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1.
Cancers (Basel) ; 15(13)2023 Jun 21.
Artigo em Inglês | MEDLINE | ID: mdl-37444384

RESUMO

PURPOSE: The Response Assessment in Neuro-Oncology (RANO) criteria for lower-grade gliomas (LGGs) define tumor progression as ≥25% change in the T2/FLAIR signal area based on an operator's discretion of the perpendicular diameter of the largest tumor cross-section. Potential sources of error include acquisition inconsistency of 2D slices, operator selection variabilities in both representative tumor cross-section and measurement line locations, and the inability to quantify infiltrative tumor margins and satellite lesions. Our goal was to assess the accuracy and reproducibility of RANO in LG. MATERIALS AND METHODS: A total of 651 FLAIR MRIs from 63 participants with LGGs were retrospectively analyzed by three blinded attending physicians and three blinded resident trainees using RANO criteria, 2D visual assessment, and computer-assisted 3D volumetric assessment. RESULTS: RANO product measurements had poor-to-moderate inter-operator reproducibility (r2 = 0.28-0.82; coefficient of variance (CV) = 44-110%; mean percent difference (diff) = 0.4-46.8%) and moderate-to-excellent intra-operator reproducibility (r2 = 0.71-0.88; CV = 31-58%; diff = 0.3-23.9%). When compared to 2D visual ground truth, the accuracy of RANO compared to previous and baseline scans was 66.7% and 65.1%, with an area under the ROC curve (AUC) of 0.67 and 0.66, respectively. When comparing to volumetric ground truth, the accuracy of RANO compared to previous and baseline scans was 21.0% and 56.5%, with an AUC of 0.39 and 0.55, respectively. The median time delay at diagnosis was greater for false negative cases than for false positive cases for the RANO assessment compared to previous (2.05 > 0.50 years, p = 0.003) and baseline scans (1.08 > 0.50 years, p = 0.02). CONCLUSION: RANO-based assessment of LGGs has moderate reproducibility and poor accuracy when compared to either visual or volumetric ground truths.

2.
Pain ; 164(10): 2285-2295, 2023 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-37326674

RESUMO

ABSTRACT: This observational study aimed to determine whether individuals with fibromyalgia (FM) exhibit higher levels of neuroinflammation than healthy controls (HCs), as measured with positron emission tomography using [ 18 F]DPA-714, a second-generation radioligand for the translocator protein (TSPO). Fifteen women with FM and 10 HCs underwent neuroimaging. Distribution volume (V T ) was calculated for in 28 regions of interest (ROIs) using Logan graphical analysis and compared between groups using multiple linear regressions. Group (FM vs HC) was the main predictor of interest and TSPO binding status (high- vs mixed-affinity) was added as a covariate. The FM group had higher V T in the right postcentral gyrus ( b = 0.477, P = 0.033), right occipital gray matter (GM; b = 0.438, P = 0.039), and the right temporal GM ( b = 0.466, P = 0.042). The FM group also had lower V T than HCs in the left isthmus of the cingulate gyrus ( b = -0.553, P = 0.014). In the subgroup of high-affinity binders, the FM group had higher V T in the bilateral precuneus, postcentral gyrus, parietal GM, occipital GM, and supramarginal gyrus. Group differences in the right parietal GM were associated with decreased quality of life, higher pain severity and interference, and cognitive problems. In support of our hypothesis, we found increased radioligand binding (V T ) in the FM group compared with HCs in several brain regions regardless of participants' TSPO binding status. The ROIs overlapped with prior reports of increased TSPO binding in FM. Overall, increasing evidence supports the hypothesis that FM involves microglia-mediated neuroinflammation in the brain.


