Thesis (M.A.)--Boston University / PLEASE NOTE: Boston University Libraries did not receive an Authorization To Manage form for this thesis or dissertation. It is therefore not openly accessible, though it may be available by request. If you are the author or principal advisor of this work and would like to request open access for it, please contact us at open-help@bu.edu. Thank you. / Cardiac Magnetic Resonance Imaging (CMRI) is an important and valuable tool in the routine management of patients with cardiovascular disease. Contrast enhanced CMRI allows detection of ischemic and scarred myocardium, including rare infiltrative processes that cause cardiomyopathies. Amyloidosis comprises a group of diseases that are characterized by the extracellular deposition of insoluble fibrillar proteins in organs. The deposition of amyloid material in the heart leads to presentations of congestive heart failure mainly of the restrictive infiltrative pattern. There may be also conduction abnormalities. Dilated cardiomyopathy is a form of cardiomyopathy that is characterized by abnormal dilatation of the heart and subsequent heart failure. One of the characteristics of the cardiomyopathies and amyloidosis is the diffuse interstitial or replacement myocardial fibrosis. Myocardial fibrosis leads to impaired cardiac diastolic and systolic function and can lead to increased cardiovascular morbidity and mortality. Cardiac Magnetic Resonance Imaging (CMRI) with contrast can be used to characterize the extent of myocardial fibrosis through T1 mapping and as such it can be used as a prognostic indicator in amyloidosis and dilated cardiomyopathy. / 2031-01-02

Cardiovascular disease remains a leading a cause of mortality and morbidity. Primary prevention is known to reduce the incidence of cardiovascular disease. The use of medication is currently targeted at those at increased predicted risk of cardiovascular disease using risk prediction tools developed from large epidemiological studies. However these have poor external validity particularly for those at low or intermediate risk: a significant number of cardiovascular events still occurs in these groups. We hypothesised that screening for asymptomatic pre-clinical cardiovascular disease using B-type natriuretic peptide (BNP) and whole body contrast enhanced magnetic resonance imaging (MRI) could identify those at low/intermediate risk or disease whowill develop clinical disease and thus facilitate improved targeting of primary prevention at those most likely to benefit. The Tayside Screening for Cardiac Events (TASCFORCE) study is a prospective normal volunteer cohort study. Men and women aged 40 years or older free from cardiovascular disease and with a predicted 10-year coronary heart disease risk less than 20% were recruited. All had comprehensive baseline cardiovascular risk information and a BNP level measured. If the BNP level was greater than the median for their gender participants were invited to attend for a whole body contrast enhancedMRI scan comprising cardiac imaging and whole body angiography. The images were analysed to measure left ventricular mass (LVM), left ventricular volumes and left ventricular function. These were indexed for body size using height, height1.7, height2.7 and body surface area. Angiogram images were analysed for the presence and degree of intraluminal stenosis. All participants are being followed up using anonymised electronic data linkage for incident cardiovascular disease and death. 4423 participants (39.3% male) were recruited between November 2007 and February 2013. Median age was 51.2 years. The median 10-year coronary heart disease (CHD) 23 risk was 2% and 13.6% had a CHD risk of 10-19.9% (intermediate risk). The medianBNP results for men and women were 7.5 and 15.3 pg/ml respectively. Age, female sex and high density lipoprotein were independently associated with BNP level. Heart rate, total cholesterol and ex-smoking status were independently inversely associated with BNP level. 1528 (74.8% of those invited) underwent an MRI scan. Mean left ventricular mass was 129.2g and 87.0g for men and women respectively. LVM and left ventricular mass index (LVMI) were significantly higher in men than women. The vast majority (94.6%) of arterial segments analysed were normal and 50.6% of individuals had no evidence of luminal stenosis. From follow up data obtained 2 years after the end of recruitment 18,364 person years at risk were analysed. 17 cardiovascularevents and no deaths occurred in those not invited for an MRI scan based on their BNP result and 16 events and 1 death occurred in those invited for an MRI scan. There was no significant difference in event rates between those with above and below median BNP levels, between those with higher or lower LVM or LVMI or between those with and without the presence of stenosis on angiography. As expected we have not demonstrated the ability of LVM, LVMI or stenosis burden determined using magnetic resonance imaging to predict cardiovascular disease in a population at low or intermediate risk of CHD. We have also not demonstrated the ability of BNP to identify those at low orintermediate risk of CHD who will develop clinical CV disease. However it is the pre-planned longer-term follow up where difference might be expected. The low number of events at this early stage in follow up mean that it is difficult to draw firm conclusions. As follow up continues and further events accumulate we hope to determine if these measures will be shown to predict cardiovascular events in future analyses. We have characterised the normal values and distribution of a range of left ventricular structural and functional parameters derived using a steady state free precision sequence MRI in a population at low or intermediate risk of CHD which will provide a useful reference for normal values that are different to other imaging modalities including chocardiography and other protocols of MRI scanning.

