RESUMO
BACKGROUND: Intranasal (i.n.) drug application is a widely known and low-invasive route of administration that may be able to achieve rapid symptom control in terminally ill patients. According to the German S3 guideline "Palliative care for patients with incurable cancer", benzodiazepines, such as midazolam, are recommended for the treatment of terminal agitation. To the best of our knowledge there is no evidence for i.n. midazolam in terminally ill patients. We aim to assess the use of i.n. midazolam as an alternative to subcutaneous administration of the drug. METHODS: In this monocentric, randomised, controlled, open-label investigator initiated trial, n = 60 patients treated at the palliative care unit of a University Hospital will be treated with 5 mg midazolam i.n. versus 5 mg subcutaneous (s.c.) midazolam in the control arm when terminal agitation occurs (randomly assigned 1:1). The estimated recruitment period is 18 months. Treatment efficacy is defined as an improvement on the Richmond Agitation Sedation Scale (Palliative Version) (RASS-PAL) and a study specific numeric rating scale (NRS) before and after drug administration. Furthermore, plasma concentration determinations of midazolam will be conducted at t1 = 0 min, t2 = 5 min, and t3 = 20 min using liquid chromatography/mass spectrometry (LC-MS). The primary objective is to demonstrate non-inferiority of midazolam i.n. in comparison to midazolam s.c. for the treatment of agitation in terminally ill patients. DISCUSSION: Midazolam i.n. is expected to achieve at least equivalent reduction of terminal agitation compared to s.c. administration. In addition, plasma concentrations of midazolam i.n. are not expected to be lower than those of midazolam s.c. and the dynamics of the plasma concentration with an earlier increase could be beneficial. TRIAL REGISTRATION: German Clinical Trials Registry DRKS00026775, registered 07.07.2022, Eudra CT No.: 2021-004789-36.
Assuntos
Midazolam , Doente Terminal , Humanos , Midazolam/uso terapêutico , Cuidados Paliativos , Resultado do Tratamento , Ansiedade , Hipnóticos e Sedativos/uso terapêutico , Ensaios Clínicos Controlados Aleatórios como AssuntoRESUMO
Abuse of heroin vapour inhalation known as "chasing the dragon" is associated with toxic spongiform leukoencephalopathy. However, similar clinical and imaging findings may occur also after intravenous heroin abuse. We report on a 32-year-old male suffering from extensive toxic spongiform leukoencephalopathy after intravenous heroin abuse resulting in acute impairment of consciousness and a global state of confusion. MRI disclosed broad and nearly symmetrical diffusion restriction of the supratentorial white matter indicating cytotoxic oedema. In an emergency setting, differential diagnosis of acute impairment of consciousness and broad symmetrical white matter lesions in neuroimaging should also include toxic leukoencephalopathy due to intravenous heroin application.
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Dependência de Heroína , Leucoencefalopatias , Masculino , Humanos , Adulto , Heroína/toxicidade , Dependência de Heroína/complicações , Estado de Consciência , Diagnóstico Diferencial , Leucoencefalopatias/diagnóstico , Leucoencefalopatias/diagnóstico por imagem , Imageamento por Ressonância MagnéticaRESUMO
Cardiovascular magnetic resonance (CMR) phase contrast imaging has undergone a wide range of changes with the development and availability of improved calibration procedures, visualization tools, and analysis methods. This article provides a comprehensive review of the current state-of-the-art in CMR phase contrast imaging methodology, clinical applications including summaries of past clinical performance, and emerging research and clinical applications that utilize today's latest technology.
