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1.
Clin J Sport Med ; 30(1): e11-e14, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-30908328

RESUMO

A 61-year-old man presented with chronic dorsal foot pain of 9 years that worsened with ambulation. Conventional diagnostic imaging and medical workup were unrevealing, and ankle arthrodesis had been recommended by an orthopedic surgeon for pain relief. Instead, the patient participated in a clinical imaging trial designed for identifying pain generators using whole-body fluorodeoxyglucose (18F-FDG) positron emission tomography/magnetic resonance imaging (PET/MRI). The scan revealed not only high 18F-FDG uptake at the site of pain, but also a hematoma and an inflamed, fibrotic, ruptured plantaris muscle. The fibrotic plantaris likely altered biomechanics with walking, explaining why symptoms worsened with activity. A simple tenotomy of the plantaris tendon was performed to decouple ankle movement from the plantaris injury, resulting in pain relief. This case illustrates the potential of whole-body 18F-FDG PET/MRI to better localize pain generators.

2.
Magn Reson Med ; 81(1): 711-718, 2019 01.
Artigo em Inglês | MEDLINE | ID: mdl-30125389

RESUMO

PURPOSE: To improve the homogeneity and consistency of apparent diffusion coefficient (ADC) estimates in cartilage from the double-echo in steady-state (DESS) sequence by applying SNR-weighted regularization during post-processing. METHODS: An estimation method that linearizes ADC estimates from DESS is used in conjunction with a smoothness constraint to suppress noise-induced variation in ADC estimates. Simulations, phantom scans, and in vivo scans are used to demonstrate how the method reduces ADC variability. Conventional diffusion-weighted echo-planar imaging (DW EPI) maps are acquired for comparison of mean and standard deviation (SD) of the ADC estimate. RESULTS: Simulations and phantom scans demonstrated that the SNR-weighted regularization can produce homogenous ADC maps at varying levels of SNR, whereas non-regularized maps only estimate ADC accurately at high SNR levels. The in vivo maps showed that the SNR-weighted regularization produced ADC maps with similar heterogeneity to maps produced with standard DW EPI, but without the distortion of such reference scans. CONCLUSION: A linear approximation of a simplified model of the relationship between DESS signals allows for fast SNR-weighted regularization of ADC maps that reduces estimation error in relatively short T2 tissue such as cartilage.


Assuntos
Cartilagem/diagnóstico por imagem , Imagem de Difusão por Ressonância Magnética , Imagem Ecoplanar , Interpretação de Imagem Assistida por Computador/métodos , Osteoartrite/diagnóstico por imagem , Razão Sinal-Ruído , Algoritmos , Simulação por Computador , Fêmur/diagnóstico por imagem , Voluntários Saudáveis , Humanos , Processamento de Imagem Assistida por Computador/métodos , Método de Monte Carlo , Imagens de Fantasmas , Reprodutibilidade dos Testes
3.
J Pain Res ; 11: 2353-2357, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30349360

RESUMO

Background: The ability to accurately diagnose and objectively localize pain generators in chronic pain sufferers remains a major clinical challenge since assessment relies on subjective patient complaints and relatively non-specific diagnostic tools. Developments in clinical molecular imaging, including advances in imaging technology and radiotracer design, have afforded the opportunity to identify tissues involved in pain generation based on their pro-nociceptive condition. The sigma-1 receptor (S1R) is a pro-nociceptive receptor upregulated in painful, inflamed tissues, and it can be imaged using the highly specific radioligand 18F-FTC-146 with PET. Case presentation: A 50-year-old woman with a 7-year history of refractory, left-knee pain of unknown origin was referred to our pain management team. Over the past several years, she had undergone multiple treatments, including a lateral retinacular release, radiofrequency ablation of a peripheral nerve, and physical therapy. While certain treatments provided partial relief, her pain would inevitably return to its original state. Using simultaneous positron emission tomography/magnetic resonance imaging (PET/MRI) with the novel radiotracer 18F-FTC-146, imaging showed increased focal uptake of 18F-FTC-146 in the intercondylar notch, corresponding to an irregular but equivocal lesion identified in the simultaneously acquired MRI. These imaging results prompted surgical removal of the lesion, which upon resection was identified as an inflamed, intraarticular synovial lipoma. Removal of the lesion relieved the patient's pain, and to date the pain has not recurred. Conclusion: We present a case of chronic, debilitating knee pain that resolved with surgery following identification of the pathology with a novel clinical molecular imaging approach that detects chronic pain generators at the molecular and cellular level. This approach has the potential to identify and localize pain-associated pathology in a variety of chronic pain syndromes.

