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1.
Ann Surg Oncol ; 30(13): 7976-7985, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-37670120

RESUMO

BACKGROUND: Portal vein embolization (PVE) is used to induce remnant liver hypertrophy prior to major hepatectomy. The purpose of this study was to evaluate the predictive value of baseline computed tomography (CT) data for future remnant liver (FRL) hypertrophy after PVE. METHODS: In this retrospective study, all consecutive patients undergoing right-sided PVE with or without hepatic vein embolization between 2018 and 2021 were included. CT volumetry was performed before and after PVE to assess standardized FRL volume (sFRLV). Radiomic features were extracted from baseline CT after segmenting liver (without tumor), spleen and bone marrow. For selecting features that allow classification of response (hypertrophy ≥ 1.33), a stepwise dimension reduction was performed. Logistic regression models were fitted and selected features were tested for their predictive value. Decision curve analysis was performed on the test dataset. RESULTS: A total of 53 patients with liver tumor were included in this study. sFRLV increased significantly after PVE, with a mean hypertrophy of FRL of 1.5 ± 0.3-fold. sFRLV hypertrophy ≥ 1.33 was reached in 35 (66%) patients. Three independent radiomic features, i.e. liver-, spleen- and bone marrow-associated, differentiated well between responders and non-responders. A logistic regression model revealed the highest accuracy (area under the curve 0.875) for the prediction of response, with sensitivity of 1.0 and specificity of 0.5. Decision curve analysis revealed a positive net benefit when applying the model. CONCLUSIONS: This proof-of-concept study provides first evidence of a potential predictive value of baseline multi-organ radiomics CT data for FRL hypertrophy after PVE.


Assuntos
Embolização Terapêutica , Neoplasias Hepáticas , Humanos , Veia Porta/patologia , Estudos Retrospectivos , Fígado/cirurgia , Hepatectomia/métodos , Neoplasias Hepáticas/cirurgia , Hipertrofia/patologia , Hipertrofia/cirurgia , Resultado do Tratamento
2.
Neuroradiology ; 65(12): 1777-1785, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-37878032

RESUMO

PURPOSE: This study aimed to evaluate the effectiveness and safety of the NeVaTM stent retriever as first- and second-line device for mechanical thrombectomy in acute ischemic stroke. METHODS: In this retrospective single-center study, all consecutive patients that underwent mechanical thrombectomy with NeVaTM stent retriever as first- or second-line device due to intracranial vessel occlusion with acute ischemic stroke between March and November 2022 were included. RESULTS: Thirty-nine patients (m=18, f=21) with a mean age of 69.9 ± 13.3 years were treated with the NeVaTM stent retriever. NeVaTM stent retriever was used as first-line device in 24 (61.5%) of patients and in 15 (38.5%) as second-line device. First-pass rate (≥mTICI 2c) of NeVaTM stent retriever was both 66.7% when used as first- or second-line device. Final recanalization rate including rescue strategies was 92.3% for ≥mTICI2c and 94.9% for ≥mTICI2b. No device-related minor or major adverse events were observed. A hemorrhage was detected in 33.3% of patients at 24h post-thrombectomy dual-energy CT, of which none was classified as symptomatic intracerebral hemorrhage. NIHSS and mRS improved significantly at discharge compared to admission (p<0.05). CONCLUSION: The NeVaTM stent retriever has a high effectivity and good safety profile as first- and second-line device for mechanical thrombectomy in acute ischemic stroke.


Assuntos
Isquemia Encefálica , AVC Isquêmico , Acidente Vascular Cerebral , Humanos , Pessoa de Meia-Idade , Idoso , Idoso de 80 Anos ou mais , Acidente Vascular Cerebral/diagnóstico por imagem , Acidente Vascular Cerebral/cirurgia , Acidente Vascular Cerebral/etiologia , AVC Isquêmico/etiologia , Isquemia Encefálica/diagnóstico por imagem , Isquemia Encefálica/cirurgia , Estudos Retrospectivos , Resultado do Tratamento , Trombectomia , Stents
3.
Sensors (Basel) ; 23(17)2023 Sep 03.
Artigo em Inglês | MEDLINE | ID: mdl-37688083