Assuntos
Fibromialgia , Humanos , Feminino , Fibromialgia/complicações , Fibromialgia/diagnóstico por imagem , Fibromialgia/metabolismo , Doenças Neuroinflamatórias , Qualidade de Vida , Tomografia por Emissão de Pósitrons/métodos , Encéfalo/diagnóstico por imagem , Encéfalo/metabolismo , Receptores de GABA/metabolismo
3.
J Nucl Med ; 63(2): 287-293, 2022 02.
Artigo em Inglês | MEDLINE | ID: mdl-34049986

RESUMO

Measuring amyloid and predicting tau status using a single amyloid PET study would be valuable for assessing brain AD pathophysiology. We hypothesized that early-frame amyloid PET (efAP) correlates with the presence of tau pathology because the initial regional brain concentrations of radioactivity are determined primarily by blood flow, which is expected to be decreased in the setting of tau pathology. Methods: The study included 120 participants (63 amyloid-positive and 57 amyloid-negative) with dynamic 18F-florbetapir PET and static 18F-flortaucipir PET scans obtained within 6 mo of each other. These subjects were predominantly cognitively intact in both the amyloid-positive (63%) and the amyloid-negative (93%) groups. Parameters for efAP quantification were optimized for stratification of tau PET positivity, assessed by either a tauopathy score or Braak regions. The ability of efAP to stratify tau positivity was measured using receiver-operating-characteristic analysis of area under the curve (AUC). Pearson r and Spearman ρ were used for parametric and nonparametric comparisons between efAP and tau PET, respectively. Standardized net benefit was used to evaluate improvement in using efAP as an additional copredictor over hippocampal volume in predicting tau PET positivity. Results: Measuring efAP within the hippocampus and summing the first 3 min of brain activity after injection showed the strongest discriminative ability to stratify for tau positivity (AUC, 0.67-0.89 across tau PET Braak regions) in amyloid-positive individuals. Hippocampal efAP correlated significantly with a global tau PET tauopathy score in amyloid-positive participants (r = -0.57, P < 0.0001). Compared with hippocampal volume, hippocampal efAP showed a stronger association with tau PET Braak stage (ρ = -0.58 vs. -0.37) and superior stratification of tau PET tauopathy score (AUC, 0.86 vs. 0.66; P = 0.002). Conclusion: Hippocampal efAP can provide additional information to conventional amyloid PET, including estimation of the likelihood of tau positivity in amyloid-positive individuals.


Assuntos
Doença de Alzheimer , Amiloidose , Disfunção Cognitiva , Tauopatias , Doença de Alzheimer/patologia , Amiloide , Peptídeos beta-Amiloides/análise , Proteínas Amiloidogênicas , Carbolinas , Humanos , Tomografia por Emissão de Pósitrons , Tauopatias/patologia , Proteínas tau
4.
J Alzheimers Dis ; 70(4): 1241-1257, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31322571

RESUMO

BACKGROUND: Tools for efficient evaluation of amyloid- and tau-PET images are needed in both clinical and research settings. OBJECTIVE: This study was designed to validate a semi-automated image analysis methodology, called Biomarker Localization, Analysis, Visualization, Extraction, and Registration (BLAzER). We tested BLAzER using two different segmentation platforms, FreeSurfer (FS) and Neuroreader (NR), for regional brain PET quantification in participants in the Alzheimer's Disease Neuroimaging Initiative (ADNI) dataset. METHODS: 127 amyloid-PET and 55 tau-PET studies with volumetric MRIs were obtained from ADNI. The BLAzER methodology utilizes segmentation of MR images by FS or NR, then visualizes and quantifies regional brain PET data using FDA-cleared software (MIM), enabling quality control to ensure optimal registration and to detect segmentation errors. RESULTS: BLAzER analysis required ∼5 min plus segmentation time. BLAzER using FS segmentation showed strong agreement with ADNI for global amyloid-PET standardized uptake value ratios (SUVRs) (r = 0.9922, p < 0.001) and regional tau-PET SUVRs across all Braak staging regions (r > 0.97, p < 0.001) with high inter-operator reproducibility (ICC > 0.97) and nearly identical dichotomization as amyloid-positive or -negative (2 discrepant cases out of 127). Comparing FS versus NR segmentation with BLAzER, global SUVRs were strongly correlated for amyloid-PET (r = 0.9841, p < 0.001), but were systematically higher (4% on average) with NR, likely due to more inclusion of white matter with NR-defined regions. CONCLUSIONS: BLAzER provides an efficient methodology for regional brain PET quantification. FDA-cleared components and visualization of registration reduce barriers between research and clinical applications.