Assuntos
Doença da Artéria Coronariana/diagnóstico , Vasos Coronários/fisiopatologia , Doenças das Valvas Cardíacas/diagnóstico , Valvas Cardíacas/fisiopatologia , Imageamento por Ressonância Magnética , Imagem de Perfusão do Miocárdio/métodos , Artefatos , Velocidade do Fluxo Sanguíneo , Doença da Artéria Coronariana/patologia , Doença da Artéria Coronariana/fisiopatologia , Circulação Coronária , Vasos Coronários/patologia , Doenças das Valvas Cardíacas/patologia , Doenças das Valvas Cardíacas/fisiopatologia , Valvas Cardíacas/patologia , Humanos , Interpretação de Imagem Assistida por Computador , Modelos Cardiovasculares , Valor Preditivo dos Testes , Prognóstico , Reprodutibilidade dos Testes , Índice de Gravidade de Doença , Fatores de TempoRESUMO
PURPOSE: To compare the spatial accuracy of three typical active tracking sequences using a new, unique phantom design. MATERIALS AND METHODS: Three different tracking sequences (Single Echo, Dual Echo and Hadamard Multiplexed) were compared with each other in a phantom study with respect to their positional accuracy. A custom-built phantom was constructed to conduct the experiments with precise framework conditions which facilitated sufficient measurement accuracy. An electrophysiology catheter incorporating four micro-coils was used as an interventional device. Tracking profiles were acquired in all three spatial dimensions and validated against the distances that were measured by a Vernier caliper in combination with a three-dimensional reference scan. RESULTS: The Bland-Altman plots demonstrated that all three sequences show < 1.5 mm positional error. The measurement accuracy of Single Echo and Double Echo are prone to off-resonances, whereas Hadamard Encoding is immune to it. CONCLUSION: The developed phantom enabled the performance of objective measurements of the accuracy of different active tracking sequences. The proposed setup allows for objectively contrasting different methods for interventional procedures.
Assuntos
Algoritmos , Interpretação de Imagem Assistida por Computador/métodos , Imagem por Ressonância Magnética Intervencionista/instrumentação , Imagem por Ressonância Magnética Intervencionista/métodos , Imagens de Fantasmas , Desenho de Equipamento , Análise de Falha de Equipamento , Humanos , Aumento da Imagem/métodos , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Processamento de Sinais Assistido por ComputadorRESUMO
BACKGROUND: Coronary artery disease (CAD) confers increased risks of premature mortality, non-fatal morbidity, and significant impairment in functional status and health-related quality of life. Routine administration of electronic patient-reported outcome measures (PROMs) and its real time delivery to care providers is known to have the potential to inform routine cardiac care and to improve quality of care and patient outcomes. This study describes a user-centered development and evaluation of the Alberta Provincial Project for Outcomes Assessment (APPROACH) electronic Patient Reported Outcomes Measurement (e-PROM) system. This e-PROM system is an electronic system for the administration of PROMs to patients with CAD and the delivery of the summarized information to their care providers to facilitate patient-physician communication and shared decision-making. This electronic platform was designed to be accessible via web-based and hand-held devices. Heuristic and user acceptance evaluation were conducted with patients and attending care providers. RESULTS: The APPROACH e-PROM system was co-developed with patients and care providers, research investigators, informaticians and information technology experts. Five PROMs were selected for inclusion in the online platform after consultations with patient partners, care providers, and PROMs experts: the Seattle Angina Questionnaire, Patient Health Questionnaire, EuroQOL, and Medical Outcomes Study Social Support Survey, and Self-Care of Coronary Heart Disease Inventory. The heuristic evaluation was completed by four design experts who examined the usability of the prototype interfaces. User acceptance testing was completed with 13 patients and 10 cardiologists who evaluated prototype user interfaces of the e-PROM system. CONCLUSION: Both patients and physicians found the APPROACH e-PROM system to be easy to use, understandable, and acceptable. The APPROACH e-PROM system provides a user-informed electronic platform designed to incorporate PROMs into the delivery of individualized cardiac care for persons with CAD.