RESUMO

Nitrate (NO3) pollution in groundwater, caused by various factors both natural and synthetic, contributes to the decline of human health and well-being. Current techniques used for nitrate detection include spectroscopic, electrochemical, chromatography, and capillary electrophoresis. It is highly desired to develop a simple cost-effective alternative to these complex methods for nitrate detection. Therefore, a real-time poly (3,4-ethylenedioxythiophene) (PEDOT)-based sensor for nitrate ion detection via electrical property change is introduced in this study. Vapor phase polymerization (VPP) is used to create a polymer thin film. Variations in specific parameters during the process are tested and compared to develop new insights into PEDOT sensitivity towards nitrate ions. Through this study, the optimal fabrication parameters that produce a sensor with the highest sensitivity toward nitrate ions are determined. With the optimized parameters, the electrical resistance response of the sensor to 1000 ppm nitrate solution is 41.79%. Furthermore, the sensors can detect nitrate ranging from 1 ppm to 1000 ppm. The proposed sensor demonstrates excellent potential to detect the overabundance of nitrate ions in aqueous solutions in real time.

4.
Sensors (Basel) ; 23(15)2023 Aug 03.
Artigo em Inglês | MEDLINE | ID: mdl-37571674

RESUMO

In this work, we introduce a novel approach to model the rain and fog effect on the light detection and ranging (LiDAR) sensor performance for the simulation-based testing of LiDAR systems. The proposed methodology allows for the simulation of the rain and fog effect using the rigorous applications of the Mie scattering theory on the time domain for transient and point cloud levels for spatial analyses. The time domain analysis permits us to benchmark the virtual LiDAR signal attenuation and signal-to-noise ratio (SNR) caused by rain and fog droplets. In addition, the detection rate (DR), false detection rate (FDR), and distance error derror of the virtual LiDAR sensor due to rain and fog droplets are evaluated on the point cloud level. The mean absolute percentage error (MAPE) is used to quantify the simulation and real measurement results on the time domain and point cloud levels for the rain and fog droplets. The results of the simulation and real measurements match well on the time domain and point cloud levels if the simulated and real rain distributions are the same. The real and virtual LiDAR sensor performance degrades more under the influence of fog droplets than in rain.

5.
Sensors (Basel) ; 23(6)2023 Mar 14.
Artigo em Inglês | MEDLINE | ID: mdl-36991824

RESUMO

Measurement performance evaluation of real and virtual automotive light detection and ranging (LiDAR) sensors is an active area of research. However, no commonly accepted automotive standards, metrics, or criteria exist to evaluate their measurement performance. ASTM International released the ASTM E3125-17 standard for the operational performance evaluation of 3D imaging systems commonly referred to as terrestrial laser scanners (TLS). This standard defines the specifications and static test procedures to evaluate the 3D imaging and point-to-point distance measurement performance of TLS. In this work, we have assessed the 3D imaging and point-to-point distance estimation performance of a commercial micro-electro-mechanical system (MEMS)-based automotive LiDAR sensor and its simulation model according to the test procedures defined in this standard. The static tests were performed in a laboratory environment. In addition, a subset of static tests was also performed at the proving ground in natural environmental conditions to determine the 3D imaging and point-to-point distance measurement performance of the real LiDAR sensor. In addition, real scenarios and environmental conditions were replicated in the virtual environment of a commercial software to verify the LiDAR model's working performance. The evaluation results show that the LiDAR sensor and its simulation model under analysis pass all the tests specified in the ASTM E3125-17 standard. This standard helps to understand whether sensor measurement errors are due to internal or external influences. We have also shown that the 3D imaging and point-to-point distance estimation performance of LiDAR sensors significantly impacts the working performance of the object recognition algorithm. That is why this standard can be beneficial in validating automotive real and virtual LiDAR sensors, at least in the early stage of development. Furthermore, the simulation and real measurements show good agreement on the point cloud and object recognition levels.

6.
Pneumologie ; 77(8): 461-543, 2023 Aug.
Artigo em Alemão | MEDLINE | ID: mdl-37406667

RESUMO

The management of asthma has fundamentally changed during the past decades. The present guideline for the diagnosis and treatment of asthma was developed for respiratory specialists who need detailed and evidence-based information on the new diagnostic and therapeutic options in asthma. The guideline shows the new role of biomarkers, especially blood eosinophils and fractional exhaled NO (FeNO), in diagnostic algorithms of asthma. Of note, this guideline is the first worldwide to announce symptom prevention and asthma remission as the ultimate goals of asthma treatment, which can be achieved by using individually tailored, disease-modifying anti-asthmatic drugs such as inhaled steroids, allergen immunotherapy or biologics. In addition, the central role of the treatment of comorbidities is emphasized. Finally, the document addresses several challenges in asthma management, including asthma treatment during pregnancy, treatment of severe asthma or the diagnosis and treatment of work-related asthma.