Assuntos
Doença de Alzheimer/metabolismo , Pesquisa Biomédica/métodos , Encéfalo/metabolismo , Processamento de Imagem Assistida por Computador/métodos , Tomografia por Emissão de Pósitrons/métodos , Idoso , Idoso de 80 Anos ou mais , Doença de Alzheimer/diagnóstico por imagem , Biomarcadores/metabolismo , Encéfalo/diagnóstico por imagem , Feminino , Humanos , Imageamento por Ressonância Magnética/métodos , Masculino , Pessoa de Meia-Idade
5.
Radiol Bras ; 51(1): 13-19, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29559761

RESUMO

OBJECTIVE: To compare an albumin-bound gadolinium chelate (gadofosveset trisodium) and an extracellular contrast agent (gadobenate dimeglumine), in terms of their effects on myocardial longitudinal (T1) relaxation time and partition coefficient. MATERIALS AND METHODS: Study subjects underwent two imaging sessions for T1 mapping at 3 tesla with a modified look-locker inversion recovery (MOLLI) pulse sequence to obtain one pre-contrast T1 map and two post-contrast T1 maps (mean 15 and 21 min, respectively). The partition coefficient was calculated as ΔR1myocardium /ΔR1blood , where R1 is 1/T1. RESULTS: A total of 252 myocardial and blood pool T1 values were obtained in 21 healthy subjects. After gadolinium administration, the myocardial T1 was longer for gadofosveset than for gadobenate, the mean difference between the two contrast agents being -7.6 ± 60 ms (p = 0.41). The inverse was true for the blood pool T1, which was longer for gadobenate than for gadofosveset, the mean difference being 56.5 ± 67 ms (p < 0.001). The partition coefficient (λ) was higher for gadobenate than gadofosveset (0.41 vs. 0.33), indicating slower blood pool washout for gadofosveset than for gadobenate. CONCLUSION: Myocardial T1 times did not differ significantly between gadobenate and gadofosveset. At typical clinical doses of the contrast agents, partition coefficients were significantly lower for the intravascular contrast agent than for the extravascular agent.

6.
Radiol. bras ; 51(1): 13-19, Jan.-Feb. 2018. tab, graf
Artigo em Inglês | LILACS | ID: biblio-896154

RESUMO

Abstract Objective: To compare an albumin-bound gadolinium chelate (gadofosveset trisodium) and an extracellular contrast agent (gadobenate dimeglumine), in terms of their effects on myocardial longitudinal (T1) relaxation time and partition coefficient. Materials and Methods: Study subjects underwent two imaging sessions for T1 mapping at 3 tesla with a modified look-locker inversion recovery (MOLLI) pulse sequence to obtain one pre-contrast T1 map and two post-contrast T1 maps (mean 15 and 21 min, respectively). The partition coefficient was calculated as ΔR1myocardium /ΔR1blood , where R1 is 1/T1. Results: A total of 252 myocardial and blood pool T1 values were obtained in 21 healthy subjects. After gadolinium administration, the myocardial T1 was longer for gadofosveset than for gadobenate, the mean difference between the two contrast agents being −7.6 ± 60 ms (p = 0.41). The inverse was true for the blood pool T1, which was longer for gadobenate than for gadofosveset, the mean difference being 56.5 ± 67 ms (p < 0.001). The partition coefficient (λ) was higher for gadobenate than gadofosveset (0.41 vs. 0.33), indicating slower blood pool washout for gadofosveset than for gadobenate. Conclusion: Myocardial T1 times did not differ significantly between gadobenate and gadofosveset. At typical clinical doses of the contrast agents, partition coefficients were significantly lower for the intravascular contrast agent than for the extravascular agent.