Assuntos
Doença da Artéria Coronariana , Medidas de Resultados Relatados pelo Paciente , Humanos , Doença da Artéria Coronariana/terapia , Feminino , Masculino , Alberta , Qualidade de Vida , Pessoa de Meia-Idade , Design Centrado no Usuário , Idoso , Internet , Relações Médico-PacienteRESUMO
PURPOSE: To develop and evaluate software-based methods for improving the workflow of magnetic resonance (MR)-guided percutaneous interventions. MATERIALS AND METHODS: A set of methods was developed that allows the user to: 1) plan an entire procedure, 2) directly apply this plan to skin entry site localization without further imaging, and 3) place a needle under real-time MR guidance with automatic alignment of three orthogonal slices along a planned trajectory with preference to the principal patient axes. To validate targeting accuracy and time, phantom experiments (96 targets) and in vivo paraspinal and kidney needle punctures in two pigs (55 targets) were performed. The influence of trajectory obliquity, level of experience, and organ motion on targeting accuracy and time was analyzed. RESULTS: Mean targeting error was 1.8 ± 0.9 mm (in vitro) and 2.9 ± 1.0 mm (in vivo) in all directions. No statistically significant differences in targeting accuracy between single- and double-oblique trajectories, novice and expert users, or paraspinal and kidney punctures were observed. The average time (in vivo) from trajectory planning to verification of accurate needle placement was 6 minutes. CONCLUSION: The developed methods allow for accurate needle placement along complex trajectories and are anticipated to reduce table time for MR-guided percutaneous needle interventions.
Assuntos
Técnicas de Ablação/métodos , Biópsia por Agulha/métodos , Interpretação de Imagem Assistida por Computador/métodos , Biópsia Guiada por Imagem/métodos , Injeções/métodos , Imagem por Ressonância Magnética Intervencionista/métodos , Fluxo de Trabalho , Técnicas de Ablação/instrumentação , Algoritmos , Animais , Biópsia por Agulha/instrumentação , Estudos de Viabilidade , Aumento da Imagem/métodos , Biópsia Guiada por Imagem/instrumentação , Imageamento Tridimensional/métodos , Injeções/instrumentação , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Software , SuínosRESUMO
OBJECTIVE: To compare the coefficient of variation (CV) and long-term reproducibility of apparent diffusion coefficient (ADC) in a simple fluid-filled phantom and abdominal organs simultaneously. MATERIALS AND METHODS: Retrospective institutional review board-approved and Health Insurance Portability and Accountability Act-compliant study sequentially selected 100 patients who underwent clinically indicated abdominal magnetic resonance imaging. A subset of 58 patients had repeat scans within 2 to 5 months after the initial magnetic resonance imaging. Two diffusion-weighted imaging techniques (b-values 0-750 mm/s) were performed to compare the ADC values. Mean ADC values were calculated for 10 locations and the reference phantom. The CV and Bland-Altman plots were calculated for the phantom and soft tissues at each session and location. RESULTS: There were no significant differences in the mean ADC values between repeated acquisitions. However, ADC values were statistically higher using dual-b-value than multi-b-value diffusion-weighted imaging. The CV for the phantom was 8.6 versus 10.8 for dual-b-value and multi-b-value, respectively. The CVs for the soft tissues had a wider range compared with that of the phantom (liver, 12.6 vs 9.0; spleen, 11.7 vs 11.2; gallbladder, 11.0 vs 13.6; head of pancreas, 14.6 vs 14.7; body of pancreas, 13.4 vs 13.0; tail of pancreas, 14.8 vs 16.3; right kidney, 9.1 vs 9.6; left kidney, 9.3 vs 9.3; right paraspinal muscle, 7.9 vs 7.5; left paraspinal muscle, 7.3 vs 7.3, respectively). CONCLUSIONS: A change in ADC less than 11% falls into the range of measurement variability. Paraspinal muscle could potentially be used as an internal reference parameter.