Cardiovascular disease is a leading cause of morbidity and mortality globally. Early diagnostic markers are gaining popularity for better patient care disease outcomes. There is an increasing interest in noninvasive cardiac imaging biomarkers to diagnose subclinical cardiac disease. Feature tracking cardiac magnetic resonance imaging is a novel post-processing technique that is increasingly being employed to assess global and regional myocardial function. This technique has numerous applications in structural and functional diagnostics. It has been validated in multiple studies, although there is still a long way to go for it to become routine standard of care.

No description available.

No description available.

Beta-talassemia é uma das doenças genéticas mais comuns no mundo, com graus variados de anemia crônica, tratados por transfusões sanguíneas rotineiras nos casos mais graves. A sobrecarga de ferro acentuada a que esses pacientes são submetidos é a principal responsável pela morbimortalidade, sendo o acúmulo de ferro no miocárdio e a doença cardíaca disso decorrente, a principal causa de morte nessa população. A ressonância magnética cardíaca (RMC) é ferramenta central no acompanhamento desses pacientes, utilizando-se da técnica T2*, capaz de determinar a presença e grau da deposição de ferro no miocárdio, modificando o tratamento da terapia quelante de ferro (TQF). Além disso, outros parâmetros volumétricos e funcionais obtidos no exame de RMC podem estar alterados nesses pacientes. Até a atualidade, inexistem estudos nacionais descrevendo uma população de pacientes beta-talassêmicos pelos parâmetros da RMC. Objetivos: 1. Caracterizar a partir dos diversos parâmetros dos exames de RMC, a população dos pacientes talassêmicos acompanhados no Hospital das Clínicas da Faculdade de Medicina de Ribeirão Preto. 2. Avaliar o impacto dos diversos parâmetros da RMC com informações clinicas como mudança terapêutica, ocorrência de insuficiência cardíaca e óbito. Métodos: foram avaliados 44 pacientes com diagnóstico de beta-talassemia em seguimento no serviço de hematologia, para os quais foram solicitados exames de RMC na rotina clínica. Os exames incluíram sequências cine SSFP (steady state free precession) nos diversos planos cardíacos, incluindo uma sequência do eixo curto de ambos os ventrículos, esta utilizada para as medidas de volumes e função ventriculares. A sequência T2* utilizada foi gradiente eco com pré-pulso de saturação do sangue, com aquisição de 9 ecos consecutivos em apenas uma apneia. Sequência semelhante foi obtida para cálculo do T2* hepático. Foi feita revisão dos prontuários dos pacientes para avaliação dos dados clínicos. Resultados: 44 pacientes foram avaliados (25 do sexo masculino 56,8 %), com idade de 23,1±10,3 anos e diagnóstico de beta-talassemia maior em 30 casos (68,2 %) e talassemia intermedia em 14 casos (31,8 %). Foram descritos os volumes, massa e função para ambos os ventrículos, bem como a distribuição da medida do T2* miocárdico. Não foram observadas diferenças desses parâmetros entre os diferentes grupos de impregnação miocárdica pelo T2*. O seguimento médio do estudo foi de 4,0 (±1,1) anos com 4,7 (±1,6) exames por paciente. Foram identificados cinco pacientes com doença cardíaca e dois óbitos. Esses pacientes apresentaram redução significativa do T2* miocárdico, da fração de ejeção do ventrículo direito (VD), massa ventricular direita e esquerda e do volume sistólico final do VD, quando comparados aos indivíduos sem acometimento cardíaco reportado. Conclusão: Caracterizou-se a população de pacientes beta-talassêmicos acompanhados nesta instituição, em relação aos diversos parâmetros da RMC, salientando-se o impacto da introdução do método na mudança terapêutica. A medida do T2* miocárdico está correlacionada ao desenvolvimento de cardiopatia e pior evolução clínica, incluindo óbito. Acometimento do VD pode ser indicador precoce da impregnação miocárdica. / Beta-thalassemia is one of the most common genetic disorders worldwide, with different degrees of chronic anemia, treated with routine blood transfusions in severe cases. Morbidity and mortality is mainly related to the chronic iron overload and iron burden these patients endure. Myocardial iron overload and the development of cardiac disease remain the main cause of death for this population. Cardiac magnetic resonance (CMR) plays a central role in patient management, utilizing T2* sequences, which allows for detection and quantification of myocardial iron deposits, thus prompting changes in iron chelation therapy (ICT). Besides, there are other significant CMR volumetric and functional parameters to present abnormalities in these patients. To the present date, no national data has been published, describing a beta-thalassemia patient population from the standpoint of CMR parameters. Objectives: 1. To characterize, from the different CMR parameters, the beta-thalassemia patient population followed at a Brazilian tertiary hospital. 2. To evaluate the impact of these different CMR parameters, in relation to clinical data, such as therapeutic change, cardiac disease and death. Methods: 44 beta-thalassemia patients followed by the hematology service of this institution were evaluated, to whom CMR exams were performed in routine clinical practice. CMR exams included SSFP (steady state free precession) cine images through the different cardiac planes, including a short axis stack through both ventricles, used to calculate ventricular volumes and function. A gradient echo sequence with a dark blood pre-pulse saturation was used to calculate myocardial T2* values, with 9 consecutive echo times acquisition in one breath hold. A similar sequence was used to determine liver T2* values. Medical records were reviewed for clinical data. Results: 44 patients were evaluated (25 males, 56.8 %), with a mean age of 23,1 (±10,3) years, and diagnosis of betathalassemia major in 30 patients (68,2 %) and beta-thalassemia intermedia in 14 (31,8 %). Ventricular volumes, mass and function were described, as well as myocardial T2* distribution. There were no statistical difference observed among the different CMR parameters and the myocardial T2* degrees. Mean follow up was 4,0 (±1,1) years, with 4,7 (±1,6) exams per patient. Five patients with cardiac disease were identified with two deaths during observation. These patients showed a significantly reduced myocardial T2* and RVEF, and an elevated ventricular mass, for both ventricles, and final systolic right ventricular volume, when compared to patients without cardiac disease. Conclusion: A betathalassemia patient population was characterized through the different CMR parameters, highlighting the impact of CMR introduction to treatment decision. Myocardial T2* is related to cardiac disease development, clinical worsening and death. Right ventricular functional worsening could be an early sign of myocardial iron involvement.