4.
J Magn Reson Imaging ; 48(1): 27-47, 2018 07.
Artigo em Inglês | MEDLINE | ID: mdl-29969193

RESUMO

New integrated PET-MRI systems potentially provide a complete imaging modality for diagnosis and evaluation of musculoskeletal disease. MRI is able to provide excellent high-resolution morphologic information with multiple contrast mechanisms that has made it the imaging modality of choice in evaluation of many musculoskeletal disorders. PET offers incomparable abilities to provide quantitative information about molecular and physiologic changes that often precede structural and biochemical changes. In combination, hybrid PET-MRI can enhance imaging of musculoskeletal disorders through early detection of disease as well as improved diagnostic sensitivity and specificity. The purpose of this article is to review emerging applications of PET-MRI in musculoskeletal disease. Both clinical applications of malignant musculoskeletal disease as well as new opportunities to incorporate the molecular capabilities of nuclear imaging into studies of nononcologic musculoskeletal disease are discussed. Lastly, we discuss some of the technical considerations and challenges of PET-MRI as they specifically relate to musculoskeletal disease. LEVEL OF EVIDENCE: 5 TECHNICAL EFFICACY: Stage 3 J. Magn. Reson. Imaging 2018;48:27-47.


Assuntos
Imagem por Ressonância Magnética , Doenças Musculoesqueléticas/diagnóstico por imagem , Tomografia por Emissão de Pósitrons , Adulto , Artrite Reumatoide/diagnóstico por imagem , Doenças Ósseas/diagnóstico por imagem , Osso e Ossos/diagnóstico por imagem , Humanos , Metais , Imagem Multimodal , Mieloma Múltiplo/diagnóstico por imagem , Músculo Esquelético/diagnóstico por imagem , Metástase Neoplásica , Osteoartrite/diagnóstico por imagem , Dor/diagnóstico por imagem , Prognóstico
5.
Muscle Nerve ; 57(3): 494-498, 2018 03.
Artigo em Inglês | MEDLINE | ID: mdl-29211916

RESUMO

INTRODUCTION: Evaluation of the nerve fascicular structure can be useful in diagnosing nerve damage, but it is a very challenging task with 3T MRI because of limited resolution. In this pilot study, we present the feasibility of high-resolution 7T MRI for examining the nerve fascicular structure. METHODS: A 3-dimensional (3D) gradient-spoiled sequence was used for imaging peripheral nerves in extremities. Images acquired with different in-plane resolutions (0.42 × 0.42 mm vs. 0.12 × 0.12 mm), and different main field strengths (7T vs. 3T) were compared. RESULTS: The individual nerve fascicles were identified at 0.12 × 0.12 mm resolution in both field strengths but not at 0.42 × 0.42 mm resolution. The fascicular structure was more sharply depicted in 7T images than in 3T images. DISCUSSION: High-resolution 3D imaging with 7T MRI demonstrated feasibility for imaging nerve fascicular structures. Muscle Nerve 57: 494-498, 2018.


Assuntos
Imagem por Ressonância Magnética/métodos , Nervos Periféricos/diagnóstico por imagem , Nervo Tibial/diagnóstico por imagem , Estudos de Viabilidade , Humanos , Imageamento Tridimensional , Projetos Piloto
6.
J Nucl Med ; 59(6): 967-972, 2018 06.
Artigo em Inglês | MEDLINE | ID: mdl-29097408

RESUMO

Chronic sciatica is a major cause of disability worldwide, but accurate diagnosis of the causative pathology remains challenging. In this report, the feasibility of an 18F-FDG PET/MRI approach for improved diagnosis of chronic sciatica is presented. Methods:18F-FDG PET/MRI was performed on 9 chronic sciatica patients and 5 healthy volunteers (healthy controls). Region-of-interest analysis using SUVmax was performed, and 18F-FDG uptake in lesions was compared with that in the corresponding areas in healthy controls. Results: Significantly increased 18F-FDG uptake was observed in detected lesions in all patients and was correlated with pain symptoms. 18F-FDG-avid lesions not only were found in impinged spinal nerves but also were associated with nonspinal causes of pain, such as facet joint degeneration, pars defect, or presumed scar neuroma. Conclusion: The feasibility of 18F-FDG PET/MRI for diagnosing pain generators in chronic sciatica was demonstrated, revealing various possible etiologies.