Resumo Objetivo: Avaliar o efeito da utilização de um agente de contraste intravascular baseado em gadolínio quelado a albumina (gadofosveset) no tempo T1 e no coeficiente de partição do miocárdio, quando comparado com um agente de contraste extravascular baseado no gadolínio não quelado a albumina (gadobenato). Materiais e Métodos: Os participantes do estudo foram submetidos a dois exames para aquisições do mapeamento T1 em aparelho de 3 tesla. Utilizando uma sequência de pulso modificada - modified look-locker inversion recovery (MOLLI) -, realizou-se uma etapa pré-contraste e duas etapas pós-contraste do mapa T1 (média de 15 e 21 minutos). O coeficiente de partição foi calculado como: ΔR1miocárdio /ΔR1sangue. Resultados: Um total de 252 valores de mapa T1 no miocárdio e no sangue foi obtido em 21 indivíduos saudáveis. Após a administração do meio de contraste, a diferença média do tempo T1 do miocárdio entre os agentes de contraste foi -7,6 ± 60 ms (p = 0,41) (isto é, gadobenato T1 < gadofosveset T1). Já no sangue, a diferença média de tempo T1 foi 56,5 ± 67 ms (p < 0,001) (isto é, gadobenato T1 > gadofosveset T1). O coeficiente de partição foi maior para o gadobenato (λ = 0,41) do que para o gadofosveset (λ = 0,33), refletindo uma eliminação mais lenta do gadofosveset em comparação com o gadobenato. Conclusão: Os tempos T1 do miocárdio não foram significativamente diferentes entre gadobenato e gadofosveset. Os coeficientes de partição foram significativamente mais baixos para o agente de contraste intravascular em comparação com o agente extravascular em doses clínicas típicas de cada contraste.

7.
Int J Cardiol ; 225: 128-139, 2016 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-27718446

RESUMO

BACKGROUND: We sought to estimate the efficacy and safety outcomes of catheter-directed treatment (CDT) for patients with acute pulmonary embolism (PE). METHODS: We searched SCOPUS for studies reporting outcomes after CDT for acute PE. Studies were categorized in three groups for analyses due to heterogeneity in the classification of acute PE: 1) patients with PE causing right ventricular dysfunction and haemodynamic instability: unstable haemodynamic status, 2) patients with PE causing right ventricular dysfunction where study outcomes were not stratified by haemodynamic status: stable and unstable haemodynamic status, and 3) patients with PE causing right ventricular dysfunction who remained haemodynamically stable: stable haemodynamic status. Efficacy and safety outcomes were estimated and presented as point estimates with 95% confidence intervals. RESULTS: In 35 studies with 1253 patients, 1277 CDTs were performed. The in-hospital mortality rates for the unstable haemodynamic status, stable and unstable haemodynamic status, and stable haemodynamic status groups were 18.1% (7.3-38.2%), 7.1% (5.0-10.1%), and 2.6% (0.8-7.3%), respectively. The major bleeding rates across the groups were estimated to be 4.5, 8.5 and 3.9 per 100 CDTs, respectively. Minor bleeding occurred in 6.2, 11.9 and 9.1 per 100 CDTs, respectively. After CDT, all groups had improvements in mean pulmonary artery pressure and right ventricular function. CONCLUSIONS: We provide descriptive measures of efficacy and safety for patients who underwent CDT for acute PE.


Assuntos
Cateterismo/métodos , Embolia Pulmonar/fisiopatologia , Embolia Pulmonar/terapia , Doença Aguda , Cateterismo/efeitos adversos , Cateterismo/tendências , Ensaios Clínicos como Assunto/métodos , Hemorragia/etiologia , Hemorragia/fisiopatologia , Hemorragia/prevenção & controle , Humanos , Embolia Pulmonar/epidemiologia , Resultado do Tratamento , Disfunção Ventricular Direita/epidemiologia , Disfunção Ventricular Direita/fisiopatologia , Disfunção Ventricular Direita/terapia
8.
BMC Cardiovasc Disord ; 16: 58, 2016 Mar 22.
Artigo em Inglês | MEDLINE | ID: mdl-27004532

