Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 330
Filtrar
1.
Med Devices (Auckl) ; 17: 229-235, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38948076

RESUMO

Purpose: Furoscix® (subcutaneous furosemide) is administered using a wearable On-Body Infusor (OBI) and is approved for the treatment of congestion associated with heart failure (HF). The purpose of this study was to assess the safe and effective use of the OBI and Instructions for Use (IFU) by patients with HF, caregivers, and healthcare practitioners (HCPs). Methods: Sixty participants (patients, n=30; caregivers, n=15; HCPs, n=15) were evaluated on completion of OBI use tasks and IFU knowledge tasks in a simulated use environment. Fifteen of the patients received OBI/IFU training before evaluation. Results: Overall, 893/900 (99.2%) use tasks and 2211/2220 (99.6%) knowledge tasks were completed successfully, without differences due to training. The most common (n=6) use error was failure to wipe skin or cartridge tip with an alcohol wipe. Errors were due to forgetfulness/misinterpretation rather than IFU clarity. Conclusion: The subcutaneous furosemide OBI can be safely and effectively used by patients, caregivers, and HCPs, regardless of training.

3.
World Neurosurg X ; 22: 100282, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38444873

RESUMO

Background/objective: The recent development of minimally invasive surgical techniques (MIS) has made possible the correction of adult spinal deformity (ASD) with less blood loss and shorter hospital stays. However, minimally invasive placement of pedicle screws at the proximal level of the construct can increase pseudarthrosis risk, leading to implant failure, kyphosis, and reoperations. We aggregate existing literature to describe pseudarthrosis rates at the proximal thoracic or thoracolumbar junction in MIS and subsequent reoperation rates. Methods: After a three-tied search strategy in PubMed, we identified 9 articles for study inclusion, describing outcomes from MIS correction of ASD, pseudarthrosis as complication, and surgery on 4+ levels. Baseline patient characteristics and combined rates of pseudarthrosis and reoperation were calculated. Results: A total of 482 patients were studied with an average [range] age of 65.5 [60.4,72], 6.3 [4.4,11] levels fused per patient, follow-up time of 28.3 [12,39] months, and 64.8% females. Pseudarthrosis was reported in 28 of 482 pooled patients (5.8%) of which 15 of 374 pooled patients (4.0%) ultimately underwent a reoperation for pseudarthrosis. Post-operative characteristics included an estimated blood loss (EBL) of 527.1 [241,1466] mL, operating time of 297.9 [183,475] minutes, and length of stay of 7.7 [5,10] days. Among the papers comparing MIS to open surgery, all reported a significantly lower EBL in patients treated with MIS. Conclusion: This analysis demonstrate a measurable pseudarthrosis risk when using MIS to treat ASD, overwhelming requiring reoperation. The benefits of MIS must be considered against the drawbacks of pseudarthrosis when determining ASD management.

4.
J Cerebrovasc Endovasc Neurosurg ; 25(4): 380-389, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-37469029

RESUMO

OBJECTIVE: Middle meningeal artery embolization (MMAe) has burgeoned as a treatment for chronic subdural hematoma (cSDH). This study evaluates the safety and short-term outcomes of MMAe patients relative to traditional treatment approaches. METHODS: In this retrospective large database study, adult patients in the National Inpatient Sample from 2012-2019 with a diagnosis of cSDH were identified. Cost of admission, length of stay (LOS), discharge disposition, and complications were analyzed. Propensity score matching (PSM) was utilized. RESULTS: A total of 123,350 patients with cSDH were identified: 63,450 without intervention, 59,435 surgery only, 295 MMAe only, and 170 surgery plus MMAe. On PSM analysis, MMAe did not increase the risk of inpatient complications or prolong the length of stay compared to conservative management (p>0.05); MMAe had higher cost ($31,170 vs. $10,768, p<0.001) than conservative management, and a lower rate of nonroutine discharge (53.8% vs. 64.3%, p=0.024). Compared to surgery, MMAe had shorter LOS (5 vs. 7 days, p<0.001), and lower rates of neurological complications (2.7% vs. 7.1%, p=0.029) and nonroutine discharge (53.8% vs. 71.7%, p<0.001). There was no significant difference in cost (p>0.05). CONCLUSIONS: MMAe had similar LOS and decreased odds of adverse discharge with a modest cost increase compared to conservative management. There was no difference in inpatient complications. Compared to surgery, MMAe treatment was associated with decreased LOS and rates of neurological complications and nonroutine discharge. This nationwide analysis supports the safety of MMAe to treat cSDH.

