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Background: Diffuse myocardial fibrosis may provide a substrate for the initiation and maintenance of ventricular arrhythmia. T1 mapping overcomes the limitations of the conventional delayed contrast-enhanced cardiac magnetic resonance (CE-CMR) imaging technique by allowing quantification of diffuse fibrosis.Objective: The purpose of this study was to assess whether myocardial tissue characterization using T1 mapping would predict ventricular arrhythmia in ischemic and non-ischemic cardiomyopathies.Methods: This was a prospective longitudinal study of consecutive patients receiving implantable cardioverter-defibrillators in a tertiary cardiac center. Participants underwent CMR myocardial tissue characterization using T1 mapping and conventional CE-CMR scar assessment before device implantation. The primary end point was an appropriate implantable cardioverter-defibrillator therapy or documented sustained ventricular arrhythmia.Results: One hundred thirty patients (71 ischemic and 59 non-ischemic) were included with a mean follow-up period of 430 ± 185 days (median 425 days; interquartile range 293 days). At follow-up, 23 patients (18%) experienced the primary end point. In multivariable-adjusted analyses, the following factors showed a significant association with the primary end point: secondary prevention (hazard ratio [HR] 1.70; 95% confidence interval [95% CI] 1.01-1.91), noncontrast T1(_native) for every 10-ms increment in value (HR 1.10; CI 1.04-1.16; 90-ms difference between the end point-positive and end point-negative groups), and Grayzone(_2sd-3sd) for every 1% left ventricular increment in value (HR 1.36; CI 1.15-1.61; 4% difference between the end point-positive and end point-negative groups). Other CE-CMR indices including Scar(_2sd), Scar(_FWHM), and Grayzone(_2sd-FWHM) were also significantly, even though less strongly, associated with the primary end point as compared with Grayzone(_2sd-3sd).Conclusion: Quantitative myocardial tissue assessment using T1 mapping is an independent predictor of ventricular arrhythmia in both ischemic and non-ischemic cardiomyopathies. [ABSTRACT FROM AUTHOR]

Abstract Quantification and imaging of magnetic nanoparticles is of vital importance for various novel biomedical applications, like cell tracking, drug targeting or hyperthermia treatments. In this work we studied the performance of magnetic resonance imaging (MRI) and magnetic particle imaging (MPI) for quantitative imaging of magnetic nanoparticles (MNP). This was done by measurements of serial dilutions of MNP (Ferucarbotran) in two different media (water and CuSO 4 solution). The concentration range in which quantification was possible was determined for each technique, and the influence of the environment was analyzed and discussed. This revealed a significantly stronger influence of the surrounding medium on MRI performance as compared to MPI. All results were validated by measurements using their respective zero-dimensional (spectroscopic) techniques nuclear magnetic resonance and magnetic particle spectroscopy, showing similar behavior compared to the imaging modalities. Physical explanations of all observed effects are given, and a concentration range is determined in which the advantages of both imaging techniques can be utilized. [ABSTRACT FROM AUTHOR]