Assuntos
Fluordesoxiglucose F18 , Imagem por Ressonância Magnética , Imagem Multimodal , Tomografia por Emissão de Pósitrons , Ciática/diagnóstico por imagem , Coluna Vertebral/diagnóstico por imagem , Adulto , Doença Crônica , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Dor/complicações , Ciática/complicações , Adulto Jovem
7.
Magn Reson Med ; 79(2): 968-973, 2018 02.
Artigo em Inglês | MEDLINE | ID: mdl-28444805

RESUMO

PURPOSE: To develop a fast 2D method for MRI near metal with reduced B0 in-plane and through-slice artifacts. METHODS: Multi-spectral imaging (MSI) approaches reduce artifacts in MR images near metal, but require 3D imaging of multiple excited volumes regardless of imaging geometry or artifact severity. The proposed 2D MSI method rapidly excites a limited slice and spectral region using gradient reversal between excitation and refocusing pulses, then uses standard 2D imaging, with the process repeating to cover multiple spectral offsets that are combined as in other MSI techniques. 2D MSI was implemented in a spin-echo-train sequence and validated in phantoms and in vivo by comparing it with standard spin-echo imaging and existing MSI techniques. RESULTS: 2D MSI images for each spatial-spectral region follow isocontours of the dipole-like B0 field variation, and thus frequency variation, near metal devices. Artifact correction in phantoms and human subjects with metal is comparable to 3D MSI methods, and superior to standard spin-echo techniques. Scan times are reduced compared with 3D MSI methods in cases where a limited number of slices are needed, though signal-to-noise ratio is also reduced as expected. CONCLUSION: 2D MSI offers a fast and flexible alternative to 3D MSI for artifact reduction near metal. Magn Reson Med 79:968-973, 2018. © 2017 International Society for Magnetic Resonance in Medicine.


Assuntos
Processamento de Imagem Assistida por Computador/métodos , Imagem por Ressonância Magnética/métodos , Metais/química , Artefatos , Parafusos Ósseos , Humanos , Joelho/diagnóstico por imagem , Imagens de Fantasmas
8.
J Nucl Med ; 58(12): 2004-2009, 2017 12.
Artigo em Inglês | MEDLINE | ID: mdl-28572487

RESUMO

The purpose of this study was to assess safety, biodistribution, and radiation dosimetry in humans for the highly selective σ-1 receptor PET agent 18F-6-(3-fluoropropyl)-3-(2-(azepan-1-yl)ethyl)benzo[d]thiazol-2(3H)-one (18F-FTC-146). Methods: Ten healthy volunteers (5 women, 5 men; age ± SD, 34.3 ± 6.5 y) were recruited, and written informed consent was obtained from all participants. Series of whole-body PET/MRI examinations were acquired for up to 3 h after injection (357.2 ± 48.8 MBq). Blood samples were collected, and standard vital signs (heart rate, pulse oximetry, and body temperature) were monitored at regular intervals. Regions of interest were delineated, time-activity curves were calculated, and organ uptake and dosimetry were estimated. Results: All subjects tolerated the PET/MRI examination well, and no adverse reactions to 18F-FTC-146 were reported. High accumulation of 18F-FTC-146 was observed in σ-1 receptor-dense organs such as the pancreas and spleen, moderate uptake in the brain and myocardium, and low uptake in bone and muscle. High uptake was also observed in the kidneys and bladder, indicating renal tracer clearance. The effective dose of 18F-FTC-146 was 0.0259 ± 0.0034 mSv/MBq (range, 0.0215-0.0301 mSv/MBq). Conclusion: First-in-human studies with clinical-grade 18F-FTC-146 were successful. Injection of 18F-FTC-146 is safe, and absorbed doses are acceptable. The potential of 18F-FTC-146 as an imaging agent for a variety of neuroinflammatory diseases is currently under investigation.


