scholarly journals Efficient compressed sensing reconstruction frameworks for accelerated cardiac magnetic resonance imaging

2021 ◽  
Author(s):  
Azar Tolouee
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Compressed Sensing ◽  
Motion Estimation ◽  
Cardiac Mri ◽  
Respiratory Motion ◽  
Dynamic Mri ◽  
Resonance Imaging ◽  
Frame Motion ◽  
Inter Frame

Dynamic magnetic resonance imaging requires rapid data acquisition to provide an appropriate combination of spatial and temporal resolution, and volumetric coverage for clinical studies. In the most challenging clinical situations, conventional dynamic MR scanners are often incapable of simultaneously providing images with sufficient temporal resolution and high spatial resolution. In practice, clinicians are often forced to compromise between these parameters, often resulting in sub-optimal performance. Cardiac MRI is the most challenging and inspiring dynamic MRI application. In cardiac MRI, the main challenge is the sensitivity of reconstruction methods to large inter frame motion. The reconstructions often suffer from temporal blurring and motion related artifacts at high acceleration factors. In this dissertation, three novel approaches are proposed specifically designed to minimize the sensitivity of the reconstructions to inter frame motion. First, a compressed sensing (CS) based image reconstruction method in conjunction with spiral sampling is developed for the reconstruction of dynamic MRI data from highly accelerated / under-sampled Fourier measurements. In the second algorithm, the problem of motion artifacts including respiratory motion and cardiac motion in compressed sensing reconstructions is addressed. A motion estimation/motion compensation algorithm based on a modified search that aids block matching and results in improved residual reconstruction is incorporated into the CS reconstruction for dynamic MRI. In the third algorithm, a novel formulation for the joint estimation of the deformation and the dynamic images in cardiac cine MR imaging is introduced. The motion estimation algorithm estimates the deformation by registering the dynamic data to a reference dataset that is free of respiratory motion, which is derived from the measurements themselves. A variable splitting framework is used to minimize the objective function, and thus derive the deformation and the dynamic images. The validation of the proposed algorithms is illustrated using a numerical phantom and in-vivo cine MRI data to show the feasibility in precisely recovering cardiac MRI data from extensively under-sampled data.

scholarly journals Efficient compressed sensing reconstruction frameworks for accelerated cardiac magnetic resonance imaging

2021 ◽  
Author(s):  
Azar Tolouee
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Compressed Sensing ◽  
Motion Estimation ◽  
Cardiac Mri ◽  
Respiratory Motion ◽  
Dynamic Mri ◽  
Resonance Imaging ◽  
Frame Motion ◽  
Inter Frame

Dynamic magnetic resonance imaging requires rapid data acquisition to provide an appropriate combination of spatial and temporal resolution, and volumetric coverage for clinical studies. In the most challenging clinical situations, conventional dynamic MR scanners are often incapable of simultaneously providing images with sufficient temporal resolution and high spatial resolution. In practice, clinicians are often forced to compromise between these parameters, often resulting in sub-optimal performance. Cardiac MRI is the most challenging and inspiring dynamic MRI application. In cardiac MRI, the main challenge is the sensitivity of reconstruction methods to large inter frame motion. The reconstructions often suffer from temporal blurring and motion related artifacts at high acceleration factors. In this dissertation, three novel approaches are proposed specifically designed to minimize the sensitivity of the reconstructions to inter frame motion. First, a compressed sensing (CS) based image reconstruction method in conjunction with spiral sampling is developed for the reconstruction of dynamic MRI data from highly accelerated / under-sampled Fourier measurements. In the second algorithm, the problem of motion artifacts including respiratory motion and cardiac motion in compressed sensing reconstructions is addressed. A motion estimation/motion compensation algorithm based on a modified search that aids block matching and results in improved residual reconstruction is incorporated into the CS reconstruction for dynamic MRI. In the third algorithm, a novel formulation for the joint estimation of the deformation and the dynamic images in cardiac cine MR imaging is introduced. The motion estimation algorithm estimates the deformation by registering the dynamic data to a reference dataset that is free of respiratory motion, which is derived from the measurements themselves. A variable splitting framework is used to minimize the objective function, and thus derive the deformation and the dynamic images. The validation of the proposed algorithms is illustrated using a numerical phantom and in-vivo cine MRI data to show the feasibility in precisely recovering cardiac MRI data from extensively under-sampled data.