5.
World Neurosurg ; 2023 Jul 05.
Artigo em Inglês | MEDLINE | ID: mdl-37419313

RESUMO

BACKGROUND: The San Diego-Mexico border wall height extension is associated with increased traumatic injuries and related costs after wall falls. We report previous trends and a neurological injury type not previously associated with border falls: blunt cerebrovascular injuries (BCVIs). METHODS: In this retrospective cohort study, patients who presented to the UC San Diego Health Trauma Center for injuries from border wall falls from 2016 to 2021 were considered. Patients were included if they were admitted before (January 2016 to May 2018) or after (January 2020 to December 2021) the height extension period. Patient demographics, clinical data, and hospital stay data were compared. RESULTS: We identified 383 patients, 51 (68.6% male; mean age, 33.5 years) in the pre-height extension cohort and 332 (77.1% male; mean age, 31.5 years) in the post-height extension cohort. There were 0 and 5 BCVIs in the pre- and post-height extension groups, respectively. BCVIs were associated with increased injury severity scores (9.16 vs. 31.33; P < 0.001), longer intensive care unit lengths of stay (median, 0 days; [interquartile range (IQR), 0-3 days]; vs. median, 5 days [IQR, 2-21 days]; P = 0.022), and increased total hospital charges (median, $163,490 [IQR, $86,578-$282,036]; vs. median, $835,260 [IQR, $171,049-$1,933,996]; P = 0.048). Poisson modeling found BCVI admissions were 0.21 (95% confidence interval, 0.07-0.41; P = 0.042) per month higher after the height extension. CONCLUSIONS: We review the injuries correlating with the border wall extension and reveal an association with rare, potentially devastating BCVIs that were not seen before the border wall modifications. These BCVIs and associated morbidity shed light on the trauma increasingly found at the southern U.S. border, which could be informative for future infrastructure policy decisions.

6.
J Neurosurg ; 139(3): 848-853, 2023 09 01.
Artigo em Inglês | MEDLINE | ID: mdl-36806495

RESUMO

OBJECTIVE: The aim of this study was to investigate the impact of the US-Mexico border wall height extension on traumatic brain injuries (TBIs) and related costs. METHODS: In this retrospective cohort study, patients who presented to the UC San Diego Health Trauma Center for injuries from falling at the border wall between 2016 and 2021 were considered. Patients in the pre-height extension period (January 2016-May 2018) were compared with those in the post-height extension period (January 2020-December 2021). Demographic characteristics, clinical data, and hospital charges were analyzed. RESULTS: A total of 383 patients were identified: 51 (0 TBIs, 68.6% male) in the pre-height extension cohort and 332 (14 TBIs, 77.1% male) in the post-height extension cohort, with mean ages of 33.5 and 31.5 years, respectively. There was an increase in the average number of TBIs per month (0.0 to 0.34) and operative TBIs per month (0.0 to 0.12). TBIs were associated with increased Injury Severity Score (8.8 vs 24.2, p < 0.001), median (IQR) hospital length of stay (5.0 [2-11] vs 8.5 [4-45] days, p = 0.03), and median (IQR) hospital charges ($163,490 [$86,369-$277,918] vs $243,658 [$136,769-$1,127,920], p = 0.04). TBIs were normalized for changing migration rates on the basis of Customs and Border Protection apprehensions. CONCLUSIONS: This heightened risk of intracranial injury among vulnerable immigrant populations poses ethical and economic concerns to be addressed regarding border wall infrastructure.


