Raios X/métodos , Resultado do Tratamento
5.
AJR Am J Roentgenol ; 212(4): 748-754, 2019 04.
Artigo em Inglês | MEDLINE | ID: mdl-30900916

RESUMO

OBJECTIVE: Although CT has been used as a complementary diagnostic method for the preoperative diagnosis of thyroid cancer, it has the shortcomings of substantial radiation exposure and the use of contrast material (CM). The purpose of this article is to evaluate the image quality and diagnostic performance of 70-kVp thyroid CT with low volumes of CM versus conventional 120-kVp thyroid CT protocol. MATERIALS AND METHODS: Eighty patients referred for preoperative thyroid CT were randomly divided into two groups (group A: 40 patients, 70 kVp, 60 mL of CM; group B: 40 patients, 120 kVp, 100 mL of CM). Quantitative and qualitative image quality and radiation doses for the two groups were compared using the Mann-Whitney U and chi-square tests. Degrees of agreement between preoperative CT staging and pathologic results were evaluated and compared using the Wald statistic. RESULTS: Calculated signal-to-noise ratios of different anatomic structures, calculated contrast-to-noise ratios, overall image quality, subjective noise, and streak artifacts were not significantly different between the two groups (all p > 0.05), and neither were the accuracies of preoperative CT staging (all p > 0.05). The estimated effective doses were significantly lower in group A (mean [± SD], 0.52 ± 0.14 mSv in group A and 2.28 ± 0.29 mSv in group B; p < 0.001). CONCLUSION: Ultra-low-dose 70-kVp CT with a low volume of CM provides sufficient image quality for preoperative staging of thyroid cancer and substantially reduces the radiation dose compared with standard 120-kVp CT.


Assuntos
Neoplasias da Glândula Tireoide/diagnóstico por imagem , Tomografia Computadorizada por Raios X/métodos , Adulto , Idoso , Meios de Contraste , Feminino , Humanos , Iohexol/análogos & derivados , Masculino , Pessoa de Meia-Idade , Estadiamento de Neoplasias , Doses de Radiação , Interpretação de Imagem Radiográfica Assistida por Computador , Estudos Retrospectivos , Razão Sinal-Ruído , Neoplasias da Glândula Tireoide/patologia , Neoplasias da Glândula Tireoide/cirurgia , Tireoidectomia
6.
Korean J Radiol ; 20(1): 94-101, 2019 01.
Artigo em Inglês | MEDLINE | ID: mdl-30627025

RESUMO

Objective: To investigate the efficacy of motion-correction algorithm (MCA) in improving coronary artery image quality and measurement accuracy using an anthropomorphic dynamic heart phantom and 256-detector row computed tomography (CT) scanner. Materials and Methods: An anthropomorphic dynamic heart phantom was scanned under a static condition and under heart rate (HR) simulation of 50-120 beats per minute (bpm), and the obtained images were reconstructed using conventional algorithm (CA) and MCA. We compared the subjective image quality of coronary arteries using a four-point scale (1, excellent; 2, good; 3, fair; 4, poor) and measurement accuracy using measurement errors of the minimal luminal diameter (MLD) and minimal luminal area (MLA). Results: Compared with CA, MCA significantly improved the subjective image quality at HRs of 110 bpm (1.3 ± 0.3 vs. 1.9 ± 0.8, p = 0.003) and 120 bpm (1.7 ± 0.7 vs. 2.3 ± 0.6, p = 0.006). The measurement error of MLD significantly decreased on using MCA at 110 bpm (11.7 ± 5.9% vs. 18.4 ± 9.4%, p = 0.013) and 120 bpm (10.0 ± 7.3% vs. 25.0 ± 16.5%, p = 0.013). The measurement error of the MLA was also reduced using MCA at 110 bpm (19.2 ± 28.1% vs. 26.4 ± 21.6%, p = 0.028) and 120 bpm (17.9 ± 17.7% vs. 34.8 ± 19.6%, p = 0.018). Conclusion: Motion-correction algorithm can improve the coronary artery image quality and measurement accuracy at a high HR using an anthropomorphic dynamic heart phantom and 256-detector row CT scanner.