Assuntos
Abdome , Imagem de Difusão por Ressonância Magnética/métodos , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Imagens de Fantasmas , Reprodutibilidade dos Testes , Estudos RetrospectivosRESUMO
The purpose of this study is to develop and evaluate a displacement-encoded pulse sequence for simultaneous perfusion and strain imaging. Displacement-encoded images in two to three myocardial slices were repeatedly acquired using a single-shot pulse sequence for 3 to 4 min, which covers a bolus infusion of Gadolinium contrast. The magnitudes of the images were T(1) weighted and provided quantitative measures of perfusion, while the phase maps yielded strain measurements. In an acute coronary occlusion swine protocol (n = 9), segmental perfusion measurements were validated against microsphere reference standard with a linear regression (slope 0.986, R(2) = 0.765, Bland-Altman standard deviation = 0.15 mL/min/g). In a group of ST-elevation myocardial infarction patients (n = 11), the scan success rate was 76%. Short-term contrast washout rate and perfusion are highly correlated (R(2) = 0.72), and the pixelwise relationship between circumferential strain and perfusion was better described with a sigmoidal Hill curve than linear functions. This study demonstrates the feasibility of measuring strain and perfusion from a single set of images.
Assuntos
Circulação Coronária , Técnicas de Imagem por Elasticidade/métodos , Coração/fisiopatologia , Interpretação de Imagem Assistida por Computador/métodos , Armazenamento e Recuperação da Informação/métodos , Infarto do Miocárdio/fisiopatologia , Imagem de Perfusão do Miocárdio/métodos , Idoso , Idoso de 80 Anos ou mais , Algoritmos , Animais , Velocidade do Fluxo Sanguíneo , Humanos , Aumento da Imagem/métodos , Pessoa de Meia-Idade , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Processamento de Sinais Assistido por Computador , Técnica de Subtração , SuínosRESUMO
Cine MRI is used for assessing cardiac function and flow and is typically based on a breath-held, segmented data acquisition. Breath holding is particularly difficult for patients with congestive heart failure or in pediatric cases. Real-time imaging may be used without breath holding or ECG triggering. However, despite the use of rapid imaging sequences and accelerated parallel imaging, real-time imaging typically has compromised spatial and temporal resolution compared with gated, segmented breath-held studies. A new method is proposed that produces a cardiac cine across the full cycle, with both high spatial and temporal resolution from a retrospective reconstruction of data acquired over multiple heartbeats during free breathing. The proposed method was compared with conventional cine images in 10 subjects. The resultant image quality for the proposed method (4.2 +/- 0.4) without breath holding or gating was comparable to the conventional cine (4.4 +/- 0.5) on a five-point scale (P = n.s.). Motion-corrected averaging of real-time acquired cardiac images provides a means of attaining high-quality cine images with many of the benefits of real-time imaging, such as free-breathing acquisition and tolerance to arrhythmias.
Assuntos
Artefatos , Técnicas de Imagem de Sincronização Cardíaca/métodos , Doença da Artéria Coronariana/diagnóstico , Aumento da Imagem/métodos , Imagem Cinética por Ressonância Magnética/métodos , Infarto do Miocárdio/diagnóstico , Técnicas de Imagem de Sincronização Respiratória/métodos , Algoritmos , Sistemas Computacionais , Humanos , Interpretação de Imagem Assistida por Computador/métodos , Movimento (Física) , Reprodutibilidade dos Testes , Sensibilidade e EspecificidadeRESUMO
Black blood turbo spin echo (TSE) imaging of the right ventricle (RV) free wall is highly sensitive to cardiac motion, frequently resulting in nondiagnostic images. Temporal and spatial parameters of a black blood TSE pulse sequence were evaluated for visualization of the RV free wall. Seventy-four patient studies were retrospectively evaluated for the effects of acquisition timing on image quality. Axial black blood TSE images were acquired on 10 healthy volunteers to assess the role of spatial misregistration on right ventricle visualization; increasing the double inversion recovery (DIR) slice thickness beyond 300% had no effect on image quality (P = 0.2). Thirty-five patient studies were prospectively evaluated with inversion times (TIs) corresponding to the mid-diastolic rest period and end-systole based on visual analysis of a four chamber cine. When TIs were chosen to be within the patients' RV rest period, mean image quality score was significantly improved (2.3 vs 1.86; P < 0.001) and the number of clinically diagnostic images increased from 32% to 46%. Black blood TSE imaging of the RV free wall is highly sensitive to cardiac motion. Image quality can be improved by choosing TIs concordant with the rest period of the patient's RV that may occur at mid-diastole or end-systole.