RESUMO

BACKGROUND: Three tesla (3T) coronary magnetic resonance angiography (MRA) may be optimized using gadolinium-based contrast agents (GBCA) such as gadofosveset trisodium. The goal of this study was to evaluate if there is a qualitative or quantitative improvement in the coronary arteries with variation in contrast dose. METHODS: Twenty-eight healthy volunteers were prospectively recruited for coronary MRA at 3T using a steady state injection technique for 3D radial whole-heart image acquisition with retrospective respiratory self-gating (ClinicalTrials.gov identifier: NCT01853592). Nineteen volunteers completed both single- and double-dose imaging instances (0.03 and 0.06 mmol/kg, respectively). Intra-individual comparison of image quality was assessed by measurement of apparent signal/contrast-to-noise ratio (aSNR/aCNR) and subjective evaluation of image quality by 2 independent reviewers. RESULTS: The average duration of coronary MRA acquisition was 7.2 ± 1.2 min. There was significantly higher (60 %, p < 0.001) aSNR of the aorta and right/left ventricle for the double dose compared to single dose injection scheme and aSNR of the coronary arteries increased by 70 % (p < 0.001) for the double dose injection. aCNR increased by +55 % and +60 % in the ventricles and coronary arteries, respectively (p < 0.001). Overall segmental artery visualization for single dose was possible 47 % of the time, which improved to 60 % with double dose (p = 0.019), predominantly driven by improvements in more distal segment visualization (+40 % improvement in mid arterial segments, p = 0.013). CONCLUSIONS: Gadofosveset trisodium dose of 0.06 mmol/kg significantly quantitatively and qualitatively improves the coronary artery image quality compared to 0.03 mmol/kg at 3T for moderate duration (6-8 min) steady state contrast enhanced coronary MRA.


Assuntos
Meios de Contraste/administração & dosagem , Angiografia Coronária/métodos , Vasos Coronários/diagnóstico por imagem , Gadolínio/administração & dosagem , Angiografia por Ressonância Magnética/métodos , Compostos Organometálicos/administração & dosagem , Adulto , Meios de Contraste/efeitos adversos , Feminino , Gadolínio/efeitos adversos , Voluntários Saudáveis , Humanos , Interpretação de Imagem Assistida por Computador , Masculino , Compostos Organometálicos/efeitos adversos , Valor Preditivo dos Testes , Estudos Prospectivos , Razão Sinal-Ruído , Fatores de Tempo , Adulto Jovem
9.
PLoS One ; 11(1): e0146617, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-26756205

RESUMO

Glioblastoma multiforme is a malignant brain tumor with poor prognosis and high morbidity due to its invasiveness. Hypoxia-driven motility and concentration-driven motility are two mechanisms of glioblastoma multiforme invasion in the brain. The use of anti-angiogenic drugs has uncovered new progression patterns of glioblastoma multiforme associated with significant differences in overall survival. Here, we apply a mathematical model of glioblastoma multiforme growth and invasion in humans and design computational trials using agents that target angiogenesis, tumor replication rates, or motility. The findings link highly-dispersive, moderately-dispersive, and hypoxia-driven tumors to the patterns observed in glioblastoma multiforme treated by anti-angiogenesis, consisting of progression by Expanding FLAIR, Expanding FLAIR + Necrosis, and Expanding Necrosis, respectively. Furthermore, replication rate-reducing strategies (e.g. Tumor Treating Fields) appear to be effective in highly-dispersive and moderately-dispersive tumors but not in hypoxia-driven tumors. The latter may respond to motility-reducing agents. In a population computational trial, with all three phenotypes, a correlation was observed between the efficacy of the rate-reducing agent and the prolongation of overall survival times. This research highlights the potential applications of computational trials and supports new hypotheses on glioblastoma multiforme phenotypes and treatment options.


