Magnetic Resonance Imaging Of Heart Research Articles

Excess of high-caffeinated energy drinks causing ventricular arrhythmias

ABSTRACT A young male patient had palpitations after consumption of few high caffeinated energy drinks which he took after his office hours to relieve fatigue. He immediately seeked medical help. Electrocardiogram showed multiple runs of non-sustained ventricular tachycardia and ventricular bigeminy and trigeminy. Echocardiography was normal. The patient was admitted to intensive care unit and treated with anti-arrhythmic drugs to which the arrhythmias responded and subsided. Cardiac magnetic resonance imaging of heart did not reveal any structural heart abnormality and treadmill stress test was negative ruling out significant coronary artery disease. High caffeinated energy drinks can produce serious ventricular arrhythmias if taken beyond safe doses. These ventricular arrhythmias are known to be causative factor for sudden cardiac arrest and therefore a caution & regulation is needed in widespread unrestricted used of these drinks.

Use of Deferasirox Film-Coated Tablets in Pediatric Patients with Transfusion Dependent Thalassemia: A Single Center Experience.

Simple SummaryThalassemia is a hereditary anemia characterized by defect in hemoglobin synthesis. Patients with severe forms of the disease require regular blood transfusions, as well as iron chelation. Available chelators have demonstrated long-term efficacy and safety, but present various limitations. A new deferasirox film-coated tablet (DFX FCT) was designed to offer a more convenient mode of administration and better tolerability. The present study aimed to assess the efficacy and safety of DFX FCT in thalassemic pediatric patients. DFX FCT proved safe for older patients, but demonstrated increased frequency of adverse events in younger patients, resulting in drug discontinuation. As for efficacy, DFX FCT succeeded in maintaining a stable iron load, though it required use of relatively high doses.Thalassemic syndromes are characterized by clinical heterogenicity. For severe disease forms, lifelong blood transfusions remain the mainstay of therapy, while iron overload monitoring and adequate chelation treatment are required in order to ensure effective disease management. Compared to previous chelators, the new deferasirox film-coated tablet (DFX FCT) is considered to offer a more convenient and well-tolerated treatment scheme, aiming at better treatment-related and patient-related outcomes. The present study’s objective was to prospectively evaluate the safety and efficacy of DFX FCT in children and adolescents with transfusion-dependent thalassemia. Data collected included patient demographics, hematology and biochemistry laboratory work up, magnetic resonance imaging of heart and liver for iron load, as well as ophthalmological and audiological examination prior to and a year following drug administration. Study results confirmed DFX FCT safety in older children in a manner similar to adults, but demonstrated increased frequency of adverse events in younger patients, mainly, involving liver function. With regards to efficacy, study results confirmed the preventive role of DFX FCT in iron loading of liver and heart, however, higher doses than generally recommended were required in order to ensure adequate chelation.

4D FLOW Magnetic Resonance Imaging in the Study of Blood Flow in Patients With Aortic Coarctation in the Long-Term After Surgery

Aim Comprehensive evaluation of blood flow in the thoracic aorta using a software for 4D processing of magnetic resonance (MR) images of the heart and blood vessels (4D Flow) in patients with aortic coarctation in the late postoperative period.Materials and methods The MR study of the heart was performed for 10 patients (7 boys and 3 girls) aged 8 to 13 years (median, 9.5 [8.3; 10.8] years) who underwent resection with end-to-end anastomosis for aortic coarctation at age of 2 weeks to 10 months. MR tomography was performed on a 1.5 T MR scanner using a multichannel surface coil for scanning, electrocardiographic synchronization, and a specialized package of pulse sequences for scanning of the heart. Blood flow was evaluated with a 4D data handling software for processing of MR images of heart and blood vessels (4D Flow). The following blood flow parameters were analyzed: blood flow volume per second, peak blood flow velocity, peak and minimum blood flow area at the levels of ascending aorta, arch, isthmus, and descending aorta, and pressure gradient at the level of maximum narrowing of the aorta. 3D-MR images were used for evaluation of aortic geometry. Blood flow formation, distribution, and trajectories were analyzed by maps of vectors, particle trace, and stream lines. Statistical analysis was performed with a Statistica (v. 6.0 StatSoft Inc.) package.Results Accelerated flow in the region of residual aortic stenosis in systole was observed in all patients; 4 patients had an additional vortex flow below the aortic stenosis and a spiral flow in the descending aorta. The pressure gradient on the aortic isthmus was directly correlated with the left ventricular myocardial mass index (r=0.65; р=0.04) and indexes of blood flow in the ascending and descending aorta (р=0.03; р=0.026). No significant correlation was found for blood flow indexes and geometry of the aortic arch (H / L). Delayed contrast enhancement MR imaging did not detect any fibrotic changes in the myocardium in only one patient. The fibrosis severity inversely correlated with the right ventricular ejection fraction (r=0.65; р=0.04) and directly correlated with the pressure gradient at the aortic isthmus (r=0.63; p=0.05).Conclusion The 4D MR image processing software for the heart and blood vessels allows studying the blood flow in detail under natural conditions, provides potential advantages in comprehensive evaluation of patients with aortic coarctation during a dynamic follow-up. For a definitive conclusion about the relationship between the altered blood flow in the thoracic aorta and markers of residual, post-correction pathology, larger studies are required as well as long-term follow-up of patients with documented pathological patterns of blood flow (changes in blood flow velocity and volume throughout the entire thoracic aorta in combination with disorders in the normal flow geometry during the cardiac cycle).

