Superparamagnetic-blocked state transition under alternating magnetic fields: towards determining the magnetic anisotropy in magnetic suspensions.

The potential of magnetic nanoparticles for acting as efficient catalysts, imaging tracers or heating mediators relays on their superparamagnetic behaviour under alternating magnetic fields. In spite of the relevance of this magnetic phenomenon, the identification of specific fingerprints to unequivocally assign superparamagnetic behaviour to nanomaterials is still lacking. Herein, we report on novel experimental and theoretical evidences related to the superparamagnetism observed in magnetic iron oxide nanoparticle suspensions at room temperature.

Accelerated multi-snapshot free-breathing mapping based on the dual refocusing echo acquisition mode technique (DREAM): An alternative to measure RF nonuniformity for cardiac MRI.

Background: Field inhomogeneities in MRI caused by interactions between the radiofrequency field and the patient anatomy can lead to artifacts and contrast variations, consequently degrading the overall image quality and thereby compromising diagnostic value of the images.

Purpose: To develop an efficient free-breathing and motion-robust mapping method that allows for the investigation of spatial homogeneity of the transmitted radiofrequency field in the myocardium at 3.0T.