Assuntos
Lesões Encefálicas Traumáticas , Humanos , Masculino , Feminino , Estudos Retrospectivos , México/epidemiologia , Lesões Encefálicas Traumáticas/epidemiologia , Morbidade , Escala de Gravidade do Ferimento
7.
J Travel Med ; 29(7)2022 11 04.
Artigo em Inglês | MEDLINE | ID: mdl-36165623

RESUMO

BACKGROUND: The recent San Diego-Mexico border wall height extension has resulted in an increased injury risk for unauthorized immigrants falling from greater heights. However, the effects of the border wall extension on frequency and morbidity of spinal injuries and related economic costs have yet to be highlighted. METHODS: We retrospectively compared two cohorts who presented to the UC San Diego Health Trauma Center for border wall falls: pre-height extension (12 patients; January 2016-May 2018), and post-height extension (102 patients; January 2020-December 2021). Patients presented during border wall construction (June 2018-December 2019) were excluded. Demographics, clinical data and hospital costs were collected. Spinal injuries were normalized using Customs and Border Protection apprehensions. Costs were adjusted for inflation using the 2021 medical care price index. RESULTS: The increase in spine injuries per month (0.8-4.25) and operative spine injuries per month (0.3- 1.7) was statistically significant (P < 0.001). Increase in median length of stay from 6 [interquartile range (IQR) 2-7] to 9 days (IQR 6-13) was statistically significant (P = 0.006). Median total hospital charges increased from $174 660 to $294 421 and was also significant (P < 0.001). CONCLUSION: The data support that the recent San Diego-Mexico border wall extension is correlated with more frequent, severe and costly spinal injuries. This current infrastructure should be re-evaluated as border-related injuries represent a humanitarian and public health crisis.


Assuntos
Traumatismos da Coluna Vertebral , Humanos , Estudos Retrospectivos , México/epidemiologia , Traumatismos da Coluna Vertebral/epidemiologia
8.
Artigo em Inglês | MEDLINE | ID: mdl-34788723

RESUMO

Immobilized metal affinity chromatography (IMAC) is a well-established technique for protein separation and purification. IMAC has been previously utilized to capture the malaria biomarker histidine-rich protein 2 (HRP2) from blood, enhancing the sensitivity of field-appropriate diagnostic tools such as lateral flow assays. However, little work has been done to translate this technique to a truly field-usable design. In this study, IMAC-functionalized cellulose membranes are created and characterized fully for future use in applied malaria diagnostics. IMAC-functionalized cellulose membranes were investigated across a range of cellulose substrates, IMAC ligands, and divalent transition metals before use in a capture and elution flowthrough workflow. Following characterization and optimization, it was found that iminodiacetic acid bound to Zn(II) was the most promising ligand-metal pair, with three available coordination sites and a molar loading capacity of 57.7 µmol of metal/cm3 of cellulose. Using these parameters, more than 99% of HRP2 was captured from a large-volume lysed blood sample in a simple flow-through assay and 89% of the captured protein was eluted from the membrane using the chelating compound ethylenediaminetetraacetic acid. Use of this enhancement protocol on an in-house HRP2 lateral flow assay (LFA) yielded a limit of detection of 7 parasites/µL, a 15.8x enhancement factor compared to traditional LFA methods.


Assuntos
Antígenos de Protozoários/sangue , Celulose/química , Cromatografia de Afinidade/métodos , Malária/diagnóstico , Testes Imediatos , Proteínas de Protozoários/sangue , Zinco/química , Antígenos de Protozoários/metabolismo , Cromatografia de Afinidade/instrumentação , Humanos , Ligantes , Malária/sangue , Malária/parasitologia , Plasmodium falciparum/metabolismo , Proteínas de Protozoários/metabolismo
10.
Ir Med J ; 112(2): 874, 2019 02 14.
Artigo em Inglês | MEDLINE | ID: mdl-30875167

