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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
31

Domain Adaptation for Multi-Contrast Image Segmentation in Cardiac Magnetic Resonance Imaging / Domänanpassning för segmentering av bilder med flera kontraster vid Magnetresonanstomografi av hjärta

Proudhon, Thomas January 2023 (has links)
Accurate segmentation of the ventricles and myocardium on Cardiac Magnetic Resonance (CMR) images is crucial to assess the functioning of the heart or to diagnose patients suffering from myocardial infarction. However, the domain shift existing between the multiple sequences of CMR data prevents a deep learning model trained on a specific contrast to be used on a different sequence. Domain adaptation can address this issue by alleviating the domain shift between different CMR contrasts, such as Balanced Steady-State Free Precession (bSSFP) and Late Gadolinium Enhancement (LGE) sequences. The aim of the degree project “Domain Adaptation for Multi-Contrast Image Segmentation in Cardiac Magnetic Resonance Imaging” is to apply domain adaptation to perform unsupervised segmentation of cardiac structures on LGE sequences. A style-transfer model based on generative adversarial networks is trained to achieve modality-to-modality translation between LGE and bSSFP contrasts. Then, a supervised segmentation model is developed to segment the myocardium, left and right ventricles on bSSFP data. Final segmentation is performed on synthetic bSSFP obtained by translating LGE images. Our method shows a significant increase in Dice score compared to direct segmentation of LGE data. In conclusion, the results demonstrate that using domain adaptation based on information from complementary CMR sequences is a successful approach to unsupervised segmentation of Late Gadolinium Enhancement images.
32

High-field Cardiac Magnetic Resonance Imaging in Small Animal Models of Cardiovascular Disease

Citro, Lucas Abraham 05 July 2013 (has links)
No description available.
33

Analyse quantitative des paramètres issus de l'IRM cardiaque / Quantitative analysis in cardiac magnetic resonance imaging and prognosis

Bière, Loïc 04 May 2015 (has links)
L'IRM cardiaque est un examen non invasif qui permet aujourd’hui de proposer une analyse multiparamétrique alliant notamment fonction, caractérisation tissulaire, perfusion, et appréciation de la fibrose. Cependant afin d'uniformiser ces analyses il convient de favoriser une interprétation objective des images obtenues passant par une étape de quantification de l'information. Nous avons suivi une cohorte de 195 patients ayant présenté un premier infarctus du myocarde avec sus décalage du segment ST et ayant bénéficié d'une revascularisation coronaire en phase aigüe avec succès. Des IRM ont été réalisées au cours de leur hospitalisation puis à 3 mois. Ont été investigués de façon quantitative les volumes ventriculaires, le stress pariétal systolique, la taille d'infarctus, la taille d'obstruction microvasculaire et la taille de l'épanchement péricardique. Une cohorte de 42 patients présentant une cardiomyopathie hypertrophique a également été étudiée par ECG et IRM. Nous avons débuté par une validation clinique comparative des méthodes de quantification semi-automatique de la taille d'infarctus. L’obtention du seuil par la méthode FWHM permet de mesurer la taille d’infarctus initial la mieux corrélée aux volumes ventriculaires à 3 mois. Nous avons également confronté et souligné les relations entre l’ECG et le phénotype des cardiomyopathies hypertrophiques documenté par IRM cardiaque. Nous montrons qu’il n’existe pas de critère ECG corrélé à la présence de fibrose myocardique dans cette pathologie ; à l’inverse la présence d’une onde q semble en relation avec la géométrie cardiaque tel qu’un rapport de la paroi septale sur latérale élevé. Nous avons également montré que les composantes de la déformation myocardique étaient altérées selon le degré de fibrose myocardique dans le post-infarctus. Nous montrons une altération plus marquée en cas d’obstruction microvasculaire et un caractère prédictif du strain longitudinal global pour la taille d’infarctus à 3 mois. Nos analyses soulignent l'intérêt d'une approche multiparamétrique pour préciser les déterminants d'une part de l'insuffisance cardiaque, d'autre part de la constitution d'un épanchement péricardique post-infarctus. Alors que la taille d’infarctus initiale est le meilleur marqueur de risque de développer un épisode d’insuffisance cardiaque pendant l’hospitalisation, c’est le stress pariétal systolique qui est le mieux relié aux épisodes d’insuffisance cardiaque après la sortie. Enfin, un épanchement péricardique était retrouvé chez 58.5% des patients avec une moyenne de 31.6±24.0 ml. Les paramètres associés en analyse multivariée étaient la taille d’infarctus, la présence d’une obstruction microvasculaire et le stress pariétal systolique. L’ensemble de nos résultats montre l’intérêt d’une approche quantitative et multiparamétrique de l’IRM cardiaque. Ses potentielles applications sont nombreuses dans le domaine de la recherche aussi bien descriptive que prospective et randomisée. / The various aspect of cardiac function may now be investigated non-invasively by cardiac imaging. Cardiac magnetic resonance (CMR) allows to study multiple parameters in one time, including function, perfusion, tissular characteristics and fibrosis. There is a need to propose adequate and objective criteria for CMR analysis, which may be warranted by a quantitative analysis. We prospectively followed 195 patients with a first ST elevation myocardial infarction and successful revascularisation. CMR were performed at baseline and 3 months. We analysed ventricular volumes, systolic wall stress, infarct size, microvascular obstruction, and pericardial effusion extent. A cohort of 42 patients with hypertrophic cardiomyopathy were also studied. We demonstrated the clinical interest for semi-automated analysis of late gadolinium enhancement imaging. The use of the FWHM algorithm appeared strongly related to left ventricular volumes at 3 months. Then we depicted the lack of relationships between electrocardiograms and fibrosis in patients with hypertrophic cardiomyopathy. The presence of q waves appeared to be related to cardiac phenotype, namely higher septal to posterior ratios. We showed the impairment of myocardial deformations in regard of myocardial fibrosis following a myocardial infarction. We found a much depressed deformation in case of microvascular obstruction and an interest for longitudinal global strain for the prediction of infarct size at 3 months. We also studied the determinants of post-infarction heart failure on one part, pericardial effusion on the other, by the use of a CMR multiparametric approach. Infarct size and systolic wall stress were the best markers of in-hospital and post-discharge heart failure, respectively. A pericardial effusion was found in 58.5% of the patients with a mean size of 31.6±24.0 ml. The determinants by multivariate analysis were infarct size, microvascular obstruction and systolic wall stress. Our results highlighted the interest for a quantitative and multiparametric approach of CMR. Further applications are expected in both descriptive and randomized studies.
34

Avaliação da perfusão e do metabolismo glicolítico miocárdicos na miocardiopatia não-compactada isolada / Evaluation of myocardial perfusion and glycolytic metabolism in isolated non-compacted cardiomyopathy

