Periodic Reporting for period 1 - UniPAT (Universal Pulses for Parallel Transmission and Magnetic Resonance Imaging)
Okres sprawozdawczy: 2016-09-01 do 2018-02-28
The project went beyond the initial plan. For bigger impact, first a database of 10 maps of electromagnetic and static fields was built over 10 healthy subjects by using the commercially available 8Tx/8Rx Rapidbiomedical coil available on site. The maps were then used offline to design non selective and selective pulses to mitigate the RF inhomogeneity problem at 7T in T1-weighted (MPRAGE) and GRE2D sequences. The results showed great mitigation of the problem with minor impact on performance compared to the solutions tailored to the subjects. Seduced by those results, Siemens encouraged to repeat the demonstration on the Nova 8Tx/32Rx coil, which is their workhorse coil. Not having the coil on site, the instigators of UniPAT collaborated with the German Center of Neurodegenerative Diseases (DZNE) in Bonn to carry out the same scans at their site. A database of 10 subjects thus again was built and the robust solutions were tested on an additional set of 10 volunteers. The results were even more successful given the higher coil performance. Later, similar "calibration-free", universal, pulses were designed for refocusing purposes, highly required for T2-weighted sequences. The latter sequences are particularly sensitive to RF field inhomogeneities and simply yield non-exploitable images unless proper measures are taken. Through the use of a sophisticated analysis, such solutions could be determined yet with great simplicity, versatility, and they were validated again in Bonn on 5 subjects. Finally, because scanner tuning variability may exist across sites, the pulses were sent to a couple of additional laboratories having the same set up (University of Minnesota and University of Maastricht) to blindly try the plug and play solutions. The universal pulses again greatly outperformed the standard approaches, demonstrating the robustness of the technique. The work above has led to 2 publications (in open access) and 7 abstracts. A powerful toolbox has been programmed to design solutions virtually covering all 3D MRI applications. Incidentally, this work has also pushed the safety studies in order to boost RF pulse performance while guaranteeing subject's safety.
The outcomes of the project have been presented at several conferences/workshops and at some coil manufacturer's site. An external sub-contractor was also hired to study the commercial value of the corresponding patent and invention. In the end, dealing with the main scanner manufacturers was advised and a few business-oriented discussions have taken place with the leading one. In the meantime, the same company however has developed its own tools to address the calibration problem mentioned above. Many efforts have been made in that regard to speed up the procedure so that universal pulses are for the moment not considered a priority. Nevertheless, no feedback from users is available yet, so that time will tell whether the calibration-free pulses developped in UniPAT have a commercial future. It remains indeed that many academic sites across the world have expressed an interest for acquiring such solutions. Downloadable products with expirable licenses are currently being elaborated to maximize dissemination and exposure.