Investigation of multichannel phased array performance for fetal MR imaging on 1.5T clinical MR system

[摘要] Fetal MRI on 1.5T clinical scanner has been increasingly becoming a powerful imaging tool for studying fetal brainabnormalities in vivo. Due to limited availability of dedicated fetal phased arrays, commercial torso or cardiac phased arraysare routinely used for fetal scans, which are unable to provide optimized SNR and parallel imaging performance with a smallnumber coil elements, and insufficient coverage and filling factor. This poses a demand for the investigation and developmentof dedicated and efficient radiofrequency (RF) hardware to improve fetal imaging. In this work, an investigational approachto simulate the performance of multichannel flexible phased arrays is proposed to find a better solution to fetal MRimaging. A 32 channel fetal array is presented to increase coil sensitivity, coverage and parallel imaging performance. Theelectromagnetic field distribution of each element of the fetal array is numerically simulated by using finite-difference timedomain(FDTD) method. The array performance, including B1 coverage, parallel reconstructed images and artifact power,is then theoretically calculated and compared with the torso array. Study results show that the proposed array is capable ofincreasing B1 field strength as well as sensitivity homogeneity in the entire area of uterus. This would ensure high qualityimaging regardless of the location of the fetus in the uterus. In addition, the paralleling imaging performance of the proposedfetal array is validated by using artifact power comparison with torso array. These results demonstrate the feasibility of the 32channel flexible array for fetal MR imaging at 1.5T.

[学科分类] 外科医学