Assuntos
Antiasmáticos , Asma , Feminino , Gravidez , Humanos , Óxido Nítrico , Asma/terapia , Asma/tratamento farmacológico , Antiasmáticos/uso terapêutico , Biomarcadores , Dessensibilização Imunológica
7.
Eur Radiol ; 32(2): 981-989, 2022 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-34331576

RESUMO

OBJECTIVES: To assess imaging features of primary renal sarcomas in order to better discriminate them from non-sarcoma renal tumors. METHODS: Adult patients diagnosed with renal sarcomas from 1995 to 2018 were included from 11 European tertiary referral centers (Germany, Belgium, Turkey). Renal sarcomas were 1:4 compared to patients with non-sarcoma renal tumors. CT/MRI findings were assessed using 21 predefined imaging features. A random forest model was trained to predict "renal sarcoma vs. non-sarcoma renal tumors" based on demographics and imaging features. RESULTS: n = 34 renal sarcomas were included and compared to n = 136 non-sarcoma renal tumors. Renal sarcomas manifested in younger patients (median 55 vs. 67 years, p < 0.01) and were more complex (high RENAL score complexity 79.4% vs. 25.7%, p < 0.01). Renal sarcomas were larger (median diameter 108 vs. 43 mm, p < 0.01) with irregular shape and ill-defined margins, and more frequently demonstrated invasion of the renal vein or inferior vena cava, tumor necrosis, direct invasion of adjacent organs, and contact to renal artery or vein, compared to non-sarcoma renal tumors (p < 0.05, each). The random forest algorithm yielded a median AUC = 93.8% to predict renal sarcoma histology, with sensitivity, specificity, and positive predictive value of 90.4%, 76.5%, and 93.9%, respectively. Tumor diameter and RENAL score were the most relevant imaging features for renal sarcoma identification. CONCLUSION: Renal sarcomas are rare tumors commonly manifesting as large masses in young patients. A random forest model using demographics and imaging features shows good diagnostic accuracy for discrimination of renal sarcomas from non-sarcoma renal tumors, which might aid in clinical decision-making. KEY POINTS: • Renal sarcomas commonly manifest in younger patients as large, complex renal masses. • Compared to non-sarcoma renal tumors, renal sarcomas more frequently demonstrated invasion of the renal vein or inferior vena cava, tumor necrosis, direct invasion of adjacent organs, and contact to renal artery or vein. • Using demographics and standardized imaging features, a random forest showed excellent diagnostic performance for discrimination of sarcoma vs. non-sarcoma renal tumors (AUC = 93.8%, sensitivity = 90.4%, specificity = 76.5%, and PPV = 93.9%).


Assuntos
Neoplasias Renais , Sarcoma , Neoplasias de Tecidos Moles , Adulto , Humanos , Neoplasias Renais/diagnóstico por imagem , Imageamento por Ressonância Magnética , Sarcoma/diagnóstico por imagem , Veia Cava Inferior
8.
Sensors (Basel) ; 22(17)2022 Aug 26.
Artigo em Inglês | MEDLINE | ID: mdl-36080914

RESUMO

In this paper, we investigate the application of using software-defined radio (SDR) and surface acoustic wave (SAW) device for wireless measurement of the response of in situ sensors. SDR uses software to realize different communication functions. After collecting the magnitude and phase of the response at discrete frequencies, we apply inverse Fourier transform to analyze the time domain responses which, in turn, allows for monitoring the changes of the response of the in situ sensor. We employ microwave signal flow graph concepts to improve the quality of the received signals. Comparing the normalized results obtained by SDR with those obtained from a commercial vector network analyzer (VNA), we demonstrate that the results are sufficiently close, and the SDR-based experiments can provide satisfactory measurement of the in-situ sensors. The objective is to eventually employ this wireless measurement system for soil nutrient sensing.