Optimal preservation of porcine cardiac tissue prior to diffusion tensor magnetic resonance imaging.

The effects of ex vivo preservation techniques on the quality of diffusion tensor magnetic resonance imaging in hearts are poorly understood, and the optimal handling procedure prior to investigation remains to be determined. Therefore, 24 porcine hearts were examined in six groups treated with different preservation techniques, including chemical fixation and freezing. Diffusion properties of each heart were assessed with diffusion tensor imaging in terms of fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (Da) and radial diffusivity (Dr). Tractography was performed to visualize the course of the cardiomyocytes, assuming greater diffusivity in the longitudinal than the transverse axis of individual cardiomyocytes. Significant differences in MD, Da and Dr were found, as well as in FA between groups (P < 0.001). Freezing of specimens resulted in the lowest mean FA of 0.21 (0.06) and highest Dr of 8.92 (1.5) mm2 s(-1) . The highest mean FA was found to be 0.43 (0.11) in hearts perfusion-fixed with formalin. Calculated tractographies were indistinguishable among groups except in frozen specimens, where no fibres could be tracked. Perfusion fixation with formalin provided the best tractography, but immersion fixation yielded diffusion data most similar to fresh hearts. These findings suggest that parameters derived from diffusion tensor imaging in ex vivo hearts are sensitive to fixation and storage methods. In particular, freezing of specimens should be avoided prior to diffusion tensor imaging investigation due to significant changes in diffusion parameters and subsequent image deteriorations.

Endocrinopathies, metabolic disorders, and iron overload in major and intermedia thalassemia: serum ferritin as diagnostic and predictive marker associated with liver and cardiac T2* MRI assessment.

Endocrinopathies and metabolic disorders-characterized β thalassemic (βT) patients and the prevention and treatment of these comorbidities are important targets to be achieved. The aim of the study was to analyze the diagnostic and prognostic role of ferritin for endocrinopathies and metabolic disorders in βT patients. The ability of iron chelators to treat iron overload and to prevent or reverse metabolic disorders and endocrinopathies was also evaluated. Seventy-two βT patients were treated with different chelation strategies during the study. Receiver operating characteristics analysis was employed to calculate the area under the curve for serum ferritin to find the best cutoff values capable of identifying endocrine dysfunction in thalassemic patients. Kaplan-Meier curves were generated to assess the incidence of endocrinopathy. Adjusted risk estimates for endocrinopathy were calculated using univariate followed by multivariate Cox proportional hazard regression analysis. High ferritin levels were observed in patients with hypothyroidism [1500 (872.5-2336.5) μg/L], hypogonadism [878 (334-2010) μg/L], and in patients with hypoparathyroidism or osteoporosis [834 (367-1857) μg/L]. A strict correlation between ferritin and T2* magnetic resonance imaging of heart (r = -0.64; P:0.0006) and liver (r = -0.40; P:0.03) values was observed. Patients with ferritin values above 1800 μg/L experienced a significantly faster evolution to hypothyroidism [log-rank (χ(2) ):7.7; P = 0.005], hypogonadism [log-rank (χ(2) ):10.7; P = 0.001], and multiple endocrinopathies [log-rank (χ(2) ):5.72; P = 0.02]. Ferritin predicted high risk of endocrine dysfunction independently of confounding factors (HR:1.23; P < 0.0001). The intensification of chelation therapy led to an amelioration of hypothyroidism. Ferritin represents a prognostic marker for βT patients and a predictive factor for progression to endocrine dysfunctions. Intensive chelation therapy allows the reversibility of hypothyroidism.

