Simulation, design, and test of an elliptical surface coil for magnetic resonance imaging and spectroscopy

AbstractThe simplest design of surface coils for magnetic resonance imaging (MRI) applications is circular and square loops, both producing a magnetic field perpendicular to the coil plane in the central region‐of‐interest (ROI), with an amplitude that decreases along the coil axis. However, a surface coil constituted by a loop with different geometry could be necessary when particular field‐of‐views (FOVs) are desired, especially for performing imaging in an elongated region. This can be achieved by using an elliptical loop, which can guarantee a wide longitudinal FOV and a good penetration in deep sample regions. This work proposes the application of a method for elliptical coil Signal‐to‐Noise Ratio (SNR) estimation previously developed for circular and square loop design, in which coil inductance and resistance are analytically calculated and the magnetic field pattern is estimated using the magnetostatic approach, while the sample‐induced resistance is calculated with the vector potential calculation method. In the second part of the paper, we propose the simulation and the design of a transmit/receive elliptical coil for MRI in mice with a 3T clinical scanner. We also evaluated the coil performance in a preliminary magnetic resonance spectroscopy (MRS) study in phantom

Cardiovascular magnetic resonance imaging in hypertrophic cardiomyopathy:the importance of clinical context

In patients with suspected or established hypertrophic cardiomyopathy (HCM), cardiovascular magnetic resonance (CMR) is widely employed for clinical management, given its multimodality approach capable of providing unique information on cardiac morphology, function, and tissue characterization. Guidance regarding all aspects of HCM diagnosis and management is provided by the comprehensive 2014 European Society of Cardiology (ESC) guidelines on HCM. CMR should be performed in centres with recognized expertise in heart muscle diseases, by physicians who are familiar with the whole HCM disease spectrum, differential diagnoses, and pitfalls. Because CMR is usually performed and interpreted by physicians not directly involved in patient care, detailed, bidirectional, and standardized communication becomes essential to obtain best results and avoid misinterpretation. In order to maximize the potential of CMR, it is of paramount importance that reporting physicians are provided with the essential clinical information and that, in turn, referring physicians are given a core set of CMR morphological, functional, and tissue characterization results following the test. This article aims to summarize the current knowledge on the role of CMR in managing HCM and, in addition, to review the importance of the clinical context in which the report is provided, in both adult and paediatric population, highlighting implications for clinical research

Implications of atrial volumes in surgical corrected Tetralogy of Fallot on clinical adverse events

Background: While left atrial (LA) size has been shown as a strong predictor of cardiovascular diseases in various studies, the role of right atrial (RA) enlargement, especially in the growing population of patients with congenital heart diseases (CHD) is largely unknown. We sought to evaluate (1) RA and LA volumes in patients with repaired Tetralogy of Fallot (TOF) and assess correlations to (2) functional parameters and (3) clinical adverse events. Methods: 169 patients with repaired TOF were enrolled following a targeted protocol for Cardiovascular magnetic resonance imaging (CMR), Cardiopulmonary exercise tests (CPET), Echocardiography and Measurement of NT-proBNP. Clinical history was assessed at enrollment and during a median Follow-up of 23 months (IQR 9–40). The primary clinical endpoint was a composite of all cause mortality, aborted sudden cardiac death and sustained VT. Prespecified secondary surrogate endpoint included worsening heart failure (NYHA III–IV), non-sustained VT and sustained supraventricular tachycardia. Results: RA Systolic indexed volume (RASVi) correlated with LA Systolic indexed volume (LASVi) (r = 0.59, p 58 ml/m 2 ) had higher NT-proBNP levels, longer QRS duration, larger ventricle diameters, higher RV mass and lower peak oxygen uptake. RASVi was associated with the primary composite adverse event at univariate Cox-regression analysis (HR: 1.044, CI: 1.008–1.08, p = 0.01). Bayesian Multivariate model averaging revealed RASVi as predictor of secondary surrogate adverse outcome (HR: 1.06, CI: 1.053–1.068, Pb = 0,889). Conclusion: Among patients with repaired TOF, RA dilatation is an independent predictor for adverse clinical events. As such, routine assessment of RA volumes could be useful to further improve decision-making and management of these patients in the future