Simultaneous T(2) and T(2)* mapping of multiple sclerosis lesions with radial RARE-EPI

PURPOSE: The characteristic MRI features of multiple sclerosis (MS) lesions make it conceptually appealing to pursue parametric mapping techniques that support simultaneous generation of quantitative maps of 2 or more MR contrast mechanisms. We present a modular rapid acquisition with relaxation enhancement (RARE)‐EPI hybrid that facilitates simultaneous T(2) and T(2)* mapping (2in1‐RARE‐EPI). METHODS: In 2in1‐RARE‐EPI the first echoes in the echo train are acquired with a RARE module, later echoes are acquired with an EPI module. To define the fraction of echoes covered by the RARE and EPI module, an error analysis of T(2) and T(2)* was conducted with Monte Carlo simulations. Radial k‐space (under)sampling was implemented for acceleration (R = 2). The feasibility of 2in1‐RARE‐EPI for simultaneous T(2) and T(2)* mapping was examined in a phantom study mimicking T(2) and T(2)* relaxation times of the brain. For validation, 2in1‐RARE‐EPI was benchmarked versus multi spin‐echo (MSE) and multi gradient‐echo (MGRE) techniques. The clinical applicability of 2in1‐RARE‐EPI was demonstrated in healthy subjects and MS patients. RESULTS: There was a good agreement between T(2)/T(2)* values derived from 2in1‐RARE‐EPI and T(2)/T(2)* reference values obtained from MSE and MGRE in both phantoms and healthy subjects. In patients, MS lesions in T(2) and T(2)* maps deduced from 2in1‐RARE‐EPI could be just as clearly delineated as in reference maps calculated from MSE/MGRE. CONCLUSION: This work demonstrates the feasibility of radially (under)sampled 2in1‐RARE‐EPI for simultaneous T(2) and T(2)* mapping in MS patients

Cardiorenal sodium MRI in small rodents using a quadrature birdcage volume resonator at 9.4 T

OBECTIVE: Design, implementation, evaluation and application of a quadrature birdcage radiofrequency (RF) resonator tailored for renal and cardiac sodium ((23)Na) magnetic resonance imaging (MRI) in rats at 9.4 T. MATERIALS AND METHODS: A low pass birdcage resonator (16 rungs, d(in) = 62 mm) was developed. The transmission field (B(1)(+)) was examined with EMF simulations. The scattering parameter (S-parameter) and the quality factor (Q-factor) were measured. For experimental validation B(1)(+)-field maps were acquired with the double-angle method. In vivo sodium imaging of the heart (spatial resolution: (1 × 1 × 5) mm(3)) and kidney (spatial resolution: (1 × 1 × 10) mm(3)) was performed with a FLASH technique. RESULTS: The RF resonator exhibits RF characteristics, transmission field homogeneity and penetration that afford (23)Na MR in vivo imaging of the kidney and heart at 9.4 T. For the renal cortex and medulla a SNRs of 8 and 13 were obtained and a SNRs of 14 and 15 were observed for the left and right ventricle. DISCUSSION: These initial results obtained in vivo in rats using the quadrature birdcage volume RF resonator for (23)Na MRI permit dedicated studies on experimental models of cardiac and renal diseases, which would contribute to translational research of the cardiorenal syndrome

Effects of Al-, Ti- and Zn-containing nanomaterials on cell lines in vitro

International audience52nd Congress of the European-Societies-of-Toxicology (EUROTOX), Seville, Spain

Effects of Al-, Ti- and Zn-containing nanomaterials on cell lines in vitro

International audience52nd Congress of the European-Societies-of-Toxicology (EUROTOX), Seville, Spain