Melo, Marcelo Dantas Tavares de 29 September 2017 (has links)
Introdução: O miocárdio não-compactado é uma doença genética rara de fisiopatologia desconhecida e controversa. Vários fatores têm sido implicados na fisiopatologia, como a disfunção da microcirculação, a perda da torção ventricular, distúrbios mitocondriais e mutações. A alteração do metabolismo cardíaco ocorre precocemente a disfunção diastólica e sistólica, reforçando a relevância desse estudo na análise combinada de tomografia de emissão de pósitron (PET) com 18F-Fluor-2-desoxiglicose e cintilografia de perfusão miocárdica com 99mTc-sestamibi pela tomografia por emissão de fóton simples (SPECT) e suas implicações clínicas. Métodos: Trinta pacientes com miocárdio não-compactado (41 ± 12 anos, 53% do sexo masculino), diagnosticados pelos critérios da ressonância magnética cardíaca, e 8 indivíduos saudáveis (42 ± 12 anos, 50% do sexo masculino) foram recrutados prospectivamente para serem submetidos a análise de perfusão miocárdica pelo SPECT e da captação miocárdica de glicose marcada pela PET. Resultados: Os pacientes apresentaram valores de captação de glicose miocárdica (CMG) menor que os controles (36.9 +- 8.8 vs. 44.6 +- 5.4 umol/min/100g, respectivamente, P = 0.02). Analisando a captação nos 17 segmentos de ambos os grupos, a CGM foi significativamente reduzida em 8 segmentos dos pacientes (P < 0,05). A diferença da média da captação miocárdica de glicose de todos os segmentos do grupo controle em relação a média dos segmentos compactados dos pacientes foi de 8,3 ?mol/min/100g (p < 0,001). Déficit de perfusão foi demonstrado em 15 (50%) dos pacientes, correspondendo a 45 segmentos do ventrículo esquerdo, destes 64,4% com padrão match e 35,6% com padrão mismatch pela análise de perfusão e metabolismo cardíaco. Nas análises univariada e multivariada foram observadas que o betabloqueador aumenta a CMG (coeficiente beta = 10.1, P = 0.008), como também ocorre um aumento gradual da CMG naqueles com doses mais elevadas (P para tendência linear = 0.01). Conclusão: A redução da captação miocárdica de glicose suporta a hipótese de que um mecanismo metabólico celular possa ter um papel na fisiopatologia do miocárdio não compactado. O betabloqueador demonstrou um efeito incremental dosedependente na captação miocárdica de glicose nos pacientes com miocárdio não-compactado, essa modulação do substrato cardíaco necessita de mais estudos para comprovação do benefício clínico nessa população / Background: Noncompaction cardiomyopathy (NCC) is a rare genetic disease with unknown and controversial pathophysiology. Several factors have been implicated such as microvascular dysfunction, loss of ventricular torsion, mitochondrial disorders, and genetic mutations. The change in cardiac metabolism occurs before the diastolic and systolic dysfunction, reinforcing the relevance of this study by the combined analysis of positron emission tomography with 18F-Fluor-2-deoxyglucose (PET) and myocardial perfusion scintigraphy with 99mTc-sestamibi by single-photon emission computed tomography (SPECT) and their clinical implications. Methods: Thirty patients (41 ± 12 years, 53% male) with NCC, diagnosed by cardiovascular magnetic resonance criteria, and 8 age-matched healthy controls (42 ± 12 years, 50% male) were prospectively recruited to undergo FDG-PET with measurement of the myocardial glucose uptake rate (MGU) and SPECT in order to investigate perfusion-metabolism patterns. Result: Patients with LVNC had lower global MGU compared with that in controls (36.9 +- 8.8 vs. 44.6 +- 5.4 +-mol/min/100g, respectively, P = 0.02). Of 17 LV segments, MGU levels were significantly reduced in 8, and also a reduction was observed when compacted segments from LVNC were compared with the segments from control subjects (P < 0,05). The difference in mean myocardial glucose uptake of all segments of the control group compared to the mean of the compact segments of the patients was 8.3 ?mol/min/100g (p < 0,001). Perfusion defects were also found in 15 (50%) patients (45 LV segments: 64.4% match, and 35.6% mismatch perfusionmetabolism pattern). Univariate and multivariate analyses showed that betablocker therapy was associated with increased MGU (beta coefficient=10.1, P = 0.008). Moreover, a gradual increase occurred in MGU across the beta-blocker dose groups (P for trend = 0.01). Conclusions: The reduction of MGU documented by FDG-PET in LVNC supports the hypothesis that a cellular metabolic pathway may play a role in the pathophysiology of LVNC. Betablocker demonstrated an incremental dose-dependent effect on myocardial glucose uptake in patients with NCC. The beneficial effect of beta-blocker mediating myocardial metabolism in the clinical course of LVNC requires further investigation
35

Avaliação de fibrose miocárdica pelo strain, comparado ao achado de realce tardio da ressonância magnética cardíaca, em pacientes portadores de cardiopatia chagásica crônica / Assessment of myocardial fibrosis by strain, compared with late enhancement by the cardiac magnetic resonance imaging in patients with chronic cardiopathy Chagas\' disease