Assuntos
Algoritmos , Imagem Ecoplanar/métodos , Ventrículos do Coração/patologia , Interpretação de Imagem Assistida por Computador/métodos , Disfunção Ventricular Direita/patologia , Adulto , Meios de Contraste , Feminino , Humanos , Aumento da Imagem/métodos , Masculino , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Marcadores de SpinRESUMO
A method to reduce the effect of motion variability in MRI of the coronary arteries is proposed. It involves acquiring real-time low-resolution images in specific orthogonal orientations, extracting coronary motion from these images, and then using this motion information to guide high-resolution MR image acquisition on a beat-to-beat basis. The present study establishes the feasibility and efficacy of the proposed approach using human motion data in an offline implementation, prior to future online implementation on an MRI scanner. To track the coronary arteries in low-resolution real-time MR images in an accurate manner, a tracking approach is presented and validated. The tracking algorithm was run on real-time images acquired at 15-20 frames per second in four-chamber, short-axis, and coronal views in five volunteers. The systolic and diastolic periods in the cardiac cycles, computed from the extracted motion information, had significant variability during the short time periods typical of cardiac MRI. It is also demonstrated through simulation analysis using human tracked coronary motion data that accounting for this cardiac variability by adaptively changing the trigger delay for acquisition on a beat-to-beat basis improves overall motion compensation and hence MR image quality evaluated in terms of SNR and CNR values.
Assuntos
Angiografia Coronária/métodos , Angiografia por Ressonância Magnética/métodos , Movimento/fisiologia , Adulto , Algoritmos , Angiografia Coronária/normas , Erros de Diagnóstico , Estudos de Viabilidade , Feminino , Humanos , Aumento da Imagem , Angiografia por Ressonância Magnética/normas , Masculino , Reprodutibilidade dos Testes , Adulto JovemRESUMO
Soon after the introduction of MR imaging as an imaging tool, researchers began to investigate its capabilities to guide interventional minimally invasive procedures, such as biopsies. These early efforts have encouraged vendors and numerous research groups worldwide to identify clinical problems in the field of image-guided intervention, for which MR imaging is beneficial as an imaging modality, and to develop and refine soft-ware and hardware components to meet the specific requirements of interventional MR imaging. Over nearly 20 years, continuous advances in magnet and system design have accelerated the progress of MR-guided intervention.