No description available.

Background: This study aimed to evaluate the incremental prognostic value of infarct size, microvascular obstruction (MO), myocardial salvage index (MSI), and left ventricular ejection fraction (LV-EFCMR) assessed by cardiac magnetic resonance imaging (CMR) in comparison to traditional outcome markers in patients with ST-elevation myocardial infarction (STEMI) reperfused by primary percutaneous intervention (PCI). Methods: STEMI patients reperfused by primary PCI (n = 278) within 12 hours after symptom onset underwent CMR three days after the index event (interquartile range [IQR] two to four). Infarct size and MO were measured 15 minutes after gadolinium injection. T2-weighted and contrast-enhanced CMR were used to calculate MSI. In addition, traditional outcome markers such as ST-segment resolution, pre- and post-PCI Thrombolysis In Myocardial Infarction (TIMI)-flow, maximum level of creatine kinase-MB, TIMI-risk score, and left ventricular ejection fraction assessed by echocardiography were determined in all patients. Clinical follow-up was conducted after 19 months (IQR 10 to 27). The primary endpoint was defined as a composite of death, myocardial reinfarction, and congestive heart failure (MACE). Results: In multivariable Cox regression analysis, adjusting for all traditional outcome parameters significantly associated with the primary endpoint in univariable analysis, MSI was identified as an independent predictor for the occurrence of MACE (Hazard ratio 0.94, 95% CI 0.92 to 0.96, P <0.001). Further, C-statistics comparing a model including only traditional outcome markers to a model including CMR parameters on top of traditional outcome markers revealed an incremental prognostic value of CMR parameters (0.74 versus 0.94, P <0.001). Conclusions: CMR parameters such as infarct size, MO, MSI, and LV-EFCMR add incremental prognostic value above traditional outcome markers alone in acute reperfused STEMI.