Assuntos
Azepinas/farmacocinética , Benzotiazóis/farmacocinética , Compostos Radiofarmacêuticos/farmacocinética , Adulto , Azepinas/efeitos adversos , Azepinas/síntese química , Benzotiazóis/efeitos adversos , Benzotiazóis/síntese química , Feminino , Voluntários Saudáveis , Humanos , Marcação por Isótopo , Imagem por Ressonância Magnética , Masculino , Imagem Multimodal , Radiometria , Compostos Radiofarmacêuticos/efeitos adversos , Compostos Radiofarmacêuticos/síntese química , Receptores sigma/efeitos dos fármacos , Receptores sigma/metabolismo , Distribuição Tecidual , Imagem Corporal Total
9.
Mol Imaging Biol ; 19(5): 779-786, 2017 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-28280965

RESUMO

PURPOSE: Sigma-1 receptors (S1Rs) play an important role in many neurological disorders. Simultaneous positron emission tomography (PET)/magnetic resonance imaging (MRI) with S1R radioligands may provide valuable information for diagnosing and guiding treatment for these diseases. Our previously reported S1R radioligand, [18F]FTC-146, demonstrated high affinity for the S1R (K i = 0.0025 nM) and excellent selectivity for the S1R over the sigma-2 receptor (S2Rs; K i = 364 nM) across several species (from mouse to non-human primate). Herein, we report the clinical-grade radiochemistry filed with exploratory Investigational New Drug (eIND) and first-in-human PET/MRI evaluation of [18F]FTC-146. PROCEDURES: [18F]FTC-146 is prepared via a direct [18F] fluoride nucleophilic radiolabeling reaction and formulated in 0.9 % NaCl containing no more than 10 % ethanol through sterile filtration. Quality control (QC) was performed based on USP 823 before doses were released for clinical use. The safety and whole body biodistribution of [18F]FTC-146 were evaluated using a simultaneous PET/MR scanner in two representative healthy human subjects. RESULTS: [18F]FTC-146 was synthesized with a radiochemical yield of 3.3 ± 0.7 % and specific radioactivity of 8.3 ± 3.3 Ci/µmol (n = 10, decay corrected to EOB). Both radiochemical and chemical purities were >95 %; the prepared doses were stable for 4 h at ambient temperature. All QC test results met specified clinical criteria. The in vivo PET/MRI investigations showed that [18F]FTC-146 rapidly crossed the blood brain barrier and accumulated in S1R-rich regions of the brain. There were also radioactivity distributed in the peripheral organs, i.e., the lungs, spleen, pancreas, and thyroid. Furthermore, insignificant uptake of [18F]FTC-146 was observed in cortical bone and muscle. CONCLUSION: A reliable and automated radiosynthesis for providing routine clinical-grade [18F]FTC-146 for human studies was established in a modified GE TRACERlab FXFN. PET/MRI demonstrated the initial tracer biodistribution in humans, and clinical studies investigating different S1R-related diseases are in progress.


Assuntos
Azepinas/química , Azepinas/síntese química , Benzotiazóis/química , Benzotiazóis/síntese química , Imagem por Ressonância Magnética , Tomografia por Emissão de Pósitrons , Adulto , Azepinas/farmacocinética , Benzotiazóis/farmacocinética , Feminino , Humanos , Masculino , Distribuição Tecidual
10.
Magn Reson Med ; 77(6): 2402-2413, 2017 06.
Artigo em Inglês | MEDLINE | ID: mdl-27385493

RESUMO

PURPOSE: To estimate the susceptibility and the geometry of metallic implants from multispectral imaging (MSI) information, to separate the metal implant region from the surrounding signal loss region. THEORY AND METHODS: The susceptibility map of signal-void regions is estimated from MSI B0 field maps using total variation (TV) regularized inversion. Voxels with susceptibility estimates above a predetermined threshold are identified as metal. The accuracy of the estimated susceptibility and implant geometry was evaluated in simulations, phantom, and in vivo experiments. RESULTS: The proposed method provided more accurate susceptibility estimation compared with a previous method without TV regularization, in both simulations and phantom experiments. In the phantom experiment where the actual implant was 40% of the signal-void region, the mean estimated susceptibility was close to the susceptibility in literature, and the precision and recall of the estimated geometry was 85% and 93%. In vivo studies in subjects with hip implants also demonstrated that the proposed method can distinguish implants from surrounding low-signal tissues, such as cortical bone. CONCLUSION: The proposed method can improve the delineation of metallic implant geometry by distinguishing metal voxels from artificial signal voids and low-signal tissues by estimating the susceptibility maps. Magn Reson Med 77:2402-2413, 2017. © 2016 International Society for Magnetic Resonance in Medicine.