Paladino Filho, Antonio Tito 07 June 2016 (has links)
Desde o primeiro relato a Doença de Chagas permanece endêmica na América Latina com 18 milhões de pessoas cronicamente infectadas e, aproximadamente, 200.000 novos casos por ano. Doença parasitária causada por Trypanosoma cruzi, tem como transmissor \"natural\" da doença um inseto hematófago, o Reduris (barbeiro). Este inseto se torna infectado ao ingerir o sangue de um animal ou indivíduo infectado com o Trypanosoma cruzi. O contágio ocorre basicamente nas áreas rurais nas quais o homem, frequentemente, está em contato com hospedeiros e vetores ao destruir a mata nativa. Apesar da infecção geralmente ocorrer nos primeiros anos de vida, os pacientes infectados podem manifestar os sinais e sintomas da cardiopatia chagásica até 20 anos mais tarde. O custo propriamente dito e o sofrimento humano representados pela Doença de Chagas são grandes. Medicamentos, internações hospitalares frequentes e tratamento com dispositivos de alto custo (ex: marcapasso/ cardiodesfibrilador). Com quadro clínico insidioso, os pacientes podem apresentar insuficiência cardíaca franca, eventos tromboembólicos, arritmias ventriculares, dor torácica atípica e morte súbita. Seu diagnóstico baseia-se em epidemiologia positiva, anamnese, exame físico, alterações eletrocardiográficas, radiológicas e testes sorológicos. O envolvimento cardíaco é a principal causa de morte, sendo que a fisiopatologia e a evolução clínica da doença não são completamente compreendidas e a estratificação de risco permanece um desafio. A presença de disfunção miocárdica associada ou não à doença arterial aterosclerótica vem acompanhada de áreas de fibrose miocárdica e tem se mostrado como importante fator de pior prognóstico. A Ressonância Magnética Cardíaca (RMC) é um método já consagrado na detecção de fibrose miocárdica pela técnica de realce tardio (RT). Os objetivos dessa tese são: 1-Correlacionar o strain miocárdico nos segmentos do ventrículo esquerdo com as áreas de realce tardio detectadas na Ressonância Magnética Cardíaca, 2- Correlacionar o strain global do ventrículo esquerdo avaliado pela técnica de Speckle Tracking com a extensão de fibrose (numero de segmentos) avaliada pela Ressonância Magnética Cardíaca; 3- Comparar a Fração de ejeção avaliada pelo Ecocardiograma bidimensional e a Ressonância Magnética Cardíaca em pacientes com cardiopatia chagásica crônica; 4- Avaliar se existe relação entre a fração de ejeção avaliada pelo ecocardiograma bidimensional e a extensão de fibrose (número de segmentos) pela Ressonância Cardíaca. Foram selecionados 31 pacientes com o diagnóstico confirmado de Doença de Chagas. 27 pacientes que respeitaram os critérios de inclusão e exclusão, e que assinaram o termo de consentimento livre e esclarecido realizaram Ressonância Magnética Cardíaca com a técnica de realce tardio. De todos os pacientes selecionados, 27 completaram o protocolo da RMC e realizaram em sequencia o Ecocardiograma transtorácico para avaliar o strain miocárdico (speckle tracking) em intervalo máximo de 5 dias. Todos que completaram o protocolo não apresentaram efeitos adversos e os exames foram considerados interpretáveis. Para calcular a amostra de pacientes necessária, os cálculos foram feitos pela estatística de teste t, com distribuição t de Student, para comparação entre duas médias, com poder de teste de 80% e nível de significância de 5%, o que resultou numa estimativa de tamanho mínimo de amostra de 22 lesões por grupo (44 lesões) para que seja possível identificar diferenças significativas em todas as regiões numa amostra com medidas de mesmo comportamento que as observadas em Yajima et al e Jitsuo Higaki et al. Com isso, a amostra mínima seria de 22 pacientes. Para avaliar a concordância entre variáveis quantitativas, utilizou-se o coeficiente de concordância de Lin com intervalo de confiança (IC) 95% estimado segundo método Bootstrap. O coeficiente de concordância de Lin (Rc) combinada precisão e acurácia para determinar se observações desviam-se significativamente da linha de perfeita concordância (linha de 45 graus com origem no 0 dos eixos x e y). O coeficiente de Kappa de Cohen com IC 95% foi utilizado em analises de concordância para variáveis categóricas. Valores de p foram calculados utilizando-se método exato. Os critérios de Landis & Koch foram utilizados na interpretação dos coeficientes de concordância, assim definidos: (a) quase-perfeita, para valores de 0,81 a 1,00; (b) substancial, para valores de 0,61 a 0,80; (c) moderada, para valores entre 0,41 e 0,60; (d) regular, para valores entre 0,21 e 0,40; (d) discreta, para valores de 0 a 0,20. As estimações de intervalos de confiança 95% via bootstrap basearam-se em 1000 replicações. Estimativas de sensibilidade, especificidade, valores preditivo positivo e negativo com IC95% foram determinados. Variáveis quantitativas foram comparadas entre 2 grupos independentes utilizando-se testes não-paramétrico de Mann-Whitney com métodos exatos de cálculo do valor-p. Variáveis quantitativas comparadas com Mann-Whitney foram descritas com mediana e intervalo interquartil. Dado o reduzido tamanho de amostra, analise de regressão logística binaria univariada foi conduzida utilizando método exato. Para covariável quantitativa foi testada, a suposição de linearidade com o log-odds no modelo de regressão logística através da construção de \"Smoothed Scatter Plots\". Quando suposição não foi satisfeita, covariável originalmente quantitativa foi dicotomizadas segundo a mediana da distribuição. Odds ratios e seus respectivos intervalos de confiança 95% foram estimados. Analises de correlação entre variáveis quantitativas foram conduzidas utilizando-se coeficiente de correlação de Spearman(rho)(com IC95%). Forte correlação foi definida como |rho| >=0.70; correlação moderada para 0.5 <= |rho| <0.7 ; correlação fraca a moderada para 0.3<= |rho| <0.5; e fraca para |rho| <0.3. Normalidade foi avaliada com a inspeção visual de histogramas e aplicação do teste de normalidade Shapiro-Wilks. Todos os valores de p apresentados são do tipo bilateral: p < 0.05 e 0.05<p<= 0.10 foram considerados significantes e marginalmente significantes respectivamente. O software R (R Foundation, Vienna, Austria) foi utilizado na análise estatística de dados. Resultados: Dos 27 pacientes do estudo temos a idade média dos pacientes de 53,1 +- 7,0 anos, com mediana de 54 anos, sendo 08 (29,7%) homens e 19 (70,3%) mulheres. A fração de ejeção média pelo ecocardiograma foi de 55,1 +- 14,7%, e pela Ressonância Magnética Cardíaca foi de 55,8 +- 13,4%. O número total de segmentos avaliados foi 453 (98,7%), com interpretação não realizada em apenas 6 segmentos (1,3%) pelo ecocardiograma, de um total de 459. Encontramos realce tardio em 61 segmentos analisados e do total, 86 segmentos apresentaram alteração do strain. Tendo como padrão ouro o realce tardio na RMC, comparamos segmento a segmento o resultado entre essa e o ecocardiograma (speckle tracking). Levamos em conta a literatura que descreve uma prevalência da fibrose em portadores de cardiopatia chagásica crônica de aproximadamente 40%. Com esses dados obtivemos uma sensibilidade de 95%, especificidade de 91%, Valor preditivo positivo de 88,6% e valor preditivo negativo de 96,6%. Correlacionando o Strain Global Longitudinal (SGL) e a extensão (número de segmentos com realce tardio pela RMC) da fibrose neste trabalho, não observou-se diferença nas medianas de número de segmentos na CMR comparadas entre os grupos Strain Global Longitudinal - normal x alterado (p=0.287 , teste exato de Mann-Whitney). Utilizando como limites de fração de ejeção do ventrículo esquerdo >= 55% como normal e <55% alterada, comparamos à extensão de fibrose- numero de segmentos- ( realce tardio) pela CMR. Observou-se uma diferença marginalmente significativa na comparação das medianas do numero de segmentos com realce tardio na CMR entre os 2 grupos (p=0.064). ¹based on exact Mann-Whitney test. Comparamos também a fração de ejeção do ventrículo esquerdo pela RMC e pelo Ecocardiograma transtorácico utilizando o método de Simpson. Ao nível de significância de 5% (coeficiente de Lin), observou-se uma quase perfeita concordância entre FEVE pela Ressonância Magnética Cardíaca e FEVE pelo Ecocardiograma transtorácico utilizando em ambos o método de Simpson. (Rc = 0.9335 IC95% 0.878-0.957; N=27). / Since the first report, Chaga\'s disease remains endemic in Latin America with 18 million chronically infected people and approximately 200,000 new cases per year. Parasitic disease caused by Trypanosoma cruzi, is \"natural\" transmitter disease of a hematophagous insect, the Reduris (barber). This insect becomes infected by ingesting blood of an animal or individual infected with Trypanosoma cruzi. The infection occurs primarily in rural areas where men often are in touch with hosts and vectors by destroying the native forest. Despite the infection usually occurs early in life, infected patients may exhibit signs and symptoms of Chagas disease 20 years later. The cost itself and human suffering represented by Chagas disease are a public issue. Medication, frequent hospitalization and treatment with costly devices (eg pacemaker / defibrillator) are frequently necessary. With insidious clinical signs and symptons, patients may present with heart failure, thromboembolic events, ventricular arrhythmias, atypical chest pain and sudden death. Its diagnosis is based on positive epidemiology, history, physical examination, electrocardiographic, radiological and serological changes. Cardiac involvement is the leading cause of death, and the pathophysiology and clinical course of the disease are not fully understood and the risk stratification remains a challenge. The presence of myocardial dysfunction with or without atherosclerotic arterial disease is accompanied by myocardial fibrosis areas and has been an important factor of poor prognosis. Cardiac Magnetic Resonance (CMR) is a method already established in the detection of myocardial fibrosis by delayed gadolinium enhancement technique (DGE). The objectives of this thesis are: 1-To correlate myocardial strain in left ventricular segments with areas of late enhancement detected in Cardiac Magnetic Resonance, 2- correlate the global left ventricular strain measured by Speckle Tracking technique with fibrosis extension (number of segments) evaluated by Cardiac Magnetic Resonance; 3- Compare the ejection fraction assessed by Two-dimensional echocardiography and cardiac Magnetic Resonance in patients with chronic cardiac Chagas\' disease; 4- To assess whether there is a relationship between the ejection fraction assessed by two-dimensional echocardiography and fibrosis extension (number of segments) by CMR. We selected 31 patients with confirmed diagnosis of Chagas\' disease. 27 patients who complied with the inclusion and exclusion criteria, and who signed the informed consent , performed Cardiac Magnetic Resonance with late gadolinium enhancement (DGE) technique. Of all the selected patients, 27 completed the RMC protocol and were in sequence directed to the transthoracic echocardiogram to assess myocardial strain (speckle tracking) in maximum interval of 5 days. Everyone who completed the protocol showed no adverse effects and the tests were considered interpretable. To calculate the sample required patients, we used the test statistic t, with t Student distribution for comparison between two averages, with the power to test 80% and 5% significance level, which resulted in an estimate minimum sample of 22 injuries per group size (44 injuries) so you can identify significant differences in all regions in a sample with the same measures of behavior than those observed in Yajima et al and Jitsuo Higaki et al. Thus, the minimum sample size would be 22 patients. To evaluate the correlation between quantitative variables, we used the Lin\'s concordance coefficient (1,2) with a confidence interval (CI) 95% estimated second method Bootstrap (4). The correlation coefficient Lin (Rc) combines precision and accuracy to determine if observations deviate significantly from perfect correlation line (45 degree line with origin 0 of the x and y axes). Cohen\'s kappa coefficient with 95% (3) was used for analysis of agreement for categorical variables. P values were calculated using the exact method. The Landis and Koch criteria (5) were used in the interpretation of correlation coefficients defined as follows: (a) quasi-perfect for values 0.81 to 1.00; (b) substantial amounts of 0.61 to the 0.80; (c) Moderate to values between 0.41 and 0.60; (d) regular, to between 0.21 and 0.40; (d) mild to values from 0 to 0.20. The estimation of 95% confidence intervals by bootstrap based on 1000 replicates. Quantitative variables were compared between two independent groups using non-parametric Mann-Whitney test with exact methods of calculating the p-value. (6-8) Quantitative variables compared with Mann-Whitney were described as median and interquartile range. Given the small sample size, regression analysis univariate binary logistic regression was conducted using exact method (9-11). For quantitative covariate was tested, the linearity assumption with the log-odds in the logistic regression model by building \"Smoothed Scatter Plots\". (9) When assumption was not met, originally quantitative covariate was dichotomized according to the median of the distribution. Odds ratios and their 95% confidence intervals were estimated. All significance probabilities (p values) presented are the bilateral type and values less than 0.05 considered statistically significant. The R (R Foundation, Vienna, Austria) software was used for statistical analysis of data. In order to measure the correlation between the results of both tests in the study were calculated sensitivity, specificity, positive predictive value and negative predictive value considering the CMR as the gold standard. Results: Of the 27 study patients have a average age of 53.1 + - 7.0 years and median of 54 years. 08 (29.7%) men and 19 (70.3%) women. The average ejection fraction by echocardiography was 55.1 + - 14.7%, and by Cardiac Magnetic Resonance was 55.8 + - 13.4%. The total number of evaluated segments was 453 (98.7%), with no interpretation performed in only 6 segments (1.3%) on echocardiography, a total of 459 segments. Delayed enhancement by Cardiac Magnetic Ressonance was found in 61 segments analyzed. In the order \"side\" 86 segmets registered an altered strain. As the gold standard the delayed enhancement in the MRC, compared to segment studied segment. We take into account the literature describing the prevalence of fibrosis in patients with chronic Chagas\' heart disease of approximately 40%. With this data we obtained a sensitivity of 95%, specificity 91%, positive predictive value of 88.6% and a negative predictive value of 96.6%. Correlating the Global Longitudinal Strain (SGL) and extent (number of segments with delayed enhancement by CMR) of fibrosis in this study, no difference was observed in the number of segments of medians in the CMR compared between Strain Global Longitudinal groups - Normal x changed (p = 0.287, exact Mann-Whitney). Using as an ejection fraction of the left ventricle limits > = 55% as normal and < 55% changed, compared to the extent of fibrose- number of segments- (delayed enhancement) by CMR. There was a marginally significant difference when comparing the median number of segments with delayed enhancement on CMR between the 2 groups (p = 0.064). ¹based on exact Mann-Whitney test. We also compared the ejection fraction of the left ventricle by CMR and transthoracic echocardiography using the Simpson method. At a significance level of 5% (Lin coefficient), there was an almost perfect correlation between LVEF by Cardiac Magnetic Resonance and LVEF by using transthoracic echocardiography in both the Simpson method. (Rc = 0.9335 95% CI 0878-0957; N = 27)
36