scholarly journals Follow-up magnetic resonance imaging of Löffler endocarditis: a case report

2020 ◽  
Author(s):  
Shinya Ito ◽  
Akihiro Isotani ◽  
Kyohei Yamaji ◽  
Kenji Ando
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Corticosteroid Therapy ◽  
Cardiac Mri ◽  
High Intensity ◽  
Left Ventricular ◽  
Eosinophil Infiltration ◽  
Resonance Imaging ◽  
T2 Weighted Images

Abstract Background  Löffler endocarditis is a condition characterized by cardiac infiltration of eosinophils. Cardiac magnetic resonance imaging (MRI) is a modality for the diagnosis of myocardial damage. Case summary  This is the case of a 77-year-old man with acute decompensated heart failure who was admitted. Transthoracic echocardiography showed preserved left ventricular (LV) systolic function along with LV thrombi attached to the septo-apical wall and the posterior wall, consistent with Löffler endocarditis. Cardiac MRI revealed obliteration of the LV apex and partial filling of the LV cavity, as well as near circumferential subendocardial late gadolinium enhancement (LGE) in the mid- and apical segments. T2-weighted images showed a near circumferential high-intensity area of the LV subendocardial muscle in the mid- and apical segments. High-dose corticosteroids and intravenous heparin were initiated, followed by maintenance warfarin therapy. At 18 months, follow-up cardiac MRI revealed the disappearance of the LV thrombi, and a reduction of LGE, as well as high-intensity areas in the T2-weighted images. Discussion  The high-intensity area of T2-weighted images indicate the presence of subendocardial oedema. Eosinophil-mediated heart damage evolves through three stages: (i) acute necrotic, (ii) thrombotic, and (iii) fibrotic stages. Since the deposition of toxic eosinophil granule proteins and eosinophil infiltration injured the endocardium, the first-line treatment for Löffler endocarditis is corticosteroid therapy. In this case, LGE in the subendocardium and the high-intensity area in the T2-weighted images were reduced at 18 months. High-intensity areas of T2-weighted images in the acute phase might indicate the possibility of therapeutic response to corticosteroid therapy.

scholarly journals An Augmented Lagrangian Based Compressed Sensing Reconstruction for Non-Cartesian Magnetic Resonance Imaging without Gridding and Regridding at Every Iteration

PLoS ONE ◽  
2014 ◽  
Vol 9 (9) ◽  
pp. e107107 ◽  
Author(s):  
Mehmet Akçakaya ◽  
Seunghoon Nam ◽  
Tamer A. Basha ◽  
Keigo Kawaji ◽  
Vahid Tarokh ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Compressed Sensing ◽  
Augmented Lagrangian ◽  
Resonance Imaging

scholarly journals Correlation between Echocardiography and MRI in Volumetric Analysis of Dilated Cardiomyopathy - A Cross-Sectional Study from Puttaparthi, Andhra Pradesh

2021 ◽  
Vol 8 (19) ◽  
pp. 1391-1396
Author(s):  
Kushal Singh ◽  
Anshita Singh ◽  
Piyush Piyush
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Stroke Volume ◽  
Dilated Cardiomyopathy ◽  
Cardiac Mri ◽  
Andhra Pradesh ◽  
Cross Sectional Study ◽  
Sectional Study ◽  
Resonance Imaging ◽  
Cross Sectional