Assuntos
Imageamento por Ressonância Magnética/instrumentação , Procedimentos Cirúrgicos Operatórios , Desenho de Equipamento , Arquitetura de Instituições de Saúde , HumanosRESUMO
BACKGROUND: Despite highly active antiretroviral therapy (HAART), chronic involuntary weight loss still remains a serious problem in the care of HIV patients. Various alterations in energy metabolism and endocrine regulation have been found to cause loss of lean body mass (LBM) and body cell mass (BCM). Previous studies in HIV-positive men undergoing androgen replacement therapy or treatment with recombinant growth hormone (rGH) have shown partial restoration of LBM, but these treatments have largely been ineffective in eugonadal individuals. STUDY DESIGN: Double-blind, randomized, placebo-controlled trial of 89 HIV-positive women and men with wasting assigned to the anabolic steroid oxymetholone [50 mg twice (BID) or three times daily (TID)] or placebo for 16 weeks followed by open-label treatment. STUDY ENDPOINTS: Body weight, bioimpedance measurements, quality of life parameters and appetite. RESULTS: Oxymetholone led to a significant weight gain of 3.0 +/- 0.5 and 3.5 +/- 0.7 kg in the TID and BID groups, respectively (P < 0.05 for each treatment versus placebo), whereas individuals in the placebo group gained an average of 1.0 +/- 0.7 kg. Body cell mass increased in the oxymetholone BID group (3.8 +/- 0.4 kg; P < 0.0001) and in the oxymetholone TID group (2.1 +/- 0.6 kg; P < 0.005), corresponding to 12.4 and 7.4% of baseline BCM, respectively. Significant improvements were noted in appetite and food intake, increased well-being and reduced weakness by self-examination. The most important adverse event was liver-associated toxicity. Overall, 35% of patients in the TID, 27% of patients in the BID oxymetholone group and no patients in the placebo group had a greater than five times baseline increase for alanine aminotransferase during the double-blind phase of the study. CONCLUSIONS: Oxymetholone can be considered an effective anabolic steroid in eugonadal male and female patients with AIDS-associated wasting. The BID (100 mg/day) regimen appeared to be equally effective as the TID (150 mg/day) regimen in terms of weight gain, LBM and BCM and was associated with less, but still significant liver toxicity.
Assuntos
Anabolizantes/uso terapêutico , Síndrome de Emaciação por Infecção pelo HIV/tratamento farmacológico , Oximetolona/uso terapêutico , Adulto , Idoso , Anabolizantes/efeitos adversos , Apetite/efeitos dos fármacos , Composição Corporal/efeitos dos fármacos , Doença Hepática Induzida por Substâncias e Drogas , Método Duplo-Cego , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estado Nutricional , Oximetolona/efeitos adversos , Qualidade de Vida , Testosterona/sangue , Aumento de Peso/efeitos dos fármacosRESUMO
BACKGROUND: Despite highly active antiretroviral therapy (HAART), chronic involuntary weight loss still remains a serious problem in the care of HIV patients due to various alterations in energy metabolism and endocrine regulation. Previous studies in HIV-positive men undergoing androgen replacement therapy or treatment with recombinant growth hormone (rGH) have shown partial restoration of lean body mass (LBM), but these treatments have largely not been sufficiently studied in eugonadal individuals. METHOD: A double-blind, randomized, placebo-controlled trial of 89 HIV-positive eugonadal women and men with wasting assigned to the anabolic steroid oxymetholone (50 mg bid or tid) or placebo for 16 weeks was performed. Body weight, bioimpedance measurements, quality of life parameters, and appetite were analyzed. RESULTS: Oxymetholone led to a significant weight gain of 3.0 +/- 0.5 and 3.5 +/- 0.7 kg in the tid and bid groups, respectively (p <.05 for each treatment versus placebo), while individuals in the placebo group gained an average of 1.0 +/- 0.7 kg. Body cell mass (BCM) increased in the oxymetholone bid group (3.8 +/- 0.4 kg; p <.0001) and in the oxymetholone tid group (2.1 +/- 0.6 kg; p <.005). Significant improvements were noted in appetite and food intake, increased wellbeing, and reduced weakness by self-examination. The most important adverse event was liver-associated toxicity. Overall, 43% of patients in the tid group, 25% of patients in the bid oxymetholone group, and 8% in the placebo group had a greater than 5 times baseline increase for ALT, AST, or gamma GT, while other adverse events were not increased over placebo. CONCLUSION: Oxymetholone can be considered an effective anabolic steroid in eugonadal male and female patients with AIDS-associated wasting. The bid (100 mg/day) regimen appeared to be equally effective to the tid (150 mg/day) regimen in terms of weight gain, LBM, and BCM and was associated with less liver toxicity.