Prognostischer Wert der kardialen Magnetresonanztomographie bei Patienten mit ST-Hebungsinfarkt - Analyse der Parameter linksventrikuläre Ejektionsfraktion, Infarktgröße, mikrovaskuläre Obstruktion und myokardialer „Salvage“ in einer multizentrischen Studie

Sünkel, Henning 07 July 2015 (has links) (PDF)
Die kardiale Magnetresonanztomographie (MRT) ermöglicht nach einem akuten Myokardinfarkt (AMI) die Visualisierung und Quantifizierung der Myokardschädigung anhand verschiedener Parameter wie Ejektionsfraktion (EF), Infarktgröße, Mikrovaskuläre Obstruktion (MO) und „Myocardial Salvage Index“ (MSI). Anhand dieser MRT-Marker kann das Risiko für kardiovaskuläre Komplikationen eingeschätzt werden, was für die Weiterversorgung des Patienten sowie für die kardiologische Forschung von großem Interesse ist. In dieser Arbeit wurde die prognostische Relevanz der MRT-Parameter erstmals in einer großen, multizentrischen Studie untersucht. Zudem sollte unter den vier genannten MRT-Markern derjenige mit der größten prognostischen Aussagekraft ermittelt werden. Dazu wurden 795 Patienten aus der AIDA STEMI Studie einer MRT unterzogen und dann zwölf Monate lang im Hinblick auf den kombinierten Endpunkt „Major Adverse Cardiac Events“ (MACE; bestehend aus Tod, Reinfarkt und Klinikaufnahme wegen Herzinsuffizienz) nachbeobachtet. Die Ergebnisse belegen, dass die genannten MRT-Parameter prognostisch relevant sind und insbesondere die MO und die Infarktgröße einen Einfluss auf die Prognose ausüben, welcher über den Wert etablierter klinischer Risikomarker hinausgeht. Herausragende Bedeutung kommt dabei der MO zu, welche nach multivariater Analyse der potenteste MRT-Prädiktor für kardiovaskuläre Ereignisse ist. Somit sollten die MRT-Parameter in kommenden kardiologischen Studien als Surrogatmarker für klinische Endpunkte berücksichtigt werden. Zudem könnten sie für den klinischen Alltag die Möglichkeit bieten, die Patientenversorgung enger an die individuelle Prognose anzupassen.
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Medidas de par?metros morfol?gicos e funcionais do Cora??o em brasileiros: um subestudo do primeiro registro multic?ntricos latino-americano em resson?ncia magn?tica cardi?ca

Macedo Filho, Robson de 06 May 2013 (has links)
Made available in DSpace on 2014-12-17T14:14:01Z (GMT). No. of bitstreams: 1 RobsonMF_DISSERT.pdf: 1631191 bytes, checksum: 260bb5fe4f1e2f487d506e21842e62a3 (MD5) Previous issue date: 2013-05-06 / Funda??o de Amparo a Pesquisa do Estado de S?o Paulo / There is no data about cardiac measurements em Brazilians obtained by CMR. This a muldisciplinary study with the objective of obtaining measurements of the left ventricle (LV) and right ventricle (RV) diastolic diameter (Dd), systolic diameter (Ds), diastolic volume (Dv), systolic volume (Sv), ejection fraction (EF) and myocardial mass in Brazilians. One hundred and seven (54 men and 53 women, mean age of 43.4 ? 13.1 years) asymptomatic individuals without heart disease were submitted to cardiac magnetic resonance (cMR) studies using steady state free precession technique. The means and standard deviations of the parameters of the LV and RV were respectively: LVDD = 4,8 ? 0,5 cm; LVSD = 3,0?0,6 cm; LVDV = 128,4?29,6 ml; LVSV = 45,2?16,6 ml; LVEF = 65,5?6,3%; LV mass = 95,2?30,8.1 g; RVDD = 3,9?1,3 cm; RVSD = 2,5?0,5 cm; RVDV = 126,5?30,7 ml; RVSV = 53.6?18,4 ml; RVEF = 58.3?8,0.0% and RV mass = 26,1?6,1 g. The masses and volumes were significantly higher in men, except for the LVSV. The RV EF was significantly higher in women. There was inverse correlation between RV systolic volume and with age, being more significant in men. This study describes for the first time benchmarks for cardiac measurements obtained by CMR among asymptomatic Brazilians individuals without heart disease and demonstrated differences according to sex and age / N?o h? dados nacionais sobre medidas card?acas obtidas por Resson?ncia Magn?tica Card?aca (RMc). Esse trabalho multidisciplinar teve como objetivo obter medidas do di?metro diast?lico (Dd), di?metro sist?lico (Ds), volume diast?lico final (VdF), volume sist?lico final (VsF), fra??o de eje??o (FE) e da massa mioc?rdica dos ventr?culos esquerdo (VE) e direito (VD) em brasileiros. Cento e sete (107) indiv?duos, 54 homens e 53 mulheres, com idade m?dia de 43,4 ? 13,1 anos, assintom?ticos e sem cardiopatias, foram submetidos ? RMc, utilizando t?cnica de precess?o livre em estado de equil?brio. As m?dias e os desvios padr?es dos par?metros do VE e VD foram respectivamente: Dd VE = 4,8 ? 0,5 cm; Ds VE = 3,0 ? 0,6 cm; VdF VE = 128,4 ? 29,6 ml; VsF VE = 45,2 ? 16,6 ml; FEVE = 65,5 ? 6,3%; massa do VE = 95,2 ? 30,8 g; Dd VD = 3,9 ? 1,3 cm; Ds VD = 2,5 ? 0,5cm; VdF VD = 126,5 ? 30,7 ml; VsF VD = 53,6 ? 18,4 ml; FEVD = 58,3 ? 8,0% e massa do VD = 26,1 ? 6,1 g. As massas e volumes foram significativamente maiores nos homens, exceto para o VsF do VE. A fra??o de eje??o do VD foi significativamente maior nas mulheres. Houve correla??o significativa e inversa do Vs do VD com o aumento da idade, sendo mais significativo nos homens. Esse estudo descreve, pela primeira vez, medidas card?acas obtidas pela RMc em brasileiros, as quais revelam diferen?as de acordo com o sexo e a idade
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Avaliação de fibrose miocárdica pelo strain, comparado ao achado de realce tardio da ressonância magnética cardíaca, em pacientes portadores de cardiopatia chagásica crônica / Assessment of myocardial fibrosis by strain, compared with late enhancement by the cardiac magnetic resonance imaging in patients with chronic cardiopathy Chagas\' disease