BACKGROUND Echocardiography is considered as a traditional approach to clinically study dilated cardiomyopathy. Because of poor apical visibility, however, volumetric calculations are difficult to ascertain. In calculating left ventricle volumes and ejection fractions, magnetic resonance (MR) imaging has shown to be more accurate than echocardiography. Due to conflicting literature, the present study was conducted to diagnose dilated cardiomyopathy using 2 D - echocardiography and correlate these echocardiographic findings with magnetic resonance imaging (MRI). METHODS This observational cross-sectional study was conducted in the Department of Radio-diagnosis and Imaging, Sri Sathya Sai Institute of Higher Medical sciences, Puttaparthi, Andhra Pradesh, Pin 515134. The study group consisted of consecutive patients who had clinical suspicion of dilated cardiomyopathy. A total of 40 patients underwent both 2 D - echo and cardiac MRI on the same day. All patients underwent 2 - D echo which was performed at the frame rate of 40 - 80 frames per second in the left lateral decubitus position to obtain standard 2, 3, and 4 chambers as well as short axis views (GE Vingmed Vivid 7 Dimensions, Horton, Norway: 2.5 MHz transducer). MRI was performed on a 1.5 T scanner (Mangnetom Aera, Siemens, Erlangen, Germany). For patient monitoring and cardiac synchronization, 3 - lead electrocardiography was used. RESULTS In the present study, in comparison to reference standard (cardiac MRI), 2 D - echocardiography showed significant and systematic underestimation of enddiastolic volume (EDV), end-systolic volume (ESV) and stroke volume (SV). Good correlation between 2 D - echo and cardiac MRI was noted for end-diastolic volume (r = 0.89), stroke volume (r = 0.60) and ejection fraction (r = 0.75). CONCLUSIONS In summary, magnetic resonance imaging is an accurate, non-invasive, safe and advanced modality for evaluation of global left ventricular function and myocardial scarring. 2 D - echocardiography can be used for screening of the patients with clinically suspected dilated cardiac myopathy (DCM) and their follow up. KEYWORDS Echocardiography, MRI, Cardiomyopathy

scholarly journals Heart arrhythmias and conduction disorders in patients with acromegaly: the role of cardiac magnetic resonance imaging

2020 ◽  
Vol 92 (10) ◽  
pp. 70-77
Author(s):  
K. V. Melkozerov ◽  
E. G. Przhiyalkovskaya ◽  
N. V. Tarbaeva ◽  
A. A. Almaskhanova ◽  
M. D. Kuklina ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Myocardial Fibrosis ◽  
Cardiac Mri ◽  
Somatostatin Analogs ◽  
Cardiac Conduction ◽  
Resonance Imaging ◽  
Functional Changes ◽  
Conduction Disorders

Cardiovascular complications including arrhythmias and cardiac conduction disorders are one of the main reasons of high mortality rate in acromegaly, while they have not been well explored. Aim.To estimate arrhythmias frequency in acromegaly, identify risk factors leading to the development of arrhythmia and cardiac conduction disorder, to determine the role of cardiac MRI in detecting structural and functional changes. Materials and methods.A single-center prospective cohort study, which included 461 patients (151 men and 310 women) with acromegaly, was conducted. All the patients underwent a standard medical examination, including hormonal blood test, electrocardiogram, echocardiography, electrocardiogram daily monitoring. 18 patients with arrhythmias (11 men and 7 women) had cardiac MRI with gadolinium-based contrast. Results.The results of our research show high frequency of arrhythmias and cardiac conduction disorders in patients with acromegaly 42%. Most frequent kinds of arrhythmias and cardiac conduction disorders were sinus bradycardia 19.1% of the cases and conduction disorders of bundle branch blocks 14.5%. Men were more likely to suffer from arrhythmias and cardiac conduction disorders than women (54.2% and 37.4%, respectively,p=0.0005). Not acromegaly activity but duration of the disease was a main risk factor of arrhythmias and cardiac conduction disorders. Patients with arrhythmias had a long anamnesis of acromegaly (10 and 7 years, respectively, p=0.04). Meanwhile, cardiac conduction disorders were commonly observed in the patients who were treated with somatostatin analogs comparing to the patients who didnt undergo this therapy (50% and 38.6% respectively,p=0.004). We showed that 61% of patients with acromegaly and cardiac conduction disorders who underwent magnetic resonance imaging (MRI) had the signs of myocardial fibrosis. The value of the ejection fraction of the left ventricle according to MRI was higher than with echocardiography (p=0.04). Conclusion.Arrhythmias and cardiac conduction disorders are often observed in patients with acromegaly even with remission of the disease. High risk group need careful diagnostic and monitoring approaches. Cardiac MRI is the gold standard for visualization of structural and morphological changes in the heart. Use of cardiac MRI in acromegalic patients expands our understanding of arrhythmias and cardiac conduction disorders in this disease. There are no specific laboratory markers of diffuse myocardial fibrosis, and the role of myocardial fibrosis in the occurrence of cardiac arrhythmias and conduction disorders needs further studying.

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