Assuntos
Software , Tecnologia sem Fio
9.
Sensors (Basel) ; 22(7)2022 Apr 03.
Artigo em Inglês | MEDLINE | ID: mdl-35408380

RESUMO

Passive radar is a technology that has huge potential for airspace monitoring, taking advantage of existing transmissions. However, to predict whether particular targets can be measured in a particular scenario, it is necessary to be able to model the received signal. In this paper, we present the results of a campaign in which a Pilatus PC-12 single-engine aircraft was measured with a passive radar system relying on DVB-T transmission from a single transmitter. We then present our work to simulate the bistatic RCS of the aircraft along its flight track, using both the method of moments and the shooting and bouncing ray solvers, assess the uncertainty in the simulations, and compare against the measurements. We find that our simulated RCS values are useful in predicting whether or not detection occurs. However, we see poor agreement between simulated and measured RCS values where measurements are available, which we attribute primarily to the difficulties in extracting RCS measurements from the data and to unmodeled transmission and received path effects.

10.
Sensors (Basel) ; 22(19)2022 Oct 05.
Artigo em Inglês | MEDLINE | ID: mdl-36236655

RESUMO

This work introduces a process to develop a tool-independent, high-fidelity, ray tracing-based light detection and ranging (LiDAR) model. This virtual LiDAR sensor includes accurate modeling of the scan pattern and a complete signal processing toolchain of a LiDAR sensor. It is developed as a functional mock-up unit (FMU) by using the standardized open simulation interface (OSI) 3.0.2, and functional mock-up interface (FMI) 2.0. Subsequently, it was integrated into two commercial software virtual environment frameworks to demonstrate its exchangeability. Furthermore, the accuracy of the LiDAR sensor model is validated by comparing the simulation and real measurement data on the time domain and on the point cloud level. The validation results show that the mean absolute percentage error (MAPE) of simulated and measured time domain signal amplitude is 1.7%. In addition, the MAPE of the number of points Npoints and mean intensity Imean values received from the virtual and real targets are 8.5% and 9.3%, respectively. To the author's knowledge, these are the smallest errors reported for the number of received points Npoints and mean intensity Imean values up until now. Moreover, the distance error derror is below the range accuracy of the actual LiDAR sensor, which is 2 cm for this use case. In addition, the proving ground measurement results are compared with the state-of-the-art LiDAR model provided by commercial software and the proposed LiDAR model to measure the presented model fidelity. The results show that the complete signal processing steps and imperfections of real LiDAR sensors need to be considered in the virtual LiDAR to obtain simulation results close to the actual sensor. Such considerable imperfections are optical losses, inherent detector effects, effects generated by the electrical amplification, and noise produced by the sunlight.

11.
J Vasc Interv Radiol ; 32(2): 262-269, 2021 02.
Artigo em Inglês | MEDLINE | ID: mdl-33139185

RESUMO

PURPOSE: To evaluate time-driven activity-based costing (TDABC) in interventional radiology for image-guided vascular malformation treatment as an example. MATERIALS AND METHODS: Retrospective analysis was performed on consecutive vascular malformation treatment cycles [67 venous malformations (VMs) and 11 arteriovenous malformations (AVMs)] in a university hospital in 2018. All activities were integrated with a process map, and spent resources were assigned accordingly. TDABC uses 2 parameters: (i) practical capacity cost rate, calculated as 80% of theoretical capacity, and (ii) time consumption of each resource determined by interviews (23 items). Thereby, the total costs were calculated. Treatment cycles were modified according to identified resource waste and TDABC-guided negotiations with health insurance. RESULTS: Total personnel time required was higher for AVM (1,191 min) than for VM (637 min) treatment. The interventional procedure comprised the major part (46%) of personnel time required in AVM, whereas it comprised 19% in VM treatment. Materials represented the major cost type in AVM (75%) and VM (45%) treatments. TDABC-based treatment process modification led to a decrease in personnel time need of 16% and 30% and a cost reduction of 5.5% and 15.7% for AVM and VM treatments, respectively. TDABC-guided cost reduction and TDABC-informed negotiations improved profit from -56% to +40% and from +41% to +69% for AVM and VM treatments, respectively. CONCLUSIONS: TDABC facilitated the precise costing of interventional radiologic treatment cycles and optimized internal processes, cost reduction, and revenues. Hence, TDABC is a promising tool to determine the denominator of interventional radiology's value.