Antonio Tito Paladino Filho 07 June 2016 (has links)
Desde o primeiro relato a Doença de Chagas permanece endêmica na América Latina com 18 milhões de pessoas cronicamente infectadas e, aproximadamente, 200.000 novos casos por ano. Doença parasitária causada por Trypanosoma cruzi, tem como transmissor \"natural\" da doença um inseto hematófago, o Reduris (barbeiro). Este inseto se torna infectado ao ingerir o sangue de um animal ou indivíduo infectado com o Trypanosoma cruzi. O contágio ocorre basicamente nas áreas rurais nas quais o homem, frequentemente, está em contato com hospedeiros e vetores ao destruir a mata nativa. Apesar da infecção geralmente ocorrer nos primeiros anos de vida, os pacientes infectados podem manifestar os sinais e sintomas da cardiopatia chagásica até 20 anos mais tarde. O custo propriamente dito e o sofrimento humano representados pela Doença de Chagas são grandes. Medicamentos, internações hospitalares frequentes e tratamento com dispositivos de alto custo (ex: marcapasso/ cardiodesfibrilador). Com quadro clínico insidioso, os pacientes podem apresentar insuficiência cardíaca franca, eventos tromboembólicos, arritmias ventriculares, dor torácica atípica e morte súbita. Seu diagnóstico baseia-se em epidemiologia positiva, anamnese, exame físico, alterações eletrocardiográficas, radiológicas e testes sorológicos. O envolvimento cardíaco é a principal causa de morte, sendo que a fisiopatologia e a evolução clínica da doença não são completamente compreendidas e a estratificação de risco permanece um desafio. A presença de disfunção miocárdica associada ou não à doença arterial aterosclerótica vem acompanhada de áreas de fibrose miocárdica e tem se mostrado como importante fator de pior prognóstico. A Ressonância Magnética Cardíaca (RMC) é um método já consagrado na detecção de fibrose miocárdica pela técnica de realce tardio (RT). Os objetivos dessa tese são: 1-Correlacionar o strain miocárdico nos segmentos do ventrículo esquerdo com as áreas de realce tardio detectadas na Ressonância Magnética Cardíaca, 2- Correlacionar o strain global do ventrículo esquerdo avaliado pela técnica de Speckle Tracking com a extensão de fibrose (numero de segmentos) avaliada pela Ressonância Magnética Cardíaca; 3- Comparar a Fração de ejeção avaliada pelo Ecocardiograma bidimensional e a Ressonância Magnética Cardíaca em pacientes com cardiopatia chagásica crônica; 4- Avaliar se existe relação entre a fração de ejeção avaliada pelo ecocardiograma bidimensional e a extensão de fibrose (número de segmentos) pela Ressonância Cardíaca. Foram selecionados 31 pacientes com o diagnóstico confirmado de Doença de Chagas. 27 pacientes que respeitaram os critérios de inclusão e exclusão, e que assinaram o termo de consentimento livre e esclarecido realizaram Ressonância Magnética Cardíaca com a técnica de realce tardio. De todos os pacientes selecionados, 27 completaram o protocolo da RMC e realizaram em sequencia o Ecocardiograma transtorácico para avaliar o strain miocárdico (speckle tracking) em intervalo máximo de 5 dias. Todos que completaram o protocolo não apresentaram efeitos adversos e os exames foram considerados interpretáveis. Para calcular a amostra de pacientes necessária, os cálculos foram feitos pela estatística de teste t, com distribuição t de Student, para comparação entre duas médias, com poder de teste de 80% e nível de significância de 5%, o que resultou numa estimativa de tamanho mínimo de amostra de 22 lesões por grupo (44 lesões) para que seja possível identificar diferenças significativas em todas as regiões numa amostra com medidas de mesmo comportamento que as observadas em Yajima et al e Jitsuo Higaki et al. Com isso, a amostra mínima seria de 22 pacientes. Para avaliar a concordância entre variáveis quantitativas, utilizou-se o coeficiente de concordância de Lin com intervalo de confiança (IC) 95% estimado segundo método Bootstrap. O coeficiente de concordância de Lin (Rc) combinada precisão e acurácia para determinar se observações desviam-se significativamente da linha de perfeita concordância (linha de 45 graus com origem no 0 dos eixos x e y). O coeficiente de Kappa de Cohen com IC 95% foi utilizado em analises de concordância para variáveis categóricas. Valores de p foram calculados utilizando-se método exato. Os critérios de Landis & Koch foram utilizados na interpretação dos coeficientes de concordância, assim definidos: (a) quase-perfeita, para valores de 0,81 a 1,00; (b) substancial, para valores de 0,61 a 0,80; (c) moderada, para valores entre 0,41 e 0,60; (d) regular, para valores entre 0,21 e 0,40; (d) discreta, para valores de 0 a 0,20. As estimações de intervalos de confiança 95% via bootstrap basearam-se em 1000 replicações. Estimativas de sensibilidade, especificidade, valores preditivo positivo e negativo com IC95% foram determinados. Variáveis quantitativas foram comparadas entre 2 grupos independentes utilizando-se testes não-paramétrico de Mann-Whitney com métodos exatos de cálculo do valor-p. Variáveis quantitativas comparadas com Mann-Whitney foram descritas com mediana e intervalo interquartil. Dado o reduzido tamanho de amostra, analise de regressão logística binaria univariada foi conduzida utilizando método exato. Para covariável quantitativa foi testada, a suposição de linearidade com o log-odds no modelo de regressão logística através da construção de \"Smoothed Scatter Plots\". Quando suposição não foi satisfeita, covariável originalmente quantitativa foi dicotomizadas segundo a mediana da distribuição. Odds ratios e seus respectivos intervalos de confiança 95% foram estimados. Analises de correlação entre variáveis quantitativas foram conduzidas utilizando-se coeficiente de correlação de Spearman(rho)(com IC95%). Forte correlação foi definida como |rho| >=0.70; correlação moderada para 0.5 <= |rho| <0.7 ; correlação fraca a moderada para 0.3<= |rho| <0.5; e fraca para |rho| <0.3. Normalidade foi avaliada com a inspeção visual de histogramas e aplicação do teste de normalidade Shapiro-Wilks. Todos os valores de p apresentados são do tipo bilateral: p < 0.05 e 0.05<p<= 0.10 foram considerados significantes e marginalmente significantes respectivamente. O software R (R Foundation, Vienna, Austria) foi utilizado na análise estatística de dados. Resultados: Dos 27 pacientes do estudo temos a idade média dos pacientes de 53,1 +- 7,0 anos, com mediana de 54 anos, sendo 08 (29,7%) homens e 19 (70,3%) mulheres. A fração de ejeção média pelo ecocardiograma foi de 55,1 +- 14,7%, e pela Ressonância Magnética Cardíaca foi de 55,8 +- 13,4%. O número total de segmentos avaliados foi 453 (98,7%), com interpretação não realizada em apenas 6 segmentos (1,3%) pelo ecocardiograma, de um total de 459. Encontramos realce tardio em 61 segmentos analisados e do total, 86 segmentos apresentaram alteração do strain. Tendo como padrão ouro o realce tardio na RMC, comparamos segmento a segmento o resultado entre essa e o ecocardiograma (speckle tracking). Levamos em conta a literatura que descreve uma prevalência da fibrose em portadores de cardiopatia chagásica crônica de aproximadamente 40%. Com esses dados obtivemos uma sensibilidade de 95%, especificidade de 91%, Valor preditivo positivo de 88,6% e valor preditivo negativo de 96,6%. Correlacionando o Strain Global Longitudinal (SGL) e a extensão (número de segmentos com realce tardio pela RMC) da fibrose neste trabalho, não observou-se diferença nas medianas de número de segmentos na CMR comparadas entre os grupos Strain Global Longitudinal - normal x alterado (p=0.287 , teste exato de Mann-Whitney). Utilizando como limites de fração de ejeção do ventrículo esquerdo >= 55% como normal e <55% alterada, comparamos à extensão de fibrose- numero de segmentos- ( realce tardio) pela CMR. Observou-se uma diferença marginalmente significativa na comparação das medianas do numero de segmentos com realce tardio na CMR entre os 2 grupos (p=0.064). ¹based on exact Mann-Whitney test. Comparamos também a fração de ejeção do ventrículo esquerdo pela RMC e pelo