Assuntos
Algoritmos , Interpretação de Imagem Assistida por Computador/métodos , Imageamento Tridimensional/métodos , Imagem por Ressonância Magnética/métodos , Metais , Próteses e Implantes , Humanos , Aumento da Imagem/métodos , Reprodutibilidade dos Testes , Sensibilidade e Especificidade
11.
Magn Reson Med ; 77(3): 1162-1169, 2017 03.
Artigo em Inglês | MEDLINE | ID: mdl-26991803

RESUMO

PURPOSE: The lack of a technique for MR thermometry near metal excludes a growing patient population from promising treatments such as MR-guided focused ultrasound therapy. Here we explore the feasibility of multispectral imaging (MSI) for noninvasive temperature measurement in the presence of strong field inhomogeneities by exploiting the temperature dependency of the T1 relaxation time. METHODS: A two-dimensional inversion-recovery-prepared MSI pulse sequence (2DMSI) was implemented for artifact-reduced T1 mapping near metal. A series of T1 maps was acquired in a metallic implant phantom while increasing the phantom temperature. The measured change in T1 was analyzed with respect to the phantom temperature. For comparison, proton resonance frequency shift (PRFS) thermometry was performed. RESULTS: 2DMSI achieved artifact-reduced, single-slice T1 mapping in the presence of strong off-resonance with a spatial resolution of 1.9 mm in-plane and a temporal resolution of 5 min. The maps enabled temperature measurements over a range of 30°C with an uncertainty below 1.4°C. The quality of the resulting temperature maps was independent of the distance from the metal, whereas the PRFS-based temperature measurements were increasingly impaired with increasing off-resonance. CONCLUSION: We demonstrated the ability to noninvasively measure temperature near metal using MSI and the T1 temperature sensitivity. Magn Reson Med 77:1162-1169, 2017. © 2016 International Society for Magnetic Resonance in Medicine.


Assuntos
Algoritmos , Artefatos , Interpretação de Imagem Assistida por Computador/métodos , Imagem por Ressonância Magnética/métodos , Metais , Processamento de Sinais Assistido por Computador , Termografia/métodos , Imagens de Fantasmas , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Temperatura
12.
J Neurosci Methods ; 268: 78-86, 2016 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-27172845

RESUMO

BACKGROUND: Recording EEG and fMRI data simultaneously inside a fully-operating scanner has been recognized as a novel approach in human brain research. Studies have demonstrated high concordance between the EEG signals and hemodynamic response. However, a few studies reported altered cognitive process inside the fMRI scanner such as delayed reaction time (RT) and reduced and/or delayed N100 and P300 event-related brain potential (ERP) components. NEW METHOD: The present study investigated the influence of electromagnetic field (static magnetic field, radio frequency (RF) pulse, and gradient switching) and experimental environment on posterior N100 and P300 ERP components in four different settings with six healthy subjects using a visual oddball task: (1) classic fMRI acquisition inside the scanner (e.g., supine position, mirror glasses for stimulus presentation), (2) standard behavioral experiment outside the scanner (e.g., seated position, keyboard response), (3) controlled fMRI acquisition inside the scanner (e.g., organic light-emitting diode (OLED) goggles for stimulus presentation) inside; and (4) modified behavioral experiment outside the scanner (e.g., supine position, OLED goggles). RESULTS: The study findings indicated that the experimental environment in simultaneous EEG/fMRI acquisition could substantially delay N1P, P300 latency, and RT inside the scanner, and was associated with a reduced N1P amplitude. COMPARISON WITH EXISTING METHODS: There was no effect of electromagnetic field in the prolongation of RT, N1P and P300 latency inside the scanner. N1P, but not P300, latency was sensitive to stimulus presentation method inside the scanner. CONCLUSION: Future simultaneous EEG/fMRI data collection should consider experimental environment in both design and analysis.