Assuntos
Angiografia Coronária/métodos , Vasos Coronários/diagnóstico por imagem , Frequência Cardíaca/fisiologia , Coração/diagnóstico por imagem , Tomografia Computadorizada por Raios X/métodos , Algoritmos , Artefatos , Precisão da Medição Dimensional , Humanos , Movimento (Física) , Movimento/fisiologia , Imagens de Fantasmas
7.
Jpn J Radiol ; 37(3): 209-219, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30637569

RESUMO

Many surgical procedures are used for the treatment of lung, heart, and mediastinal diseases. The techniques can result in postoperative complications. The nature of these complications differs according to the duration of thoracic surgery and the onset of the complication. The complications occurring within 1 month and more than 1 month generally considered as early and late complications, respectively. Chest radiographs and CT scans obtained in patients who have undergone thoracic surgery show normal changes during the surgical procedure and diverse postsurgical complications. Familiarity with the clinical and radiologic findings of the normal alterations and possible complications after thoracic surgery is crucial in minimizing the increased morbidity and mortality.


Assuntos
Cardiopatias/cirurgia , Pneumopatias/cirurgia , Imagem por Ressonância Magnética/métodos , Doenças do Mediastino/cirurgia , Complicações Pós-Operatórias/diagnóstico por imagem , Tomografia Computadorizada por Raios X/métodos , Procedimentos Cirúrgicos Cardíacos , Feminino , Coração/diagnóstico por imagem , Humanos , Pulmão/diagnóstico por imagem , Pulmão/cirurgia , Masculino , Mediastino/diagnóstico por imagem , Mediastino/cirurgia , Cirurgia Torácica/métodos
8.
Clin Imaging ; 53: 49-57, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30312855

RESUMO

PURPOSE: We presented details and incidence of systemic arterial embolism (SAE) following a CT-guided percutaneous transthoracic needle biopsy (PTNB) and evaluated risk factors for SAEs. METHODS: We retrospectively evaluated 1014 PTNBs performed in our hospital from 2005 to 2017. SAE was identified in the pulmonary vein, left heart, coronary artery, and aorta by reviewing post-biopsy CT images. Limited post-biopsy CT scans only covering the region biopsied were available until the first case of SAE was identified (n = 503). Then, the entire thorax was scanned for further examination of SAE (n = 511). Eighteen-gauge automatic cutting needles were used in all procedures. When SAE was evident on post-biopsy CT, subsequent brain CT was performed in order to confirm the cerebral SAE. RESULTS: Nine patients (0.89%) developed SAEs. In the univariate analyses, the location of the needle tip relative to the lesion (outside or inside of the lesion) as well as accompanying pulmonary hemorrhage were significant risk factors for SAEs (P = 0.021 and 0.036, respectively). Two patients developed neurological symptoms with cerebral SAEs, and one of these had sequelae. In seven asymptomatic SAEs with no cerebral SAE, four patients were retrospectively-diagnosed cases and three patients were detected on post-biopsy CT images. All seven of these patients had no sequelae. CONCLUSION: The incidence of SAE was higher than expected, due to radiologically detected asymptomatic SAEs. The location of the needle tip relative to the lesion and accompanying pulmonary hemorrhage were significant risk factors for the occurrence of SAEs. We proposed a guideline for treating asymptomatic SAEs.


Assuntos
Biópsia por Agulha/efeitos adversos , Embolia Aérea/etiologia , Agulhas/efeitos adversos , Tórax , Idoso , Aorta , Encéfalo/patologia , Vasos Coronários , Embolia Aérea/terapia , Feminino , Coração , Hemorragia/etiologia , Humanos , Biópsia Guiada por Imagem/métodos , Incidência , Pulmão/patologia , Pneumopatias/etiologia , Masculino , Pessoa de Meia-Idade , Miocárdio , Veias Pulmonares , Radiografia Intervencionista/métodos , Radiologia , Estudos Retrospectivos , Fatores de Risco , Tomografia Computadorizada por Raios X/métodos
9.
BMC Pulm Med ; 18(1): 137, 2018 Aug 13.
Artigo em Inglês | MEDLINE | ID: mdl-30103727