RESUMO

Aim Report successful application of UV endonasal phototherapy as a treatment for severe rhinitis medicamentosa and allergic rhinitis. Methods Allergic rhinitis confirmed by history and skin prick testing; rhinitis medicamentosa based on history. Both confirmed at nasendoscopy. Symptom score before & after treatment. Introduction of Rhinolight endonasal u/v phototherapy for allergic rhinitis. Single patient report. Results Successful remission of Rhinitis Medicamentosa confirmed with patient after eight sessions Rhinolight endonasal phototherapy. Use of nasal decongestant dropped from 2 bottles/daily x 4 years to zero. Symptoms reduced from 25 pre-treatment to 6 post-treatment. Rhinitis medicamentosa is clinically characterized by nasal congestion without rhinorrhea, postnasal drip, or sneezing that begins after using a nasal decongestant for more than 3 days. Treatment involves discontinuation of the offending drug. Discussion Rhinolight endonasal phototherapy is a new treatment for allergic rhinitis and offered as last resort for a patient with untreated allergic rhinitis and overuse of topical decongestants. Patient reports a significant improvement in symptoms with cessation of topical decongestant. Report a successful application of UV endonasal phototherapy as a treatment for severe rhinitis medicamentosa against a background of long standing allergic rhinitis.


Assuntos
Descongestionantes Nasais/efeitos adversos , Rinite Alérgica/induzido quimicamente , Rinite Alérgica/radioterapia , Terapia Ultravioleta/métodos , Adulto , Humanos , Masculino , Descongestionantes Nasais/administração & dosagem , Mucosa Nasal/patologia , Sprays Nasais , Rinite Alérgica/patologia , Índice de Gravidade de Doença , Resultado do Tratamento
11.
Chem Rev ; 119(2): 1456-1518, 2019 01 23.
Artigo em Inglês | MEDLINE | ID: mdl-30511833

RESUMO

Infectious diseases claim millions of lives each year. Robust and accurate diagnostics are essential tools for identifying those who are at risk and in need of treatment in low-resource settings. Inorganic complexes and metal-based nanomaterials continue to drive the development of diagnostic platforms and strategies that enable infectious disease detection in low-resource settings. In this review, we highlight works from the past 20 years in which inorganic chemistry and nanotechnology were implemented in each of the core components that make up a diagnostic test. First, we present how inorganic biomarkers and their properties are leveraged for infectious disease detection. In the following section, we detail metal-based technologies that have been employed for sample preparation and biomarker isolation from sample matrices. We then describe how inorganic- and nanomaterial-based probes have been utilized in point-of-care diagnostics for signal generation. The following section discusses instrumentation for signal readout in resource-limited settings. Next, we highlight the detection of nucleic acids at the point of care as an emerging application of inorganic chemistry. Lastly, we consider the challenges that remain for translation of the aforementioned diagnostic platforms to low-resource settings.


Assuntos
Doenças Transmissíveis/diagnóstico , Complexos de Coordenação/química , Metais/química , Nanoestruturas/química , Biomarcadores/análise , Humanos , Medições Luminescentes/métodos , Magnetismo , Sistemas Automatizados de Assistência Junto ao Leito
12.
J Med Entomol ; 54(3): 712-718, 2017 05 01.
Artigo em Inglês | MEDLINE | ID: mdl-28069630

RESUMO

Arthropod-borne diseases negatively affect humans worldwide. Understanding the biology of the arthropod vectors and the pathogens they harbor, the arthropods are moving targets as a result of climate change, ecosystem degradation, species introductions, and increased human travel. Viruses within the California serogroup of the genus Orthobunyavirus (family Bunyaviridae) are among the mosquito-borne viruses of concern owing to their zoonotic potential. Two of these, snowshoe hare virus (SSHV) and Jamestown Canyon virus, were shown, using a combination of serology and virus isolations, to circulate on the Island of Newfoundland, Canada, in the 1980s. More recently, serological analysis demonstrated that these two viruses continue to circulate on the Island in several domesticated and wild animals. Here, we detected the seroconversion to SSHV in wild snowshoe hares and in a single sentinel rabbit. The seroconversion in the sentinel rabbit occurred in early August (2011), which corresponded to the weeks of peak mosquito collections and the timing of the detection of SSHV in suspected mosquito vectors. A portion of the SSHV S segment sequence was generated from mosquito pools collected at sites near the sentinel rabbits and phylogenetically analyzed using the neighbor-joining method with other available California serogroup virus sequences. This analysis validated the SSHV identification but showed that the Newfoundland sequence fell outside the other SSHV sequences available, which originated from the United States between 1959 and 2005.