Harmonic phase interference for the detection of tag line crossings and beyond in homogeneous strain analysis of cardiac tagged MRI data

Homogenous strain analysis (HSA) was developed to evaluate regional cardiac function using tagged cine magnetic resonance images of heart. Current cardiac applications of HSA are however limited in accurately detecting tag intersections within the myocardial wall, producing consistent triangulation of tag cells throughout the image series and achieving optimal spatial resolution due to the large size of the triangles. To address these issues, this article introduces a harmonic phase (HARP) interference method. In principle, as in the standard HARP analysis, the method uses harmonic phases associated with the two of the four fundamental peaks in the spectrum of a tagged image. However, the phase associated with each peak is wrapped when estimated digitally. This article shows that special combination of wrapped phases results in an image with unique intensity pattern that can be exploited to automatically detect tag intersections and to produce reliable triangulation with regularly organized partitioning of the mesh for HSA. In addition, the method offers new opportunities and freedom for evaluating myocardial function when the power and angle of the complex filtered spectra are mathematically modified prior to computing the phase. For example, the triangular elements can be shifted spatially by changing the angle and/or their sizes can be reduced by changing the power. Interference patterns obtained under a variety of power and angle conditions were presented and specific features observed in the results were explained. Together, the advanced processing capabilities increase the power of HSA by making the analysis less prone to errors from human interactions. It also allows strain measurements at higher spatial resolution and multi-scale, thereby improving the display methods for better interpretation of the analysis results.

Using inverse electrocardiography to image myocardial infarction—reflecting on the 2007 PhysioNet/Computers in Cardiology Challenge

The goal of the 2007 PhysioNet/Computers in Cardiology Challenge was to try to establish how well it is possible to characterize the location and extent of old myocardial infarcts using electrocardiographic evidence supplemented by anatomical imaging information. A brief overview of the challenge and how different challengers approached the competition is provided, followed by detailed response of the first author to integrate electrophysiologic and anatomical data. The first author used the provided 120-electrode body-surface potential mapping data and magnetic resonance imaging heart and torso images to calculate epicardial potentials on customized ventricular geometries. A method was developed to define the location and extent of scar tissue based on the morphology of computed epicardial electrograms. Negative Q-wave deflection followed by R-wave on the left ventricular surface seemed to correspond with the location of the scar as determined by the gadolinium-enhanced magnetic resonance imaging gold standard in the supplied data sets. The method shows promising results as a noninvasive imaging tool to quantitatively characterize chronic infarcts and warrants further investigation on a larger patient data set.

Distribution of intracellular, extracellular, and intravascular contrast media for magnetic resonance imaging in hearts subjected to reperfused myocardial infarction

Distribution of intracellular, extracellular, and intravascular contrast media for magnetic resonance imaging in hearts subjected to reperfused myocardial infarction

Determination of left ventricular mass by magnetic resonance imaging in hearts deformed by acute infarction.

Measurement of left ventricular (LV) mass by magnetic resonance imaging (MRI) is accurate in normal hearts. Because determination of mass by MRI does not require assumptions about ventricular shape, this method may be well suited for evaluating hearts distorted by infarction. To test this hypothesis, gated MRI was performed in 15 dogs before and after acute myocardial infarction. The LV mass of each dog was calculated from five short-axis images acquired at end systole, when shape distortion is greatest, at end diastole, and also from slices at varying phases of the cycle with a multiphase mode that required only one acquisition. Correlation was excellent between actual mass and end-systolic mass before infarction (p less than 0.001, r = 0.98, and SEE = 5.1 g) and after infarction (p less than 0.001, r = 0.97, and SEE = 6.6 g). Likewise, values correlated closely at end diastole before (p less than 0.001, r = 0.96, and SEE = 6.7 g) and after infarction (p less than 0.001, r = 0.94, and SEE = 8.7 g). Surprisingly, measurements of mass by a multiphase mode were also very accurate before (p less than 0.001, r = 0.98, and SEE = 5.1 g) and after (p less than 0.001, r = 0.95, and SEE = 6.49 g) infarction. Therefore, at the same phase and at multiphases of the cardiac cycle, MRI permits accurate determination of LV mass in distorted hearts.