RESUMO

BACKGROUND: The diagnostic yields and safety profiles of transbronchial lung biopsy have not been evaluated in inexperienced physicians using the combined modality of radial probe endobronchial ultrasound and a guide sheath (EBUS-GS). This study assessed the utility and safety of EBUS-GS during the learning phase by referring to a database of performed EBUS-GS procedures. METHODS: From December 2015 to January 2017, all of the consecutive patients who underwent EBUS-GS were registered. During the study period, two physicians with no previous experience performed the procedure. To assess the diagnostic yields, learning curve, and safety profile of EBUS-GS performed by these inexperienced physicians, the first 100 consecutive EBUS-GS procedures were included in the evaluation. RESULTS: The overall diagnostic yield of EBUS-GS performed by two physicans in 200 patients with a peripheral lung lesion was 73.0%. Learning curve analyses showed that the diagnostic yields were stable, even when the procedure was performed by beginners. Complications related to EBUS-GS occurred in three patients (1.5%): pneumothorax developed in two patients (1%) and resolved spontaneously without chest tube drainage; another patient (0.5%) developed a pulmonary infection after EBUS-GS. There were no cases of pneumothorax requiring chest tube drainage, severe hemorrhage, respiratory failure, premature termination of the procedure, or procedure-related mortality. CONCLUSIONS: EBUS-GS is a safe and stable procedure with an acceptable diagnostic yield, even when performed by physicians with no previous experience.


Assuntos
Broncoscopia/métodos , Biópsia Guiada por Imagem/instrumentação , Neoplasias Pulmonares/patologia , Pulmão/patologia , Ultrassonografia de Intervenção/métodos , Idoso , Brônquios/diagnóstico por imagem , Brônquios/patologia , Broncoscopia/efeitos adversos , Competência Clínica , Feminino , Humanos , Biópsia Guiada por Imagem/métodos , Curva de Aprendizado , Pulmão/diagnóstico por imagem , Neoplasias Pulmonares/diagnóstico por imagem , Masculino , Pessoa de Meia-Idade , Pneumotórax/etiologia , República da Coreia , Infecções Respiratórias/etiologia , Estudos Retrospectivos , Tomografia Computadorizada por Raios X , Ultrassonografia de Intervenção/instrumentação
10.
Nano Lett ; 18(7): 4447-4453, 2018 07 11.
Artigo em Inglês | MEDLINE | ID: mdl-29879355

RESUMO

Memristor-based neuromorphic networks have been actively studied as a promising candidate to overcome the von-Neumann bottleneck in future computing applications. Several recent studies have demonstrated memristor network's capability to perform supervised as well as unsupervised learning, where features inherent in the input are identified and analyzed by comparing with features stored in the memristor network. However, even though in some cases the stored feature vectors can be normalized so that the winning neurons can be directly found by the (input) vector-(stored) vector dot-products, in many other cases, normalization of the feature vectors is not trivial or practically feasible, and calculation of the actual Euclidean distance between the input vector and the stored vector is required. Here we report experimental implementation of memristor crossbar hardware systems that can allow direct comparison of the Euclidean distances without normalizing the weights. The experimental system enables unsupervised K-means clustering algorithm through online learning, and produces high classification accuracy (93.3%) for the standard IRIS data set. The approaches and devices can be used in other unsupervised learning systems, and significantly broaden the range of problems a memristor-based network can solve.