Assuntos
Neoplasias Encefálicas/tratamento farmacológico , Neoplasias Encefálicas/patologia , Movimento Celular , Ensaios Clínicos como Assunto , Simulação por Computador , Glioblastoma/tratamento farmacológico , Glioblastoma/patologia , Hipóxia Celular , Proliferação de Células , Progressão da Doença , Humanos , Recidiva Local de Neoplasia/tratamento farmacológico , Neovascularização Patológica/tratamento farmacológico , Fenótipo , Recidiva , Reprodutibilidade dos Testes , Análise de Sobrevida
10.
BMC Cardiovasc Disord ; 15: 177, 2015 Dec 22.
Artigo em Inglês | MEDLINE | ID: mdl-26695065

RESUMO

BACKGROUND: The purpose of this study was to define an optimal injection protocol for 5-10 min duration navigator-based coronary MR angiography using an intravascular gadolinium-based contrast agent (GBCA), which is better suited for steady-state coronary MR angiography than conventional GBCAs. METHODS: Using projections from pharmacokinetic models of the intravascular concentration of gadofosveset, a dual-injection protocol was formulated and tested on 14 healthy human subjects. Modified Look-Locker inversion recovery (MOLLI) sequences were used for T1 mapping at 3 Tesla to evaluate the concentration of tracer in the aorta over the scanning interval. RESULTS: Pharmacokinetic models for a bolus plus slow infusion technique at a 5, 10, and 15 min steady state intravascular concentration was compared to single bolus curves. The 70 %/30 % bolus/slow infusion technique resulted in the highest intravascular concentration over a 5 min scan duration. Similarly, the 60 %/40 % bolus/slow infusion technique was projected to be ideal for image acquisition duration of 5-10 min. These models were confirmed with T1 maps on normal volunteers. Arterial-venous mixing of contrast was achieved within 90 s of the beginning of the bolus. CONCLUSIONS: Gadofosveset injection is optimized for the lowest intravascular T1 time for 5-10 min duration MR angiography by bolus injection of 60-70 % of the total dose followed by slow infusion of the remainder of the total dose. This protocol achieves rapid and prolonged steady state intravascular concentrations of the GBCA that may be useful for prolonged image acquisition, such as required for navigator-based coronary MR angiography at 3 Tesla. TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT01130545 NCT01130545 , registered as of May 25, 2010.


Assuntos
Meios de Contraste/administração & dosagem , Angiografia Coronária/métodos , Vasos Coronários/patologia , Gadolínio/administração & dosagem , Angiografia por Ressonância Magnética/métodos , Compostos Organometálicos/administração & dosagem , Adulto , Meios de Contraste/farmacocinética , Esquema de Medicação , Estudos de Viabilidade , Feminino , Gadolínio/sangue , Gadolínio/farmacocinética , Voluntários Saudáveis , Humanos , Infusões Parenterais , Injeções , Masculino , Modelos Biológicos , Compostos Organometálicos/sangue , Compostos Organometálicos/farmacocinética , Valor Preditivo dos Testes , Estudos Prospectivos
11.
J Infect Dis ; 212(10): 1544-51, 2015 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-25964507

RESUMO

BACKGROUND: Impaired cardiac function persists in the era of effective human immunodeficiency virus (HIV) therapy, although the etiology is unclear. We used magnetic resonance imaging (MRI) to measure intramyocardial lipid levels and fibrosis as possible contributors to HIV-associated myocardial dysfunction. METHODS: A cross-sectional study of 95 HIV-infected and 30 matched-healthy adults, without known cardiovascular disease (CVD) was completed. Intramyocardial lipid levels, myocardial fibrosis, and cardiac function (measured on the basis of strain) were quantified by MRI. RESULTS: Systolic function was significantly decreased in HIV-infected subjects as compared to controls (mean radial strain [±SD], 21.7 ± 8.6% vs 30.5 ± 14.2%; P = .004). Intramyocardial lipid level and fibrosis index were both increased in HIV-infected subjects as compared to controls (P ≤ .04 for both) and correlated with the degree of myocardial dysfunction measured by strain parameters. Intramyocardial lipid levels correlated positively with antiretroviral therapy duration and visceral adiposity. Further, impaired myocardial function was strongly correlated with increased monocyte chemoattractant protein 1 levels (r = 0.396, P = .0002) and lipopolysaccharide binding protein levels (r = 0.25, P = .02). CONCLUSIONS: HIV-infected adults have reduced myocardial function as compared to controls in the absence of known CVD. Decreased cardiac function was associated with abnormal myocardial tissue composition characterized by increased lipid levels and diffuse myocardial fibrosis. Metabolic alterations related to antiretroviral therapy and chronic inflammation may be important targets for optimizing long-term cardiovascular health in HIV-infected individuals.