Assuntos
Atenção à Saúde/economia , Custos Hospitalares , Hospitais Universitários/economia , Avaliação de Processos e Resultados em Cuidados de Saúde/economia , Radiografia Intervencionista/economia , Malformações Vasculares/economia , Malformações Vasculares/terapia , Redução de Custos , Análise Custo-Benefício , Humanos , Melhoria de Qualidade/economia , Indicadores de Qualidade em Assistência à Saúde/economia , Estudos Retrospectivos , Fatores de Tempo , Malformações Vasculares/diagnóstico por imagem , Fluxo de Trabalho , Carga de Trabalho/economia
12.
J Vasc Interv Radiol ; 32(10): 1425-1434.e2, 2021 10.
Artigo em Inglês | MEDLINE | ID: mdl-34293437

RESUMO

PURPOSE: To evaluate the safety and effectiveness of combined transarterial embolization and percutaneous sclerotherapy in the treatment of refractory and nonresectable aneurysmal bone cysts (ABCs) as assessed by imaging and clinical outcomes. MATERIALS AND METHODS: This retrospective, single-center study included 16 consecutive patients (9 women and 7 men; median age, 17 years [range, 6-25 years]) who underwent combined transarterial embolization (using ethylene vinyl alcohol) and percutaneous sclerotherapy (using ethanol gel and polidocanol) for refractory and nonresectable ABCs. The median follow-up was 27.3 months (range, 6.7-47.5 months). Grade of mineralization (5-point Likert scale), grade of fluid-fluid levels (FFLs; 4-point Likert scale), and contrast-enhancing lesion volume were evaluated before and after treatment. The quality of life was determined before and after treatment using the Musculoskeletal Tumor Society (MSTS) score and the 36-Item Short Form Survey (SF-36) health questionnaire. RESULTS: A mean of 1.6 ± 0.7 transarterial embolizations and 3.2 ± 1.7 percutaneous sclerotherapies were performed. No adverse events were observed. All patients showed either partial or complete response; no patient showed ABC recurrence. The grade of mineralization (3.7 ± 0.7 after therapy vs 1.4 ± 0.5 at baseline; P < .0001) and grade of FFL (3.5 ± 0.8 after therapy vs 1.9 ± 0.6 at baseline; P < .0001) significantly improved after therapy compared with baseline. The mean contrast-enhancing lesion volume significantly decreased after treatment compared with baseline (45.9 mm³ ± 96.1 vs 156.0 mm³ ± 115.3, respectively; P = .0003). The MSTS scores (28.8 ± 1.8 after treatment vs 14.1 ± 8.6 at baseline; P < .0001) and SF-36 findings revealed a significant improvement in the quality of life after treatment compared with baseline, leaving most patients without relevant constraints. CONCLUSIONS: Combined transarterial embolization and percutaneous sclerotherapy is a minimally invasive, safe, and effective treatment option for refractory and nonresectable ABCs. Treatment fostered bone mineralization and significantly improved patients' quality of life.


Assuntos
Cistos Ósseos Aneurismáticos , Escleroterapia , Adolescente , Cistos Ósseos Aneurismáticos/tratamento farmacológico , Cistos Ósseos Aneurismáticos/terapia , Feminino , Humanos , Masculino , Polidocanol , Qualidade de Vida , Estudos Retrospectivos , Soluções Esclerosantes/uso terapêutico , Escleroterapia/efeitos adversos , Resultado do Tratamento
13.
Dig Dis ; 39(4): 351-357, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33142291

RESUMO

BACKGROUND: Metastatic colorectal cancer (mCRC) is associated with different molecular biology, clinical characteristics, and outcome depending on the primary tumor localization. We aimed to evaluate the effectiveness of 90Y-radioembolization (RE) for therapy of colorectal liver metastases depending on the primary tumor side. METHODS: We performed a retrospective analysis of n = 73 patients with mCRC and RE in our university liver center between 2009 and 2018. Patients were stratified according to the primary tumor side (left vs. right hemicolon), treatment response was assessed by the Response Evaluation Criteria in Solid Tumors (RECIST) at follow-up after 3 months. Kaplan-Meier analysis was performed to analyze survival followed by Cox regression to determine independent prognostic factors for survival. RESULTS: Prior to RE, all patients had received systemic therapy, with either stable or progressive disease, but no partial or complete response. In n = 22/73 (30.1%) patients, the primary tumor side was in the right colon; in n = 51/73 (69.9%) patients, in the left colon. Hepatic tumor burden was ≤25% in n = 36/73 (49.3%) patients and >25% in n = 37/73 (50.7%) patients. At 3 months, n = 21 (33.8%) patients showed treatment response (n = 2 [3.2%]; complete response, n = 19 [30.6%]; partial response), n = 13 (21.0%) stable disease, and n = 28 (45.2%) progressive disease after RE. The median survival in case of primary tumor side in the left colon was significantly higher than for primary tumors in the right colon (8.7 vs. 6.0 months, p = 0.033). The median survival for a hepatic tumor burden ≤25% was significantly higher than that of >25% (13.9 vs. 4.3 months, p < 0.001). The median overall survival was 6.1 months. CONCLUSION: The median survival after RE in hepatic-mCRC depends on the primary tumor side and the preprocedural hepatic tumor burden.