11.
Acta Radiol ; 59(2): 170-179, 2018 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-28475022

RESUMO

Background Using the hybrid electrocardiogram (ECG)-gated computed tomography (CT) technique, assessment of entire aorta, coronary arteries, and aortic valve can be possible using single-bolus contrast administration within a single acquisition. Purpose To compare the image quality of hybrid ECG-gated and non-gated CT angiography of the aorta and evaluate the effect of a motion correction algorithm (MCA) on coronary artery image quality in a hybrid ECG-gated aorta CT group. Material and Methods In total, 104 patients (76 men; mean age = 65.8 years) prospectively randomized into two groups (Group 1 = hybrid ECG-gated CT; Group 2 = non-gated CT) underwent wide-detector array aorta CT. Image quality, assessed using a four-point scale, was compared between the groups. Coronary artery image quality was compared between the conventional reconstruction and motion correction reconstruction subgroups in Group 1. Results Group 1 showed significant advantages over Group 2 in aortic wall, cardiac chamber, aortic valve, coronary ostia, and main coronary arteries image quality (all P < 0.001). All Group 1 patients had diagnostic image quality of the aortic wall and left ostium. The MCA significantly improved the image quality of the three main coronary arteries ( P < 0.05). Moreover, per-vessel interpretability improved from 92.3% to 97.1% with the MCA ( P = 0.013). Conclusion Hybrid ECG-gated CT significantly improved the heart and aortic wall image quality and the MCA can further improve the image quality and interpretability of coronary arteries.


Assuntos
Aortografia/métodos , Angiografia por Tomografia Computadorizada/métodos , Angiografia Coronária/métodos , Eletrocardiografia/métodos , Idoso , Algoritmos , Aorta , Feminino , Humanos , Aumento da Imagem , Masculino , Estudos Prospectivos , Doses de Radiação , Distribuição Aleatória
12.
Acta Radiol ; 59(5): 553-559, 2018 May.
Artigo em Inglês | MEDLINE | ID: mdl-28786301

RESUMO

Background Reducing radiation dose inevitably increases image noise, and thus, it is important in low-dose computed tomography (CT) to maintain image quality and lesion detection performance. Purpose To assess image quality and lesion conspicuity of ultra-low-dose CT with model-based iterative reconstruction (MBIR) and to determine a suitable protocol for lung screening CT. Material and Methods A total of 120 heavy smokers underwent lung screening CT and were randomly and equally assigned to one of five groups: group 1 = 120 kVp, 25 mAs, with FBP reconstruction; group 2 = 120 kVp, 10 mAs, with MBIR; group 3 = 100 kVp, 15 mAs, with MBIR; group 4 = 100 kVp, 10 mAs, with MBIR; and group 5 = 100 kVp, 5 mAs, with MBIR. Two radiologists evaluated intergroup differences with respect to radiation dose, image noise, image quality, and lesion conspicuity using the Kruskal-Wallis test and the Chi-square test. Results Effective doses were 61-87% lower in groups 2-5 than in group 1. Image noises in groups 1 and 5 were significantly higher than in the other groups ( P < 0.001). Overall image quality was best in group 1, but diagnostic acceptability of overall image qualities in groups 1-3 was not significantly different (all P values > 0.05). Lesion conspicuities were similar in groups 1-4, but were significantly poorer in group 5. Conclusion Lung screening CT with MBIR obtained at 100 kVp and 15 mAs enables a ∼60% reduction in radiation dose versus low-dose CT, while maintaining image quality and lesion conspicuity.


Assuntos
Pneumopatias/diagnóstico por imagem , Interpretação de Imagem Radiográfica Assistida por Computador/métodos , Tomografia Computadorizada por Raios X/métodos , Idoso , Artefatos , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Doses de Radiação
13.
Korean J Radiol ; 18(4): 643-654, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28670159

