No abstract

Changes in Aspartate (Asp) concentrations are a potential biomarker of malate-aspartate shuttle dysfunction, as well as disturbances in the synthesis of NAA. J-difference editing allows the detection of a resolved Asp signal at δAsp ≈ 2.71ppm. This resonance has a complex shape and therefore approximation of the Asp signal is a challenging task. In our study we compare the performance of six Asp-approximation models applied to data from three brain regions (anterior cingulate gyrus (ACC), dorsolateral pre-frontal area (DLPFA) and visual cortex (VC)). A model consisting of four Gauss signals shows the best performance for all brain regions studied.

Background: Liver iron overload is a common diagnosis in patients with frequent blood transfusions. MRI is a promising non-invasive method for assessing liver iron concentration. We have created an MR-compatible phantom to develop a method for the standardization of T2* mapping and following conversion of T2* values (ms) into iron concentration (mg/mL) for an assessment of overload grade. Methods and Results: The standardization process involved the development of an MR-compatible phantom with solutions of paramagnetic iron oxide nanoparticles of various concentrations mimicking various degrees of liver iron overload. Using this phantom, we assessed the repeatability of T2* values obtained on reference MRI scanners (3T and 1.5T) at the D. Rogachev NMRCPHOI on 6 MRI acquisitions with one-week intervals. To assess the reproducibility of the results obtained on other MRI scanners, we compared these measurements with the reference values. Conclusion: The method for the standardization of T2* mapping on various 1.5T and 3T MRI scanners was tested. This method is based on the use of our phantom to validate or calibrate (if necessary) the MRI study protocol. The standardization protocol provided an opportunity to use the empirical formula (revealed in our institute as well as in other studies) for converting T2* values from any MRI scanner into LIC (mg/mL).