Assuntos
Encéfalo/fisiologia , Eletroencefalografia , Potenciais Evocados/fisiologia , Imagem por Ressonância Magnética , Imagem Multimodal , Tempo de Reação/fisiologia , Encéfalo/diagnóstico por imagem , Eletroencefalografia/métodos , Campos Eletromagnéticos , Feminino , Dedos/fisiologia , Humanos , Imagem por Ressonância Magnética/métodos , Masculino , Atividade Motora/fisiologia , Imagem Multimodal/métodos , Testes Neuropsicológicos , Fatores de Tempo , Percepção Visual/fisiologia
13.
Psychiatry Res ; 226(2-3): 484-8, 2015 Apr 30.
Artigo em Inglês | MEDLINE | ID: mdl-25747680

RESUMO

Dysfunction of the autonomic nervous system has been considered to be a risk factor for major depressive disorder (MDD) and cardiovascular disease (CVD). The aim of this study was to evaluate short-term heart rate variability (HRV) in elderly patients with newly diagnosed MDD. Thirty MDD patients over 60 years old newly diagnosed by a structured interview were enrolled, free from antidepressants. Socio-demographic data, blood tests, and heart rate variability (HRV) obtained from 5-min ECG were gathered. The MDD group showed significantly lower very low frequency power, low frequency power, high frequency power, and total power in frequency domain. In time domain analysis, the MDD group showed a significantly smaller standard deviation of the NN, root mean square of the differences of the successive NN, and NN50/total number of all NNs. These findings demonstrated a lower HRV in older patients who were newly diagnosed with depression without a history of CVD and antidepressants effect, compared with the control subjects. Low HRV may be an important predictor of both MDD and CVD in elderly. The use of HRV in elderly depressive patients could be a meaningful screening method for risk of CVD.


Assuntos
Doenças Cardiovasculares/diagnóstico , Doenças Cardiovasculares/fisiopatologia , Transtorno Depressivo Maior/diagnóstico , Transtorno Depressivo Maior/fisiopatologia , Frequência Cardíaca/fisiologia , Idoso , Idoso de 80 Anos ou mais , Sistema Nervoso Autônomo/fisiopatologia , Doenças Cardiovasculares/psicologia , Transtorno Depressivo Maior/psicologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Fatores de Risco
14.
Br J Clin Pharmacol ; 78(4): 727-37, 2014 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-24646010

RESUMO

AIMS: Our goal was to evaluate the association between antidepressant use and the risk of coronary heart disease (CHD) among subjects with no history of coronary heart disease. METHODS: A search of Medline, EMBASE, PsycINFO and the Cochrane Library was performed in January 2013. Two authors independently reviewed and selected eligible observational studies, based on predetermined selection criteria. Pooled relative risks (RRs) with confidence intervals (CIs) were calculated using random-effects or fixed-effects models. RESULTS: Sixteen observational studies (seven case-control studies and nine cohort studies) were included in the final analysis. There was no association between selective serotonin reuptake inhibitor use and the risk of CHD overall [odds ratio (OR), 0.93; 95% CI, 0.65-1.33] or in subgroup meta-analysis of case-control studies (OR, 0.91; 95% CI, 0.60-1.37) and cohort studies (RR, 0.96; 95% CI, 0.59-1.55). The use of tricyclic antidepressant was associated with an increased risk of CHD overall (OR, 1.51; 95% CI, 1.07-2.12), but it was observed only in case-control studies (OR, 1.56; 95% CI, 1.24-1.96) and low-quality studies (OR, 1.49; 95% CI, 1.20-1.85) in the subgroup meta-analyses. CONCLUSIONS: This meta-analysis of observational studies in subjects with no history of CHD suggests that neither selective serotonin reuptake inhibitor nor tricyclic antidepressant use is associated with an increased risk of CHD.