RESUMO

OBJECTIVE: To evaluate the utility of cardiovascular magnetic resonance (CMR)-derived myocardial strain measurement for the prediction of poor outcomes in patients with acute myocarditis. MATERIALS AND METHODS: We retrospectively analyzed data from 37 patients with acute myocarditis who underwent CMR. Left ventricular (LV) size, LV mass index, ejection fraction and presence of myocardial late gadolinium enhancement (LGE) were analyzed. LV circumferential strain (EccSAX), radial strain (ErrSAX) from mid-ventricular level short-axis cine views and LV longitudinal strain (EllLV), radial strain (ErrLax) measurements from 2-chamber long-axis views were obtained. In total, 31 of 37 patients (83.8%) underwent follow-up echocardiography. The primary outcome was major adverse cardiovascular event (MACE). Incomplete LV functional recovery was a secondary outcome. RESULTS: During an average follow-up of 41 months, 11 of 37 patients (29.7%) experienced MACE. Multivariable Cox proportional hazard regression analysis, which included LV mass index, LV ejection fraction, the presence of LGE, EccSAX, ErrSAX, EllLV, and ErrLax values, indicated that the presence of LGE (hazard ratio, 42.88; p = 0.014), together with ErrLax (hazard ratio, 0.77 per 1%, p = 0.004), was a significant predictor of MACE. Kaplan-Meier analysis demonstrated worse outcomes in patient with LGE and an ErrLax value ≤ 9.48%. Multivariable backward regression analysis revealed that ErrLax values were the only significant predictors of LV functional recovery (hazard ratio, 0.54 per 1%; p = 0.042). CONCLUSION: CMR-derived ErrLax values can predict poor outcomes, both MACE and incomplete LV functional recovery, in patients with acute myocarditis, while LGE is only a predictor of MACE.


Assuntos
Imagem Cinética por Ressonância Magnética , Miocardite/diagnóstico por imagem , Doença Aguda , Adulto , Idoso , Área Sob a Curva , Progressão da Doença , Ecocardiografia , Feminino , Gadolínio/química , Ventrículos do Coração/diagnóstico por imagem , Humanos , Estimativa de Kaplan-Meier , Masculino , Pessoa de Meia-Idade , Miocardite/mortalidade , Miocardite/patologia , Valor Preditivo dos Testes , Prognóstico , Modelos de Riscos Proporcionais , Curva ROC , Estudos Retrospectivos , Função Ventricular Esquerda
14.
Acta Radiol ; 58(5): 550-557, 2017 May.
Artigo em Inglês | MEDLINE | ID: mdl-27565631

RESUMO

Background Although fibrotic idiopathic interstitial pneumonias (IIPs) alone and those combined with pulmonary emphysema are naturally progressive diseases, the process of deterioration and outcomes are variable. Purpose To evaluate and compare serial changes of computed tomography (CT) abnormalities and prognostic predictive factors in fibrotic IIPs alone and those combined with pulmonary emphysema. Material and Methods A total of 148 patients with fibrotic IIPs alone (82 patients) and those combined with pulmonary emphysema (66 patients) were enrolled. Semi-quantitative CT analysis was used to assess the extents of CT characteristics which were evaluated on initial and follow-up CT images. Univariate and multivariate analyses were performed to assess the effects of clinical and CT variables on survival. Results Significant differences were noted between fibrotic scores, as determined using initial CT scans, in the fibrotic IIPs alone (21.22 ± 9.83) and those combined with pulmonary emphysema groups (14.70 ± 7.28) ( P < 0.001). At follow-up CT scans, changes in the extent of ground glass opacities (GGO) were greater ( P = 0.031) and lung cancer was more prevalent ( P = 0.001) in the fibrotic IIPs combined with pulmonary emphysema group. Multivariate Cox proportional hazards analysis showed changes in the extent of GGO (hazard ratio, 1.056) and the presence of lung cancer (hazard ratio, 4.631) were predictive factors of poor survivals. Conclusion Although patients with fibrotic IIPs alone and those combined with pulmonary emphysema have similar mortalities, lung cancer was more prevalent in patients with fibrotic IIPs combined with pulmonary emphysema. Furthermore, changes in the extent of GGO and the presence of lung cancer were independent prognostic factors of poor survivals.