Assuntos
Neoplasias Colorretais/terapia , Embolização Terapêutica/métodos , Neoplasias Hepáticas/terapia , Radioisótopos de Ítrio/uso terapêutico , Adulto , Idoso , Idoso de 80 Anos ou mais , Neoplasias Colorretais/mortalidade , Neoplasias Colorretais/patologia , Embolização Terapêutica/mortalidade , Feminino , Humanos , Estimativa de Kaplan-Meier , Neoplasias Hepáticas/mortalidade , Neoplasias Hepáticas/secundário , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Taxa de Sobrevida , Resultado do Tratamento , Carga Tumoral
14.
Z Gastroenterol ; 59(1): 35-42, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33429448

RESUMO

PURPOSE: To analyze safety and effectiveness of simultaneous portal and hepatic vein embolization (PHVE) or sequential hepatic vein embolization (HVE) compared to portal vein embolization (PVE) for future remnant liver (FRL) hypertrophy prior to major hepatic surgery. METHODS: Patients undergoing PVE, PHVE or HVE at our tertiary care center between 2018 and 2020 were retrospectively included. FRLV, standardized FRLV (sFRLV) and sFRLV growth rate per day were assessed via volumetry, as well as laboratory parameters. RESULTS: 36 patients (f = 15, m = 21; median 64.5 y) were included, 16 patients received PHVE and 20 patients PVE, of which 4 received sequential HVE. Significant increase of FRLV was achieved with both PVE and PHVE compared to baseline (p < 0.0001). sFRLV growth rate did not significantly differ following PHVE (2.2 ±â€Š1.2 %/d) or PVE (2.2 ±â€Š1.7 %/d, p = 0.94). Left portal vein thrombosis (LPVT) was observed after PHVE in 6 patients and in 1 patient after PVE. Sequential HVE showed a considerably high growth rate of 1.42 ±â€Š0.45 %/d after PVE. CONCLUSION: PHVE effectively induces FRL hypertrophy but yields comparable sFRLV to PVE. Sequential HVE further induces hypertrophy after insufficient growth due to PVE. Considering a potentially higher rate of LPVT after PHVE, PVE might be preferred in patients with moderate baseline sFRLV, with optional sequential HVE in non-sufficient responders.


Assuntos
Embolização Terapêutica/métodos , Hepatectomia/métodos , Veias Hepáticas/cirurgia , Veia Porta/cirurgia , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Falência Hepática , Neoplasias Hepáticas/cirurgia , Masculino , Pessoa de Meia-Idade , Complicações Pós-Operatórias , Estudos Retrospectivos , Resultado do Tratamento
15.
Z Gastroenterol ; 59(1): 24-34, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33429447

RESUMO

INTRODUCTION: In the management of patients with decompensated liver cirrhosis, transjugular intrahepatic portosystemic shunt (TIPS) insertion is well-established but common recommendations in the follow up management are inconsistent. Doppler sonography is commonly used for detection for TIPS dysfunction whilst data on the impact of elective invasive examinations are scarce. AIM: The aim of this retrospective analysis is to evaluate potential benefits of elective invasive examinations in the follow up management of patients after TIPS insertion METHODS: Data of all patients receiving TIPS at the university hospitals of Muenster and Bonn between 2013 and 2018 (n = 534) were collected. The impact of performance of elective invasive examinations at 12 months after TIPS insertion on the occurrence of liver related events (LREs) and frequency of TIPS revisions within 24 months after TIPS insertion was analyzed. RESULTS: No significant differences were found concerning occurrence of liver related events after 24 months depending on whether an elective invasive examination was performed. Occurrence of hepatic encephalopathy, relapse of initial indication for TIPS, as well as death or liver transplantation all did not differ. These findings were verified by a subgroup analysis including only patients who did not experience a LRE or TIPS revision within the first 12 months after TIPS procedure. CONCLUSION: The analyzed data suggest no evidence for a beneficial impact due to implementation of an elective invasive examination program after TIPS insertion. Invasive examinations should remain reserved to patients with suspected TIPS dysfunction.