Assuntos
Fibrose/patologia , Infecções por HIV/complicações , Cardiopatias/patologia , Cardiopatias/fisiopatologia , Testes de Função Cardíaca , Miocárdio/patologia , Adulto , Estudos de Casos e Controles , Estudos Transversais , Feminino , Humanos , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade
12.
Radiology ; 277(1): 88-94, 2015 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-25853636

RESUMO

PURPOSE: To investigate the use of cine multidetector computed tomography (CT) to detect changes in myocardial function in a swine cardiomyopathy model. MATERIALS AND METHODS: All animal protocols were in accordance with the Principles for the Utilization and Care of Vertebrate Animals Used in Testing Research and Training and approved by the University of Missouri Animal Care and Use Committee. Strain analysis of cine multidetector CT images of the left ventricle was optimized and analyzed with feature-tracking software. The standard of reference for strain was harmonic phase analysis of tagged cardiac magnetic resonance (MR) images at 3.0 T. An animal model of cardiomyopathy was imaged with both cardiac MR and 320-section multidetector CT at a temporal resolution of less than 50 msec. Three groups were evaluated: control group (n = 5), aortic-banded myocardial hypertrophy group (n = 5), and aortic-banded and cyclosporine A- treated cardiomyopathy group (n = 5). Histologic samples of the myocardium were obtained for comparison with strain results. Dunnett test was used for comparisons of the concentric remodeling group and eccentric remodeling group against the control group. RESULTS: Collagen volume fraction ranged from 10.9% to 14.2%; lower collagen fraction values were seen in the control group than in the cardiomyopathy groups (P < .05). Ejection fraction and conventional metrics showed no significant differences between control and cardiomyopathy groups. Radial strain for both cardiac MR and multidetector CT was abnormal in both concentric (cardiac MR 25.1% ± 4.2; multidetector CT 28.4% ± 2.8) and eccentric (cardiac MR 23.2% ± 2.0; multidetector CT 24.4% ± 2.1) remodeling groups relative to control group (cardiac MR 18.9% ± 1.9, multidetector CT 22.0% ± 1.7, P < .05, all comparisons). Strain values for multidetector CT versus cardiac MR showed better agreement in the radial direction than in the circumferential direction (r = 0.55, P = .03 vs r = 0.40, P = .13, respectively). CONCLUSION: Multidetector CT strain analysis has potential to identify regional wall-motion abnormalities in cardiomyopathy that is not otherwise detected using conventional metrics of myocardial function.


Assuntos
Cardiomiopatias/diagnóstico , Cardiomiopatias/fisiopatologia , Imageamento por Ressonância Magnética , Tomografia Computadorizada Multidetectores , Miocárdio/patologia , Animais , Fenômenos Biomecânicos , Técnicas de Imagem Cardíaca , Modelos Animais de Doenças , Fibrose , Masculino , Suínos , Porco Miniatura
13.
J Cardiovasc Magn Reson ; 15: 64, 2013 Jul 26.
Artigo em Inglês | MEDLINE | ID: mdl-23890156