Assuntos
Pneumonias Intersticiais Idiopáticas/diagnóstico por imagem , Fibrose Pulmonar Idiopática/diagnóstico por imagem , Enfisema Pulmonar/diagnóstico por imagem , Tomografia Computadorizada por Raios X/métodos , Idoso , Feminino , Humanos , Pneumonias Intersticiais Idiopáticas/fisiopatologia , Fibrose Pulmonar Idiopática/complicações , Fibrose Pulmonar Idiopática/fisiopatologia , Pulmão/diagnóstico por imagem , Pulmão/fisiopatologia , Masculino , Prognóstico , Enfisema Pulmonar/complicações , Enfisema Pulmonar/fisiopatologia , Estudos Retrospectivos
15.
Nanoscale ; 9(1): 45-51, 2017 Jan 07.
Artigo em Inglês | MEDLINE | ID: mdl-27906389

RESUMO

Recent studies have shown that nanoionic-based memristors can offer rich internal dynamics during ion movement that enables these solid-state devices to emulate various synaptic functions in biological systems naturally. The experimental observations can be explained within the 2nd-order memristor theoretical framework, which states that the device conductance (weight) can be determined by multiple internal state variables that can be modulated at different time scales and lead to different activity-dependent synaptic behaviors. Here, we show experimentally that not only the synaptic weight, but also synaptic plasticity (i.e. polarity and the rate of weight change) depends on the history of the input activities. This "plasticity of plasticity" resembles metaplasticity effects observed in biological systems, which have been found to facilitate neuron competition and stability. Specifically, we show that the memristor device may exhibit the same apparent weight (conductance) after experiencing different history of activities, but when subjected to additional, identical stimulation conditions, the device will however exhibit very different responses including the polarity and rate of weight (conductance) change. These findings serve to further our knowledge of fundamental physical mechanisms in memristors, and help advance adaptive artificial neuromorphic systems based on these emerging devices.

16.
J Comput Assist Tomogr ; 40(5): 777-83, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27454785

RESUMO

OBJECTIVE: The aim of the study was to assess the effectiveness of the adaptive statistical iterative reconstruction (ASIR) for dual-energy computed tomography pulmonary angiography (DE-CTPA) with a reduced iodine load. MATERIALS AND METHODS: One hundred forty patients referred for chest CT were randomly divided into a DE-CTPA group with a reduced iodine load or a standard CTPA group. Quantitative and qualitative image qualities of virtual monochromatic spectral (VMS) images with filtered back projection (VMS-FBP) and those with 50% ASIR (VMS-ASIR) in the DE-CTPA group were compared. Image qualities of VMS-ASIR images in the DE-CTPA group and ASIR images in the standard CTPA group were also compared. RESULTS: All quantitative and qualitative indices, except attenuation value of pulmonary artery in the VMS-ASIR subgroup, were superior to those in the VMS-FBP subgroup (all P < 0.001). Noise and signal-to-noise ratio of VMS-ASIR images were superior to those of ASIR images in the standard CTPA group (P < 0.001 and P = 0.007, respectively). Regarding qualitative indices, noise was significantly lower in VMS-ASIR images of the DE-CTPA group than in ASIR images of the standard CTPA group (P = 0.001). CONCLUSIONS: The ASIR technique tends to improve the image quality of VMS imaging. Dual-energy computed tomography pulmonary angiography with ASIR can reduce contrast medium volume and produce images of comparable quality with those of standard CTPA.


Assuntos
Angiografia por Tomografia Computadorizada/métodos , Iodo/administração & dosagem , Embolia Pulmonar/diagnóstico por imagem , Intensificação de Imagem Radiográfica/métodos , Interpretação de Imagem Radiográfica Assistida por Computador/métodos , Imagem Radiográfica a Partir de Emissão de Duplo Fóton/métodos , Adulto , Idoso , Algoritmos , Meios de Contraste/administração & dosagem , Interpretação Estatística de Dados , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Reprodutibilidade dos Testes , Sensibilidade e Especificidade
17.
J Thorac Imaging ; 31(2): 104-10, 2016 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-26891073