Assuntos
Procedimentos Cirúrgicos Eletivos/efeitos adversos , Varizes Esofágicas e Gástricas/cirurgia , Hipertensão Portal/cirurgia , Derivação Portossistêmica Transjugular Intra-Hepática/efeitos adversos , Varizes Esofágicas e Gástricas/etiologia , Seguimentos , Encefalopatia Hepática , Humanos , Hipertensão Portal/complicações , Derivação Portossistêmica Transjugular Intra-Hepática/estatística & dados numéricos , Estudos Retrospectivos , Resultado do Tratamento
16.
Sensors (Basel) ; 20(11)2020 Jun 10.
Artigo em Inglês | MEDLINE | ID: mdl-32532081

RESUMO

This article presents the statistical analysis of bistatic radar rural ground clutter for different terrain types under low grazing angles. Compared to most state-of-the-art analysis, we present country-specific clutter analysis for subgroups of rural environments rather than for the rural environment as a whole. Therefore, the rural environment analysis is divided into four dominant subgroup terrain types, namely fields with low vegetation, fields with high vegetation, plantations of small trees and forest environments representing a typical rural German environment. We will present the results for both the summer and the winter vegetation. Therefore, bistatic measurement campaigns have been carried out during the summer 2019 and the winter of 2019/20 in the aforementioned four different rural terrain types. The measurements were performed in the radar relevant X-band at a center frequency of 8.85 GHz and over a bandwidth of 100 MHz according to available transmit permission. The distinction of the rural terrain into different subgroups enables a more precise and accurate clutter analysis and modeling of the statistical properties as will be shown in the presented results. The statistical properties are derived from the calculated clutter amplitudes probability density functions and corresponding cumulative distribution functions for each of the four terrain types and the corresponding season. The data basis for the clutter analysis are the processed range-Doppler maps from the bistatic radar measurements. According to the authors' current knowledge, a similar investigation based on real bistatic radar measurement data with the division into terrain subgroups has not yet been carried out and published for a German rural environment.

17.
Sensors (Basel) ; 20(17)2020 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-32882931

RESUMO

Absolute distance measurement is a field of research with a large variety of applications. Laser triangulation is a well-tested and developed technique using geometric relations to calculate the absolute distance to an object. The advantages of laser triangulation include its simple and cost-effective setup with yet a high achievable accuracy and resolution in short distances. A main problem of the technology is that even small changes of the optomechanical setup, e.g., due to thermal expansion, lead to significant measurement errors. Therefore, in this work, we introduce an optical setup containing only a beam splitter and a mirror, which splits the laser into a measurement beam and a reference beam. The reference beam can then be used to compensate for different error sources, such as laser beam dithering or shifts of the measurement setup due to the thermal expansion of the components. The effectiveness of this setup is proven by extensive simulations and measurements. The compensation setup improves the deviation in static measurements by up to 75%, whereas the measurement uncertainty at a distance of 1 m can be reduced to 85 µm. Consequently, this compensation setup can improve the accuracy of classical laser triangulation devices and make them more robust against changes in environmental conditions.

18.
Appl Opt ; 58(13): 3393-3400, 2019 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-31044834

RESUMO

For applications where only moderate spectral resolution is required, static Fourier transform infrared spectrometers (sFTS) offer a comparatively cost-effective alternative to classical scanning instruments. In this paper, we present an sFTS based on a single-mirror interferometer using only standard optical components and an uncooled microbolometer array. Because the instrument features concave mirrors rather than lenses, dispersion effects can be minimized. This enables broadband operation in the mid-infrared range from 2800 cm-1 to 600 cm-1 at a spectral resolution of 12 cm-1. In addition, the design guarantees comparatively high light throughput and can potentially be designed for increased temperature stability. Alongside a simulation of the temperature- and wavenumber-dependent behavior of the system, we provide a proof of principle of the proposed design by means of experimental results.

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