Assuntos
Culicidae/virologia , Vírus da Encefalite da Califórnia/fisiologia , Encefalite da Califórnia/transmissão , Lebres , Insetos Vetores/virologia , Animais , Encefalite da Califórnia/virologia , Terra Nova e Labrador , Estações do Ano
13.
J Med Entomol ; 53(6): 1364-1369, 2016 11.
Artigo em Inglês | MEDLINE | ID: mdl-27592550

RESUMO

Culex pipiens L., the northern house mosquito, is the primary vector of West Nile virus to humans along the east coast of North America and thus the focus of much study. This species is an urban container-breeding mosquito whose close contact with humans and flexibility in host choice has led to its classification as a "bridge vector"; that is, it is thought to move zoonotic diseases to humans from vertebrate reservoirs. While this invasive species is now well documented in its established range, which expanded in 2001 to include Canada, the existence of populations of this species along the fringes of its range are less well known. Here we report, using morphological and genetic techniques, the existence of two locations where Cx. pipiens exists in Newfoundland in both expected and unexpected sites based on projected habitat suitability on the island.


Assuntos
Distribuição Animal , Culex/fisiologia , Insetos Vetores/fisiologia , Animais , Culex/anatomia & histologia , Culex/genética , Complexo IV da Cadeia de Transporte de Elétrons/genética , Proteínas de Insetos/genética , Espécies Introduzidas , Terra Nova e Labrador , Febre do Nilo Ocidental/transmissão
14.
Hosp Pharm ; 49(8): 713-6, 2014 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-25477596

RESUMO

Sound precepting skills are vitally important for all pharmacists and for the future of our profession. Residency training provides a fertile environment for the resident to learn and foster new skills. This article outlines an accelerated model for developing precepting skills in residents and provides helpful advice for residents seeking to gain experience as a preceptor.

15.
Epidemiol Infect ; 141(3): 591-5, 2013 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-22640592

RESUMO

West Nile virus (WNV) was first recognized in the USA in 1999. We estimated the cumulative incidence of WNV infection in the USA from 1999 to 2010 using recently derived age- and sex-stratified ratios of infections to WNV neuroinvasive disease (WNND) and the number of WNND cases reported to national surveillance. We estimate that over 3 million persons have been infected with WNV in the USA, with the highest incidence rates in the central plains states. These 3 million infections would have resulted in about 780 000 illnesses. A substantial number of WNV infections and illnesses have occurred during the virus' first decade in the USA.


Assuntos
Febre do Nilo Ocidental/epidemiologia , Vírus do Nilo Ocidental , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Incidência , Masculino , Pessoa de Meia-Idade , Estados Unidos/epidemiologia , Adulto Jovem
16.
Transfus Med ; 22(1): 68-70, 2012 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-22171556

RESUMO

OBJECTIVE: To assess if a modified thrombin clotting time test could be used as a simple quality control (QC) method to screen for unfractionated heparin in the product obtained from obstetric intraoperative cell salvage cases before re-infusion. BACKGROUND: A national QC scheme has recently been piloted to monitor the quality of autologous blood being returned to the patient. Laboratory tests include full blood count and microalbumin. Unfractionated heparin testing should be performed to ensure that there is no gross contamination of heparin in the final product; however, presently, there is no quick cheap test available suitable for heparin detection. MATERIALS AND METHODS: Samples were collected into plain non-anticoagulated tubes and centrifuged at 2500 × g for 5 min. Supernatant was mixed with commercially available coagulated normal plasma and a thrombin clotting time test performed. RESULTS: Calibration runs demonstrated that our system was sensitive up to 0 · 14 IU mL(-1) heparin, linear between 0 · 08 and 0 · 14 IU mL(-1). CONCLUSION: We have shown that the thrombin clotting time test can be modified and used as a cheap and reliable marker for heparin contamination. We have successfully incorporated this modified test into our hospital's obstetric QC scheme.