RESUMO

PURPOSE: The aim of the study was to correlate computed tomographic (CT) scoring systems for pulmonary sarcoidosis with cardiopulmonary exercise testing and evaluate which scoring system provides the most reliable information for assessing disease severity and predicting impairment of gas exchange during exercise. MATERIALS AND METHODS: The institutional review board approved this retrospective study. All 62 patients underwent thin-section CT, pulmonary function tests, and cardiopulmonary exercise test. Two observers scored CT images according to scoring systems published by Remy-Jardin and colleagues. Spearman rank correlation coefficients were calculated between CT patterns and pulmonary functional impairment parameters, and multiple regression analyses were performed to evaluate which CT abnormalities were significantly associated with pulmonary functional impairment parameters. RESULTS: Regardless of scoring system, PaO2max was significantly associated with the subscores of ground-glass opacity, linear opacity, and total CT scores. Multiple regression analyses showed that subscores of ground-glass and linear opacity in the Leung scoring system appeared to explain a significant amount of variance in functional parameters at rest and at maximal exercise. CONCLUSIONS: CT findings, particularly ground-glass opacity and linear abnormalities, can explain a significant amount of variance in cardiopulmonary exercise parameters. This suggests that CT-based scoring systems are valid measures of disease severity in sarcoidosis.


Assuntos
Teste de Esforço , Sarcoidose Pulmonar/diagnóstico por imagem , Tomografia Computadorizada por Raios X , Adulto , Idoso , Feminino , Humanos , Pulmão/diagnóstico por imagem , Masculino , Pessoa de Meia-Idade , Reprodutibilidade dos Testes , Testes de Função Respiratória/estatística & dados numéricos , Estudos Retrospectivos , Índice de Gravidade de Doença
18.
Clin Nucl Med ; 41(1): 8-14, 2016 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-26284773

RESUMO

PURPOSE: The aim of this study was to investigate the value of morphologic, functional, and metabolic biomarkers acquired concurrently at PET/MRI in patients with thymic epithelial tumors. PATIENTS AND METHODS: During 1 year, 9 patients with suspected thymic epithelial tumors at contrast-enhanced chest CT were prospectively enrolled and underwent preoperative 18F-FDG PET/MRI. Two chest radiologists prospectively reviewed the CT and MRI scans of PET/MRI in consensus, and 2 nuclear physicians reviewed the PET images. Visual assessment of the tumor morphology, functional biomarkers such as apparent diffusion coefficient from diffusion-weighted images, and metabolic biomarkers (including SUVmax, metabolic tumor volume, total lesion glycolysis, and heterogeneity index) were recorded. All patients underwent operation, and their pathologic reports served as the reference standard. RESULTS: Thymic epithelial tumors were demonstrated in all 9 patients at pathologic examination. Tumor contour (P = 0.012) and shape (P = 0.033) had an association with the World Health Organization subtype, and the presence of septum (P = 0.048) on MRI scans had an association with the Masaoka stage. In terms of functional and metabolic biomarkers, SUVmax (ρ = 0.683, P = 0.042) and SUV/apparent diffusion coefficient (ρ = 0.703, P = 0.035) correlated with the Masaoka stage. Metabolic tumor volume (P = 0.024), heterogeneity index (P = 0.024), and total lesion glycolysis (P = 0.048) were useful for classification between low- and high-risk thymic epithelial tumors. CONCLUSIONS: Although limited by the small number of patients enrolled, morphologic, functional, and metabolic biomarkers derived from PET/MRI scans were useful for the stratification of thymic epithelial tumors.


Assuntos
Biomarcadores Tumorais/metabolismo , Fluordesoxiglucose F18 , Imagem por Ressonância Magnética , Imagem Multimodal , Neoplasias Epiteliais e Glandulares/diagnóstico por imagem , Neoplasias Epiteliais e Glandulares/metabolismo , Tomografia por Emissão de Pósitrons , Neoplasias do Timo/diagnóstico por imagem , Neoplasias do Timo/metabolismo , Adulto , Idoso , Biomarcadores , Imagem de Difusão por Ressonância Magnética , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Neoplasias Epiteliais e Glandulares/patologia , Neoplasias Epiteliais e Glandulares/fisiopatologia , Tomografia por Emissão de Pósitrons/métodos , Compostos Radiofarmacêuticos , Neoplasias do Timo/patologia , Neoplasias do Timo/fisiopatologia , Tomografia Computadorizada por Raios X , Carga Tumoral
19.
Lasers Surg Med ; 47(9): 745-55, 2015 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-26391894