Assuntos
Infecções por HIV/complicações , Síndrome de Emaciação por Infecção pelo HIV/complicações , Síndrome de Emaciação por Infecção pelo HIV/tratamento farmacológico , Oximetolona/uso terapêutico , Adulto , Idoso , Apetite/efeitos dos fármacos , Composição Corporal/efeitos dos fármacos , Peso Corporal/efeitos dos fármacos , Método Duplo-Cego , Feminino , Síndrome de Emaciação por Infecção pelo HIV/sangue , Hormônios/sangue , Humanos , Masculino , Pessoa de Meia-Idade , Oximetolona/administração & dosagem , Oximetolona/efeitos adversos , Oximetolona/farmacologia , Qualidade de VidaRESUMO
Due to the high sensitivity of diffusion tensor imaging (DTI) to physiological motion, clinical DTI scans often suffer a significant amount of artifacts. Tensor-fitting-based, post-processing outlier rejection is often used to reduce the influence of motion artifacts. Although it is an effective approach, when there are multiple corrupted data, this method may no longer correctly identify and reject the corrupted data. In this paper, we introduce a new criterion called "corrected Inter-Slice Intensity Discontinuity" (cISID) to detect motion-induced artifacts. We compared the performance of algorithms using cISID and other existing methods with regard to artifact detection. The experimental results show that the integration of cISID into fitting-based methods significantly improves the retrospective detection performance at post-processing analysis. The performance of the cISID criterion, if used alone, was inferior to the fitting-based methods, but cISID could effectively identify severely corrupted images with a rapid calculation time. In the second part of this paper, an outlier rejection scheme was implemented on a scanner for real-time monitoring of image quality and reacquisition of the corrupted data. The real-time monitoring, based on cISID and followed by post-processing, fitting-based outlier rejection, could provide a robust environment for routine DTI studies.
Assuntos
Imagem de Tensor de Difusão/métodos , Imagem de Tensor de Difusão/normas , Interpretação de Imagem Assistida por Computador , Processamento de Imagem Assistida por Computador , Artefatos , Encéfalo/patologia , Humanos , Movimento (Física) , Curva ROC , Reprodutibilidade dos TestesRESUMO
In this paper we first discuss the technical challenges preventing an automated analysis of cardiac perfusion MR images and subsequently present a fully unsupervised workflow to address the problems. The proposed solution consists of key-frame detection, consecutive motion compensation, surface coil inhomogeneity correction using proton density images and robust generation of pixel-wise perfusion parameter maps. The entire processing chain has been implemented on clinical MR systems to achieve unsupervised inline analysis of perfusion MRI. Validation results are reported for 260 perfusion time series, demonstrating feasibility of the approach.
Assuntos
Algoritmos , Interpretação de Imagem Assistida por Computador/métodos , Angiografia por Ressonância Magnética/métodos , Imagem de Perfusão do Miocárdio/métodos , Reconhecimento Automatizado de Padrão/métodos , Humanos , Aumento da Imagem/métodos , Sistemas On-Line , Reprodutibilidade dos Testes , Sensibilidade e EspecificidadeRESUMO
Defining myocardial contours is often the most time-consuming portion of dynamic cardiac MRI image analysis. Displacement encoding with stimulated echoes (DENSE) is a quantitative MRI technique that encodes tissue displacement into the phase of the complex MRI images. Cine DENSE provides a time series of these images, thus facilitating the non-invasive study of myocardial kinematics. Epicardial and endocardial contours need to be defined at each frame on cine DENSE images for the quantification of regional displacement and strain as a function of time. This work presents a reliable and effective two-dimensional semi-automated segmentation technique that uses the encoded motion to project a manually-defined region of interest through time. Contours can then easily be extracted for each cardiac phase. This method boasts several advantages, including, (1) parameters are based on practical physiological limits, (2) contours are calculated for the first few cardiac phases, where it is difficult to visually distinguish blood from myocardium, and (3) the method is independent of the shape of the tissue delineated and can be applied to short- or long-axis views, and on arbitrary regions of interest. Motion-guided contours were compared to manual contours for six conventional and six slice-followed mid-ventricular short-axis cine DENSE datasets. Using an area measure of segmentation error, the accuracy of the segmentation algorithm was shown to be similar to inter-observer variability. In addition, a radial segmentation error metric was introduced for short-axis data. The average radial epicardial segmentation error was 0.36+/-0.08 and 0.40+/-0.10 pixels for slice-followed and conventional cine DENSE, respectively, and the average radial endocardial segmentation error was 0.46+/-0.12 and 0.46+/-0.16 pixels for slice following and conventional cine DENSE, respectively. Motion-guided segmentation employs the displacement-encoded phase shifts intrinsic to DENSE MRI to accurately propagate a single set of pre-defined contours throughout the remaining cardiac phases.