Assuntos
Anticoagulantes/farmacologia , Heparina/farmacologia , Procedimentos Cirúrgicos Obstétricos , Tempo de Trombina/métodos , Tempo de Trombina/normas , Adulto , Perda Sanguínea Cirúrgica/prevenção & controle , Calibragem , Feminino , Humanos , Período Intraoperatório , Controle de Qualidade
17.
Med Phys ; 39(6Part21): 3869-3870, 2012 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-28518282

RESUMO

Ultrasound system standards and professional guidelines can facilitate efficient provision of medical physics services and growth of ultrasound imaging if the documents are well designed and are utilized. We too often develop our own phantoms and procedures and never converge to obtain a critical mass of data on system performance and value of such services. Standards can also produce unnecessary costs and limit innovation if not carefully developed, reviewed, and changed as needed. There are quite a few new initiatives that, if followed vigorously, could improve medical ultrasound and medical physicists' contributions thereto. This talk is to explain many of the existing standards and recommendations for ultrasound system quality control, performance evaluation, and safety, as well as current and suggested efforts in these areas. The primary standards body for medical ultrasound systems is now the International Electrotechnical Commission (IEC). Uniformity across the world is helpful to all if the documents are reasonably current. There still is a role for traditional bodies such as the AAPM with its valuable report series and the American Inst. of Ultras. in Med. (AIUM) with its own standards and reports and its joint work with the Medical Imaging Technology Alliance (MITA). All three, with strong involvement of FDA scientists and with some efforts from the Acoustical Society of America have historically provided the main standards affecting medical physicists. Now that the lengthy IEC process is moving more smoothly, our national bodies still can provide new developments and drafts that can be offered as needed for international standardization. The ACR in particular can provide meaningful incentives through ultrasound service accreditation. Without any regulatory or strong consumer push, reports and standards on ultrasound system performance have received only modest use in the USA. A consistent consumer or accreditation push might be justified now. A series of three standards on performance evaluation is well on its way to covering pulse echo ultrasound well, with IEC 61319-1 on spatial measurements, IEC 61319-2 on depth of penetration and local dynamic range and one draft and one Technical Specification 62558 on small void imaging. A new effort has just been initiated to help drive more and better use of quantitative ultrasound imaging in human and surrogate studies and in clinical use. A shear wave speed ultrasound technical committee will carry out this effort in the Quantitative Imaging Biomarkers Alliance (QIBA) that is managed by the RSNA. LEARNING OBJECTIVES: 1. Understand the coverage of the two current and third planned IEC medical ultrasound performance evaluation standards that could form a basis for stable performance evaluation tests. 2. Understand the coverage of the Current AIUM and ACR QC documents and the drafting and support efforts in the IEC. 3. Understand the need for and partial availability of simplified software and instructions to improve and facilitate performance of these tests? 4. Understand how standards development can lead to improved understanding and performance of medical ultrasound imaging as is anticipated for the new QIBA effort.