Ecocardiograma transtorácico utilizando o método de Simpson. Ao nível de significância de 5% (coeficiente de Lin), observou-se uma quase perfeita concordância entre FEVE pela Ressonância Magnética Cardíaca e FEVE pelo Ecocardiograma transtorácico utilizando em ambos o método de Simpson. (Rc = 0.9335 IC95% 0.878-0.957; N=27). / Since the first report, Chaga\'s disease remains endemic in Latin America with 18 million chronically infected people and approximately 200,000 new cases per year. Parasitic disease caused by Trypanosoma cruzi, is \"natural\" transmitter disease of a hematophagous insect, the Reduris (barber). This insect becomes infected by ingesting blood of an animal or individual infected with Trypanosoma cruzi. The infection occurs primarily in rural areas where men often are in touch with hosts and vectors by destroying the native forest. Despite the infection usually occurs early in life, infected patients may exhibit signs and symptoms of Chagas disease 20 years later. The cost itself and human suffering represented by Chagas disease are a public issue. Medication, frequent hospitalization and treatment with costly devices (eg pacemaker / defibrillator) are frequently necessary. With insidious clinical signs and symptons, patients may present with heart failure, thromboembolic events, ventricular arrhythmias, atypical chest pain and sudden death. Its diagnosis is based on positive epidemiology, history, physical examination, electrocardiographic, radiological and serological changes. Cardiac involvement is the leading cause of death, and the pathophysiology and clinical course of the disease are not fully understood and the risk stratification remains a challenge. The presence of myocardial dysfunction with or without atherosclerotic arterial disease is accompanied by myocardial fibrosis areas and has been an important factor of poor prognosis. Cardiac Magnetic Resonance (CMR) is a method already established in the detection of myocardial fibrosis by delayed gadolinium enhancement technique (DGE). The objectives of this thesis are: 1-To correlate myocardial strain in left ventricular segments with areas of late enhancement detected in Cardiac Magnetic Resonance, 2- correlate the global left ventricular strain measured by Speckle Tracking technique with fibrosis extension (number of segments) evaluated by Cardiac Magnetic Resonance; 3- Compare the ejection fraction assessed by Two-dimensional echocardiography and cardiac Magnetic Resonance in patients with chronic cardiac Chagas\' disease; 4- To assess whether there is a relationship between the ejection fraction assessed by two-dimensional echocardiography and fibrosis extension (number of segments) by CMR. We selected 31 patients with confirmed diagnosis of Chagas\' disease. 27 patients who complied with the inclusion and exclusion criteria, and who signed the informed consent , performed Cardiac Magnetic Resonance with late gadolinium enhancement (DGE) technique. Of all the selected patients, 27 completed the RMC protocol and were in sequence directed to the transthoracic echocardiogram to assess myocardial strain (speckle tracking) in maximum interval of 5 days. Everyone who completed the protocol showed no adverse effects and the tests were considered interpretable. To calculate the sample required patients, we used the test statistic t, with t Student distribution for comparison between two averages, with the power to test 80% and 5% significance level, which resulted in an estimate minimum sample of 22 injuries per group size (44 injuries) so you can identify significant differences in all regions in a sample with the same measures of behavior than those observed in Yajima et al and Jitsuo Higaki et al. Thus, the minimum sample size would be 22 patients. To evaluate the correlation between quantitative variables, we used the Lin\'s concordance coefficient (1,2) with a confidence interval (CI) 95% estimated second method Bootstrap (4). The correlation coefficient Lin (Rc) combines precision and accuracy to determine if observations deviate significantly from perfect correlation line (45 degree line with origin 0 of the x and y axes). Cohen\'s kappa coefficient with 95% (3) was used for analysis of agreement for categorical variables. P values were calculated using the exact method. The Landis and Koch criteria (5) were used in the interpretation of correlation coefficients defined as follows: (a) quasi-perfect for values 0.81 to 1.00; (b) substantial amounts of 0.61 to the 0.80; (c) Moderate to values between 0.41 and 0.60; (d) regular, to between 0.21 and 0.40; (d) mild to values from 0 to 0.20. The estimation of 95% confidence intervals by bootstrap based on 1000 replicates. Quantitative variables were compared between two independent groups using non-parametric Mann-Whitney test with exact methods of calculating the p-value. (6-8) Quantitative variables compared with Mann-Whitney were described as median and interquartile range. Given the small sample size, regression analysis univariate binary logistic regression was conducted using exact method (9-11). For quantitative covariate was tested, the linearity assumption with the log-odds in the logistic regression model by building \"Smoothed Scatter Plots\". (9) When assumption was not met, originally quantitative covariate was dichotomized according to the median of the distribution. Odds ratios and their 95% confidence intervals were estimated. All significance probabilities (p values) presented are the bilateral type and values less than 0.05 considered statistically significant. The R (R Foundation, Vienna, Austria) software was used for statistical analysis of data. In order to measure the correlation between the results of both tests in the study were calculated sensitivity, specificity, positive predictive value and negative predictive value considering the CMR as the gold standard. Results: Of the 27 study patients have a average age of 53.1 + - 7.0 years and median of 54 years. 08 (29.7%) men and 19 (70.3%) women. The average ejection fraction by echocardiography was 55.1 + - 14.7%, and by Cardiac Magnetic Resonance was 55.8 + - 13.4%. The total number of evaluated segments was 453 (98.7%), with no interpretation performed in only 6 segments (1.3%) on echocardiography, a total of 459 segments. Delayed enhancement by Cardiac Magnetic Ressonance was found in 61 segments analyzed. In the order \"side\" 86 segmets registered an altered strain. As the gold standard the delayed enhancement in the MRC, compared to segment studied segment. We take into account the literature describing the prevalence of fibrosis in patients with chronic Chagas\' heart disease of approximately 40%. With this data we obtained a sensitivity of 95%, specificity 91%, positive predictive value of 88.6% and a negative predictive value of 96.6%. Correlating the Global Longitudinal Strain (SGL) and extent (number of segments with delayed enhancement by CMR) of fibrosis in this study, no difference was observed in the number of segments of medians in the CMR compared between Strain Global Longitudinal groups - Normal x changed (p = 0.287, exact Mann-Whitney). Using as an ejection fraction of the left ventricle limits > = 55% as normal and < 55% changed, compared to the extent of fibrose- number of segments- (delayed enhancement) by CMR. There was a marginally significant difference when comparing the median number of segments with delayed enhancement on CMR between the 2 groups (p = 0.064). ¹based on exact Mann-Whitney test. We also compared the ejection fraction of the left ventricle by CMR and transthoracic echocardiography using the Simpson method. At a significance level of 5% (Lin coefficient), there was an almost perfect correlation between LVEF by Cardiac Magnetic Resonance and LVEF by using transthoracic echocardiography in both the Simpson method. (Rc = 0.9335 95% CI 0878-0957; N = 27)
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PROPERTIES AND OPTIMIZATION OF RESPIRATORY NAVIGATOR GATING FOR SPIRAL CINE DENSE CARDIAC MRI