RESUMO

BACKGROUND: Cardiovascular magnetic resonance (CMR) T1 mapping indices, such as T1 time and partition coefficient (λ), have shown potential to assess diffuse myocardial fibrosis. The purpose of this study was to investigate how scanner and field strength variation affect the accuracy and precision/reproducibility of T1 mapping indices. METHODS: CMR studies were performed on two 1.5T and three 3T scanners. Eight phantoms were made to mimic the T1/T2 of pre- and post-contrast myocardium and blood at 1.5T and 3T. T1 mapping using MOLLI was performed with simulated heart rate of 40-100 bpm. Inversion recovery spin echo (IR-SE) was the reference standard for T1 determination. Accuracy was defined as the percent error between MOLLI and IR-SE, and scan/re-scan reproducibility was defined as the relative percent mean difference between repeat MOLLI scans. Partition coefficient was estimated by ΔR1myocardium phantom/ΔR1blood phantom. Generalized linear mixed model was used to compare the accuracy and precision/reproducibility of T1 and λ across field strength, scanners, and protocols. RESULTS: Field strength significantly affected MOLLI T1 accuracy (6.3% error for 1.5T vs. 10.8% error for 3T, p<0.001) but not λ accuracy (8.8% error for 1.5T vs. 8.0% error for 3T, p=0.11). Partition coefficients of MOLLI were not different between two 1.5T scanners (47.2% vs. 47.9%, p=0.13), and showed only slight variation across three 3T scanners (49.2% vs. 49.8% vs. 49.9%, p=0.016). Partition coefficient also had significantly lower percent error for precision (better scan/re-scan reproducibility) than measurement of individual T1 values (3.6% for λ vs. 4.3%-4.8% for T1 values, approximately, for pre/post blood and myocardium values). CONCLUSION: Based on phantom studies, T1 errors using MOLLI ranged from 6-14% across various MR scanners while errors for partition coefficient were less (6-10%). Compared with absolute T1 times, partition coefficient showed less variability across platforms and field strengths as well as higher precision.


Assuntos
Fibrose Endomiocárdica/diagnóstico , Imageamento por Ressonância Magnética/instrumentação , Meios de Contraste , Modelos Lineares , Imagens de Fantasmas , Reprodutibilidade dos Testes
14.
Int J Cardiovasc Imaging ; 29(5): 1085-94, 2013 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-23515949

RESUMO

Gadolinium enhanced coronary magnetic resonance angiography (MRA) at 3 T appears to be superior to non-contrast methods. Gadofosveset is an intravascular contrast agent that may be well suited to this application. The purpose of this study was to perform an intra-individual comparison of gadofosveset and gadobenate for coronary MRA at 3 T. In this prospective randomized study, 22 study subjects [8 (36%) male; 27.9 ± 6 years; BMI = 22.8 ± 2 kg/m(2)] underwent two studies using a contrast-enhanced inversion recovery three-dimensional fast low angle shot MRA at 3 T. The order of contrast agent administration was varied randomly, separated by an average of 30 ± 5 days, using either gadobenate dimeglumine (Gd-BOPTA; Bracco, 0.1 mmol/Kg) or gadofosveset trisodium (MS-325; Lantheus Med, 0.03 mmol/Kg). Acquisition time, signal-to-noise ratio (SNR) of coronary vessels and contrast-to-noise ratio (CNR) were evaluated. Of 308 coronary arteries and veins segment analyzed, overall SNR of coronary arteries and veins segments were not different for the two contrast agents (132 ± 79 for gadofosveset vs. 135 ± 78 for gadobenate, p = 0.69). Coronary artery CNR was greater for gadofosveset in comparison to gadobenate (73.5 ± 46.9 vs. 59.3 ± 75.7 respectively, p = 0.03). Gadofosveset-enhanced MRA images displayed better image quality than gadobenate-enhanced MRA images (2.77 ± 0.61 for gadofosveset vs. 2.11 ± 0.51, p < .001). Inter- and intra-reader variability was excellent (ICC > 0.90) for both contrast agents. Gadofosveset trisodium appears to show slightly better performance for coronary MRA at 3 T compared to gadobenate.


Assuntos
Meios de Contraste , Vasos Coronários/anatomia & histologia , Gadolínio , Angiografia por Ressonância Magnética/métodos , Meglumina/análogos & derivados , Compostos Organometálicos , Adulto , Feminino , Voluntários Saudáveis , Humanos , Masculino , Maryland , Variações Dependentes do Observador , Valor Preditivo dos Testes , Estudos Prospectivos , Reprodutibilidade dos Testes , Razão Sinal-Ruído , Adulto Jovem
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