18.
Ultrasound Med Biol ; 36(10): 1691-703, 2010 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-20800939

RESUMO

Acoustic droplet vaporization (ADV) shows promise for spatially and temporally targeted tissue occlusion. In this study, substantial tissue occlusion was achieved in operatively exposed and transcutaneous canine kidneys by generating ADV gas bubbles in the renal arteries or segmental arteries. Fifteen canines were anesthetized, among which 10 underwent laparotomy to externalize the left kidney and five were undisturbed for transcutaneous ADV. The microbubbles were generated by phase conversion of perfluoropentane droplets encapsulated in albumin or lipid shells in the blood. A 3.5-MHz single-element therapy transducer was aligned with an imaging array in a water tank with direct access to the renal artery or a segmental artery. In vivo color flow and spectral Doppler imaging were used to identify the target arteries. Tone bursts of 1 kHz pulse repetition frequency with 0.25% duty cycle vaporized the droplets during bolus passage. Both intracardiac (IC) and intravenous (IV) injections repeatedly produced ADV in chosen arteries in externalized kidneys, as seen by B-mode imaging. Concurrent with this in two cases was the detection by pulse-wave Doppler of blood flow reversal, along with a narrowing of the waveform. Localized cortex occlusion was achieved with 87% regional flow reduction in one case using IC injections. Vaporization from IV injections resulted in a substantial echogenicity increase with an average half-life of 8 min per droplet dose. Gas bubbles sufficient to produce some shadowing were generated by transcutaneous vaporization of intrarenal artery or IV-administered droplets, with a tissue path up to 5.5 cm.


Assuntos
Embolização Terapêutica/métodos , Artéria Renal/diagnóstico por imagem , Ultrassom/métodos , Acústica , Animais , Cães , Estudos de Viabilidade , Microbolhas , Circulação Renal , Sonicação/métodos , Ultrassonografia Doppler/métodos , Ultrassonografia Doppler em Cores/métodos , Volatilização
19.
Ultrasound Med Biol ; 35(5): 813-28, 2009 May.
Artigo em Inglês | MEDLINE | ID: mdl-19345468

RESUMO

Previous studies indicate imaging of ultrasound contrast in 3-D is potentially superior to 2-D imaging for vascular characterization. A dual-beam, dynamic refill technique, which relies on volumetric contrast clearance and sequential imaging, was used to image a preserved porcine kidney perfused with contrast. A model was developed for the contrast profile across the renal artery to estimate fractional blood volume. This model was used along with refill curve information to measure absolute perfusion within renal cortex for a 100-cm(3) volume. Perfusion measurements from a slice within the volume were also made using a modified interval imaging technique. The measured perfusion using the dual-beam technique was consistent with the perfusion measured using the interval imaging technique (dual-beam values were 1.06 +/- 0.04 x corresponding interval imaging values). These experiments suggest that ultrasound contrast perfusion measurements are independent of the volume of contrast eliminated before refill.


Assuntos
Imageamento Tridimensional/métodos , Rim/diagnóstico por imagem , Animais , Meios de Contraste/farmacocinética , Modelos Cardiovasculares , Imagens de Fantasmas , Artéria Renal/diagnóstico por imagem , Circulação Renal , Sus scrofa , Transdutores , Ultrassonografia
20.
Rev Sci Instrum ; 79(6): 063904, 2008 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-18601414

RESUMO

Optical nuclear magnetic resonance (ONMR) is a powerful probe of electronic properties in III-V semiconductors. Larmor-beat detection (LBD) is a sensitivity optimized, time-domain NMR version of optical detection based on the Hanle effect. Combining LBD ONMR with the line-narrowing method of POWER (perturbations observed with enhanced resolution) NMR further enables atomically detailed views of local electronic features in III-Vs. POWER NMR spectra display the distribution of resonance shifts or line splittings introduced by a perturbation, such as optical excitation or application of an electric field, that is synchronized with a NMR multiple-pulse time-suspension sequence. Meanwhile, ONMR provides the requisite sensitivity and spatial selectivity to isolate local signals within macroscopic samples. Optical NMR, LBD, and the POWER method each introduce unique demands on instrumentation. Here, we detail the design and implementation of our system, including cryogenic, optical, and radio-frequency components. The result is a flexible, low-cost system with important applications in semiconductor electronics and spin physics. We also demonstrate the performance of our systems with high-resolution ONMR spectra of an epitaxial AlGaAs/GaAs heterojunction. NMR linewidths down to 4.1 Hz full width at half maximum were obtained, a 10(3)-fold resolution enhancement relative any previous optically detected NMR experiment.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...