Hamlet, Sean Michael 01 January 2017 (has links)
Cardiac magnetic resonance (MR) imaging can non-invasively assess heart function. Displacement encoding with stimulated echoes (DENSE) is an advanced cardiac MR imaging technique that measures tissue displacement and can be used to quantify cardiac mechanics (e.g. strain and torsion). When combined with clinical risk factors, cardiac mechanics have been shown to be better predictors of mortality than traditional measures of heart function. End-expiratory breath-holds are typically used to minimize respiratory motion artifacts. Unfortunately, requiring subjects to breath-hold introduces limitations with the duration of image acquisition and quality of data acquired, especially in patients with limited ability to hold their breath. Thus, DENSE acquisitions often require respiratory navigator gating, which works by measuring the diaphragm during normal breathing and only acquiring data when the diaphragm is within a pre-defined acceptance window. Unfortunately, navigator gating results in long scan durations due to inconsistent breathing patterns. Also, the navigator echo can be used in different ways to accept or reject image data, which creates several navigator configuration options. Each respiratory navigator configuration has distinct advantages and disadvantages that directly affect scan duration and image quality, which can affect derived cardiac mechanics. Scan duration and image quality need to be optimized to improve the clinical utility of DENSE. Thus, the goal of this project was to optimize those parameters. To accomplish this goal, we set out to complete 3 aims: 1) understand how respiratory gating affects the reproducibility of measures of cardiac mechanics, 2) determine the optimal respiratory navigator configuration, and 3) reduce scan duration by developing and using an interactive videogame to optimize navigator efficiency. Aim 1 of this project demonstrated that the variability in torsion, but not strain, could be significantly reduced through the use of a respiratory navigator compared to traditional breath-holds. Aim 2 demonstrated that, among the configuration options, the dual-navigator configuration resulted in the best image quality compared to the reference standard (traditional breath-holds), but also resulted in the longest scan duration. In Aim 3, we developed an interactive breathing-controlled videogame and demonstrated that its use during cardiac MR can significantly reduce scan duration compared to traditional free-breathing and also led to a small improvement in signal-to-noise ratio of the acquired images. In summary, respiratory navigator gating with DENSE 1) reduces the variability in measured LV torsion, 2) results in the best image quality with the dual-navigator configuration, and 3) results in significantly shorter scan durations through the use of an interactive videogame. Selecting the optimal navigator configuration and using an interactive videogame can improve the clinical utility of DENSE.
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Avaliação da perfusão e do metabolismo glicolítico miocárdicos na miocardiopatia não-compactada isolada / Evaluation of myocardial perfusion and glycolytic metabolism in isolated non-compacted cardiomyopathy