Assuntos
Algoritmos , Artefatos , Coração/anatomia & histologia , Aumento da Imagem/métodos , Interpretação de Imagem Assistida por Computador/métodos , Imagem Cinética por Ressonância Magnética/métodos , Reconhecimento Automatizado de Padrão/métodos , Técnica de Subtração , Análise por Conglomerados , Humanos , Movimento (Física) , Reprodutibilidade dos Testes , Sensibilidade e EspecificidadeRESUMO
PURPOSE: To compare standard of care nuclear SPECT imaging with cardiac magnetic resonance imaging (MRI) for emergency room (ER) patients with chest pain and intermediate probability for coronary artery disease. MATERIALS AND METHODS: Thirty-one patients with chest pain, negative electrocardiogram (ECG), and negative cardiac enzymes who underwent cardiac single photon emission tomography (SPECT) within 24 h of ER admission were enrolled. Patients underwent a comprehensive cardiac MRI exam including gated cine imaging, adenosine stress and rest perfusion imaging and delayed enhancement imaging. Patients were followed for 14 +/- 4.7 months. RESULTS: Of 27 patients, 8 (30%) showed subendocardial hypoperfusion on MRI that was not detected on SPECT. These patients had a higher rate of diabetes (P = 0.01) and hypertension (P = 0.01) and a lower global myocardial perfusion reserve (P = 0.01) compared with patients with a normal cardiac MRI (n = 10). Patients with subendocardial hypoperfusion had more risk factors for cardiovascular disease (mean 4.4) compared with patients with a normal MRI (mean 2.5; P = 0.005). During the follow-up period, patients with subendocardial hypoperfusion on stress MRI were more likely to return to the ER with chest pain compared with patients who had a normal cardiac MRI (P = 0.02). Four patients did not finish the MR exam due to claustrophobia. CONCLUSION: In patients with chest pain, diabetes and hypertension, cardiac stress perfusion MRI identified diffuse subendocardial hypoperfusion defects in the ER setting not seen on cardiac SPECT, which is suspected to reflect microvascular disease.
Assuntos
Adenosina , Dor no Peito/etiologia , Teste de Esforço/métodos , Imagem Cinética por Ressonância Magnética/métodos , Tomografia Computadorizada de Emissão de Fóton Único , Vasodilatadores , Dor no Peito/diagnóstico , Dor no Peito/diagnóstico por imagem , Angiografia Coronária , Circulação Coronária , Eletrocardiografia , Serviço Hospitalar de Emergência , Feminino , Humanos , Masculino , Microcirculação , Pessoa de Meia-Idade , Estudos Prospectivos , Fatores de Risco , Estatísticas não ParamétricasRESUMO
With the recent advances in magnetic resonance (MR) labeling of cellular therapeutics, it is natural that interventional MRI techniques for targeting would be developed. This review provides an overview of the current methods of stem cell labeling and the challenges that are created with respect to interventional MRI administration. In particular, stem cell therapies will require specialized, MR-compatible devices as well as integration of graphical user interfaces with pulse sequences designed for interactive, real-time delivery in many organs. Specific applications that are being developed will be reviewed as well as strategies for future translation to the clinical realm.