Assuntos
Antidepressivos/efeitos adversos , Doença das Coronárias/induzido quimicamente , Antidepressivos Tricíclicos/efeitos adversos , Feminino , Humanos , Masculino , Risco , Inibidores de Captação de Serotonina/efeitos adversos
15.
Asian Spine J ; 8(6): 729-34, 2014 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-25558314

RESUMO

STUDY DESIGN: Retrospective study. PURPOSE: To determine the prevalence of high risk patient with osteopenia requiring pharmacologic treatment and investigate the difference of 10-year fracture probability whether bone mineral density (BMD) include or not in Korean FRAX model. OVERVIEW OF LITERATURE: Many people with the fracture have osteopenia rather than osteoporosis, and BMD alone could be considered as a chance to prevent fracture. METHODS: Three hundred sixty-nine patients who was diagnosed as osteopenia were divided into two groups according to age (group 1, under 65 years; group 2, over 65 years), and 10-year fracture probabilities were calculated by FRAX algorithm with and without femur neck T-score. RESULTS: The high risk patients of the fracture who had above 3% of 10-year hip fracture probability were 15 cases in group 1 and 121 cases in group 2. In 193 patients of group 1, the mean 10-year fracture probability with BMD was significantly higher than the results without BMD (hip fracture: p=0.04, major osteoporotic fracture: p=0.01). Unlike the results of the group 1, the mean 10-year fracture probability without BMD was significantly higher than the results with BMD in 176 patients of group 2 (hip fracture: p=0.01, major osteoporotic fracture: p=0.01). CONCLUSIONS: Total of 136 cases (36.8%) as a high risk of the fracture with osteopenia could be overlooked treatment eligibility in Korean. The Korean FRAX model without BMD could be effective in predicting fracture risk especially in the individuals who were over 65 years.

16.
Magn Reson Med ; 69(3): 657-66, 2013 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-22511367

RESUMO

Small-tip fast recovery (STFR) imaging is a new steady-state imaging sequence that is a potential alternative to balanced steady-state free precession. Under ideal imaging conditions, STFR may provide comparable signal-to-noise ratio and image contrast as balanced steady-state free precession, but without signal variations due to resonance offset. STFR relies on a tailored "tip-up," or "fast recovery," radiofrequency pulse to align the spins with the longitudinal axis after each data readout segment. The design of the tip-up pulse is based on the acquisition of a separate off-resonance (B0) map. Unfortunately, the design of fast (a few ms) slice- or slab-selective radiofrequency pulses that accurately tailor the excitation pattern to the local B0 inhomogeneity over the entire imaging volume remains a challenging and unsolved problem. We introduce a novel implementation of STFR imaging based on "non-slice-selective" tip-up pulses, which simplifies the radiofrequency pulse design problem significantly. Out-of-slice magnetization pathways are suppressed using radiofrequency-spoiling. Brain images obtained with this technique show excellent gray/white matter contrast, and point to the possibility of rapid steady-state T(2)/T(1) -weighted imaging with intrinsic suppression of cerebrospinal fluid, through-plane vessel signal, and off-resonance artifacts. In the future, we expect STFR imaging to benefit significantly from parallel excitation hardware and high-order gradient shim systems.


Assuntos
Algoritmos , Encéfalo/anatomia & histologia , Aumento da Imagem/métodos , Interpretação de Imagem Assistida por Computador/métodos , Imagem por Ressonância Magnética/métodos , Processamento de Sinais Assistido por Computador , Humanos , Ondas de Rádio , Reprodutibilidade dos Testes , Sensibilidade e Especificidade
17.
Magn Reson Med ; 68(1): 278-85, 2012 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-22555857

RESUMO

A fast parallel excitation pulse design algorithm to select and to order phase-encoding (PE) locations (also known as "spokes") of an Echo-Volumar excitation k-space trajectory considering B(0) field inhomogeneity is presented. Recently, other groups have conducted research to choose optimal PE locations, but the potential benefit of considering B(0) field inhomogeneity during PE location selection or their ordering has not been fully investigated. This article introduces a novel fast greedy algorithm to determine PE locations and their order that takes into account the off-resonance effects. Computer simulations of the proposed algorithm for B(1) field inhomogeneity correction demonstrate that it not only improves excitation accuracy but also provides an effective ordering of the PE locations.