Marcelo Dantas Tavares de Melo 29 September 2017 (has links)
Introdução: O miocárdio não-compactado é uma doença genética rara de fisiopatologia desconhecida e controversa. Vários fatores têm sido implicados na fisiopatologia, como a disfunção da microcirculação, a perda da torção ventricular, distúrbios mitocondriais e mutações. A alteração do metabolismo cardíaco ocorre precocemente a disfunção diastólica e sistólica, reforçando a relevância desse estudo na análise combinada de tomografia de emissão de pósitron (PET) com 18F-Fluor-2-desoxiglicose e cintilografia de perfusão miocárdica com 99mTc-sestamibi pela tomografia por emissão de fóton simples (SPECT) e suas implicações clínicas. Métodos: Trinta pacientes com miocárdio não-compactado (41 ± 12 anos, 53% do sexo masculino), diagnosticados pelos critérios da ressonância magnética cardíaca, e 8 indivíduos saudáveis (42 ± 12 anos, 50% do sexo masculino) foram recrutados prospectivamente para serem submetidos a análise de perfusão miocárdica pelo SPECT e da captação miocárdica de glicose marcada pela PET. Resultados: Os pacientes apresentaram valores de captação de glicose miocárdica (CMG) menor que os controles (36.9 +- 8.8 vs. 44.6 +- 5.4 umol/min/100g, respectivamente, P = 0.02). Analisando a captação nos 17 segmentos de ambos os grupos, a CGM foi significativamente reduzida em 8 segmentos dos pacientes (P < 0,05). A diferença da média da captação miocárdica de glicose de todos os segmentos do grupo controle em relação a média dos segmentos compactados dos pacientes foi de 8,3 ?mol/min/100g (p < 0,001). Déficit de perfusão foi demonstrado em 15 (50%) dos pacientes, correspondendo a 45 segmentos do ventrículo esquerdo, destes 64,4% com padrão match e 35,6% com padrão mismatch pela análise de perfusão e metabolismo cardíaco. Nas análises univariada e multivariada foram observadas que o betabloqueador aumenta a CMG (coeficiente beta = 10.1, P = 0.008), como também ocorre um aumento gradual da CMG naqueles com doses mais elevadas (P para tendência linear = 0.01). Conclusão: A redução da captação miocárdica de glicose suporta a hipótese de que um mecanismo metabólico celular possa ter um papel na fisiopatologia do miocárdio não compactado. O betabloqueador demonstrou um efeito incremental dosedependente na captação miocárdica de glicose nos pacientes com miocárdio não-compactado, essa modulação do substrato cardíaco necessita de mais estudos para comprovação do benefício clínico nessa população / Background: Noncompaction cardiomyopathy (NCC) is a rare genetic disease with unknown and controversial pathophysiology. Several factors have been implicated such as microvascular dysfunction, loss of ventricular torsion, mitochondrial disorders, and genetic mutations. The change in cardiac metabolism occurs before the diastolic and systolic dysfunction, reinforcing the relevance of this study by the combined analysis of positron emission tomography with 18F-Fluor-2-deoxyglucose (PET) and myocardial perfusion scintigraphy with 99mTc-sestamibi by single-photon emission computed tomography (SPECT) and their clinical implications. Methods: Thirty patients (41 ± 12 years, 53% male) with NCC, diagnosed by cardiovascular magnetic resonance criteria, and 8 age-matched healthy controls (42 ± 12 years, 50% male) were prospectively recruited to undergo FDG-PET with measurement of the myocardial glucose uptake rate (MGU) and SPECT in order to investigate perfusion-metabolism patterns. Result: Patients with LVNC had lower global MGU compared with that in controls (36.9 +- 8.8 vs. 44.6 +- 5.4 +-mol/min/100g, respectively, P = 0.02). Of 17 LV segments, MGU levels were significantly reduced in 8, and also a reduction was observed when compacted segments from LVNC were compared with the segments from control subjects (P < 0,05). The difference in mean myocardial glucose uptake of all segments of the control group compared to the mean of the compact segments of the patients was 8.3 ?mol/min/100g (p < 0,001). Perfusion defects were also found in 15 (50%) patients (45 LV segments: 64.4% match, and 35.6% mismatch perfusionmetabolism pattern). Univariate and multivariate analyses showed that betablocker therapy was associated with increased MGU (beta coefficient=10.1, P = 0.008). Moreover, a gradual increase occurred in MGU across the beta-blocker dose groups (P for trend = 0.01). Conclusions: The reduction of MGU documented by FDG-PET in LVNC supports the hypothesis that a cellular metabolic pathway may play a role in the pathophysiology of LVNC. Betablocker demonstrated an incremental dose-dependent effect on myocardial glucose uptake in patients with NCC. The beneficial effect of beta-blocker mediating myocardial metabolism in the clinical course of LVNC requires further investigation

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