RESUMO

BACKGROUND AND OBJECTIVE: Bone homeostasis is maintained by a balance between osteoblastic bone formation and osteoclastic bone resorption, where intracellular reactive oxygen species (ROS) are crucial mediators of osteoclastogenesis. Recently, low-level light therapy (LLLT), a form of laser medicine used in various clinical fields, was shown to alleviate oxidative stress by scavenging intracellular ROS. The present study aimed to investigate the impact of 635 nm irradiation from a light-emitting diode (LED) on osteoclastogenesis from receptor activator of nuclear factor kappa-B (NF-κB) ligand (RANKL)-stimulated mouse bone marrow-derived macrophages (BMMs). STUDY DESIGN/MATERIALS AND METHODS: The effects of LED irradiation on osteoclastogenesis were assessed in tartrate-resistant acid phosphatase (TRAP), 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), cell viability, and resorption pit formation, respectively. Quantitative real-time polymerase chain reaction (qPCR) and Western blot analyses were also performed to assess mRNA expression of osteoclastogenesis-related genes and phosphorylation of extracellular signal-regulated kinase 1/2 (ERK 1/2), p38, and c-Jun-N-terminal kinase (JNK). NF-κB activity was assayed by luciferase reporter assay and Intracellular ROS generation was investigated by the 2',7'-dichlorodihydrofluorescein diacetate (H2 DCF-DA) detection method. RESULTS: LED irradiation significantly inhibited RANKL-mediated osteoclast differentiation from BMMs and mRNA expression of TRAP, osteoclast-associated immunoglobulin-like receptor (OSCAR), and dendrocyte-expressed seven-transmembrane protein (DC-STAMP). Exposure to LED light likewise significantly decreased RANKL-facilitated NF-κB activity, p38 and ERK phosphorylation and intracellular ROS generation, and increased gene expression of nuclear factor E2-related factor 2 (Nrf2). CONCLUSIONS: Taken together, the results presented herein show that LED irradiation downregulates osteoclastogenesis by reducing ROS production. Therefore, LED irradiation/LLLT might be useful as an alternative, conservative approach to osteoporosis management.


Assuntos
Reabsorção Óssea/etiologia , Terapia com Luz de Baixa Intensidade/instrumentação , Osteoclastos/efeitos da radiação , Ligante RANK/fisiologia , Animais , Reabsorção Óssea/metabolismo , Reabsorção Óssea/patologia , Técnicas de Cultura de Células , Diferenciação Celular/efeitos da radiação , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Osteoclastos/metabolismo , Osteoclastos/patologia
20.
Nanoscale ; 7(30): 12888-94, 2015 Aug 14.
Artigo em Inglês | MEDLINE | ID: mdl-26161911

RESUMO

Lightweight porous ceramic materials that can recover their shapes after mechanical deformation have numerous applications. However, these types of materials tend to be highly fragile and often crack when compressed. Here, we report on the fabrication and characterization of highly porous, freestanding composites of hexagonal boron nitride (h-BN) and single-walled carbon nanotubes (SWCNTs) of density 13-15 mg mL(-1), which corresponds to a volume fraction of 0.009, that were mechanically robust and recovered their original shape even after uniaxially compressing them by more than 50%. We made these porous elastomeric composites using a solution based assembly process that involved first shaping SWCNTs into porous networks of density ∼7 mg mL(-1) (volume fraction ∼0.005) followed by coatings of SWCNT networks with 6-8 mg mL(-1) of h-BN (volume fraction ∼0.003-0.004). The h-BN coating strengthened the underlying SWCNT networks, likely via reinforcement of the nodes between the SWCNTs, resulting in an increase in Young's modulus by ∼100% compared to that of SWCNT networks alone. Surprisingly, SWCNT networks, which were initially highly fragile, became elastomeric after h-BN coating, even though porous structures solely from h-BN are very brittle. Our fabrication approach preserves the morphology of the underlying networks, allowing for fabrication of various shapes and sizes of porous composites of h-BN and SWCNTs. Finally, our fabrication scheme is robust and facile for the preparation of porous composites of diverse ceramic materials and SWCNTs using the appropriate ceramic-precursor.

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