Assuntos
Algoritmos , Aumento da Imagem/métodos , Interpretação de Imagem Assistida por Computador/métodos , Imagem por Ressonância Magnética/métodos , Processamento de Sinais Assistido por Computador , Simulação por Computador , Análise Numérica Assistida por Computador , Imagens de Fantasmas , Ondas de Rádio , Reprodutibilidade dos Testes , Sensibilidade e Especificidade
18.
Chem Commun (Camb) ; 48(21): 2725-7, 2012 Mar 11.
Artigo em Inglês | MEDLINE | ID: mdl-22306978

RESUMO

Poly (3,4-(2-methylene)propylenedioxythiophene) (PMProDot) nanotubes were synthesized within the pores of polycarbonate and were further modified with styrene and vinylcarbazole by a one step electrochemical method through the methylene functional group. The enhanced electrochemical and electrochromic properties of composite nanotubes were investigated using FTIR, UV/Vis absorbance spectroscopy, and AFM.


Assuntos
Compostos Bicíclicos Heterocíclicos com Pontes/síntese química , Técnicas Eletroquímicas , Nanotubos/química , Tiofenos/síntese química , Compostos Bicíclicos Heterocíclicos com Pontes/química , Carbazóis/química , Nanotubos/ultraestrutura , Técnicas de Microbalança de Cristal de Quartzo , Estireno/química , Tiofenos/química
19.
Clin Orthop Surg ; 3(4): 268-73, 2011 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-22162788

RESUMO

BACKGROUND: To evaluate the effectiveness of minimally invasive surgery total hip arthroplasty (THA) using the two-incision technique as described by Mears. METHODS: From January 2003 to December 2006, sixty-four patients underwent total hip arthroplasty using the one-incision (group I) and two-incision (group II) technique by one surgeon. There were 34 hips in group I and 30 hips in group II. There was no difference in age, gender, and causes of THA between the two groups. We evaluated the operation time, bleeding amount, incision length, ambulation, hospital stay, and complications between the two groups. RESULTS: There was no difference in the bleeding amount between the two groups. Operation time was longer in the two-incision group than in the one-incision group. Operation time of the two-incision technique could be reduced after 15 cases. Patients started ambulation after surgery earlier in group II than group I, and the hospital stay was shorter in group II than in group I. There was no difference in clinical results between the two groups. There was no difference in component position of the acetabular cup and femoral stem between the two groups. Intraoperative periprosthetic fracture occurred in four cases (13.3%) in group II. CONCLUSIONS: Two-incision THA has the advantage of rapid recovery and shorter hospital stay. However, longer operation time and a high complication rate compared to one-incision are problems that need to be solved in the two-incision technique.


Assuntos
Artroplastia de Quadril/métodos , Procedimentos Cirúrgicos Minimamente Invasivos/métodos , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos
20.
J Orthop Sci ; 16(1): 21-5, 2011 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-21249404

RESUMO

PURPOSE: To evaluate the causes and frequency of the squeaking sound in ceramic-on-ceramic THA. MATERIALS AND METHODS: This study included 61 hips of 50 patients who underwent ceramic-on-ceramic THA in our hospital from March 1999 to April 2005. The average age at the time of operation was 57.6 years. The average duration of follow-up was 69.5 months. Three different acetabular components were used: Osteonics (Stryker, USA: 24 cases), Bicontact (Aesculap, Germany: 27 cases) and ABG (Howmedica, UK: 10 cases). RESULTS: Fourteen (22.9%) of the 61 cases had a squeaking sound, and this sound started a mean of 47.57 months after the operation. Except in one case, the squeaking sound remained until the last follow-up. There was no difference in acetabular component position between the squeaking and nonsqueaking groups. The squeaking sound was found to be related to the BMI (body mass index) and cup design. It occurred frequently in patients with high BMI who had received a total hip arthroplasty using an Osteonics cup. Among 11 of the patients, squeaking occurred while squatting, and in 3 patients while walking. Six patients suffered from mild restrictions on their activities of daily living, and 8 had more than moderate restrictions with squeaking sounds. CONCLUSION: A squeaking sound in THA using ceramic-on-ceramic surfaces is not a rare complication, and often affects the patient's behavior.


Assuntos
Artroplastia de Quadril/instrumentação , Cerâmica , Prótese de Quadril , Osteoartrite do Quadril/cirurgia , Amplitude de Movimento Articular/fisiologia , Adulto , Idoso , Análise de Falha de Equipamento , Feminino , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Osteoartrite do Quadril/fisiopatologia , Desenho de Prótese , Falha de Prótese , Estudos Retrospectivos , Propriedades de Superfície , Adulto Jovem
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