Obesity is a major epidemic and is increasing in prevalence worldwide. The health problems and consequences of obesity include cardiovascular disease (CVD) risk factors, such as hypertension, hyperlipidemia, glucose intolerance and diabetes mellitus. Each of these abnormalities directly promotes atherosclerosis. More recently, visceral obesity has been shown to be independently associated with abnormalities of both the ventricular and vascular structure and function. The mechanisms by which they occur remain incompletely defined. Cardiovascular magnetic resonance imaging (CMR) offers several advantages for evaluation of cardiac structure and function in the obese. The high accuracy and reproducibility of the technique allows for detection of very small changes in ventricular volumes, mass, ejection fraction, and cardiac output with a relatively small sample size, as compared with echocardiography. In this thesis we investigated whether cardiovascular magnetic resonance imaging can better characterize possible cardiac abnormalities associated with obesity, in the absence of other confounding comorbidities. Obesity is associated with myocardial and vascular function, the extent of reversibility of these abnormalities with rapid acute weight loss remains uncertain. Therefore the first aim of the study was to (i) determine the relationship between obesity and left ventricular structure and function using magnetic resonance imaging, and (ii) the acute effects of rapid diet-induced weight loss on cardiac and vascular function in normal obese and obese diabetic men. Erectile dysfunction is related to cardiovascular risk factors such as obesity by an impairment of endothelial function. Therefore, symptoms of erectile dysfunction are probably to precede cardiovascular disease and events. The second aim of this study was to (i) determine the relationship between obesity and erectile function (EF), sexual desire (SD), lower urinary tract symptoms (LUTS) and quality of life (QOL) measures in obese males, and (ii) determine the effects of rapid diet-induced weight loss on EF, SD, LUTS and QOL measures in normal obese and obese diabetic men. In this group of men, obesity was associated with mild/moderate erectile dysfunction, and significant LUTS, which together with sexual desire improved following rapid diet induced weight loss, but was not directly related to the amount of weight loss or changes in measured metabolic state. Pericardial adipose tissue (PAT) covers 80% of the heart and constitutes 20% of its weight. PAT mass is related to the amount of abdominal fat and the risk of coronary atherosclerosis. Epicardial fat mass may be a sensitive indicator of cardiovascular risk. The third aim of this study was to (i) determine the relationship between obesity and PAT volume and (ii) effectively evaluate the impact of caloric restriction and associated weight reduction on epicardical fat volume via cardiac magnetic resonance imaging (CMR). This is the first study to show a reduction in PAT volume is associated with caloric restriction. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1352389 / Thesis (Ph.D.) - University of Adelaide, School of Medicine, 2009

Obesity is a major epidemic and is increasing in prevalence worldwide. The health problems and consequences of obesity include cardiovascular disease (CVD) risk factors, such as hypertension, hyperlipidemia, glucose intolerance and diabetes mellitus. Each of these abnormalities directly promotes atherosclerosis. More recently, visceral obesity has been shown to be independently associated with abnormalities of both the ventricular and vascular structure and function. The mechanisms by which they occur remain incompletely defined. Cardiovascular magnetic resonance imaging (CMR) offers several advantages for evaluation of cardiac structure and function in the obese. The high accuracy and reproducibility of the technique allows for detection of very small changes in ventricular volumes, mass, ejection fraction, and cardiac output with a relatively small sample size, as compared with echocardiography. In this thesis we investigated whether cardiovascular magnetic resonance imaging can better characterize possible cardiac abnormalities associated with obesity, in the absence of other confounding comorbidities. Obesity is associated with myocardial and vascular function, the extent of reversibility of these abnormalities with rapid acute weight loss remains uncertain. Therefore the first aim of the study was to (i) determine the relationship between obesity and left ventricular structure and function using magnetic resonance imaging, and (ii) the acute effects of rapid diet-induced weight loss on cardiac and vascular function in normal obese and obese diabetic men. Erectile dysfunction is related to cardiovascular risk factors such as obesity by an impairment of endothelial function. Therefore, symptoms of erectile dysfunction are probably to precede cardiovascular disease and events. The second aim of this study was to (i) determine the relationship between obesity and erectile function (EF), sexual desire (SD), lower urinary tract symptoms (LUTS) and quality of life (QOL) measures in obese males, and (ii) determine the effects of rapid diet-induced weight loss on EF, SD, LUTS and QOL measures in normal obese and obese diabetic men. In this group of men, obesity was associated with mild/moderate erectile dysfunction, and significant LUTS, which together with sexual desire improved following rapid diet induced weight loss, but was not directly related to the amount of weight loss or changes in measured metabolic state. Pericardial adipose tissue (PAT) covers 80% of the heart and constitutes 20% of its weight. PAT mass is related to the amount of abdominal fat and the risk of coronary atherosclerosis. Epicardial fat mass may be a sensitive indicator of cardiovascular risk. The third aim of this study was to (i) determine the relationship between obesity and PAT volume and (ii) effectively evaluate the impact of caloric restriction and associated weight reduction on epicardical fat volume via cardiac magnetic resonance imaging (CMR). This is the first study to show a reduction in PAT volume is associated with caloric restriction. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1352389 / Thesis (Ph.D.) - University of Adelaide, School of Medicine, 2009