Periodic Reporting for period 2 - B-Q MINDED (Breakthroughs in Quantitative Magnetic resonance ImagiNg for improved DEtection of brainDiseases)
Okres sprawozdawczy: 2020-01-01 do 2022-03-31
B-Q MINDED aims to overcome the current barriers by developing widely-applicable post-processing breakthroughs for accelerating Q-MRI. The originality of B-Q MINDED lies in its ambition to replace the conventional rigid multi-step processing pipeline with an integrated single-step parameter estimation framework. This approach will unlock a wealth of options for optimization of Q-MRI. To accomplish this goal, B-Q MINDED follows a collaborative cross-disciplinary approach (from basic MR physics to clinical applications) with strong involvement of industry (two MRI vendors and two MRI-software SMEs).
B-Q MINDED provides a unique training platform that enables young European researchers to develop a holistic view on Q-MRI research and development. The fellows enrolled in B-Q MINDED have access to a variety of network-wide training events and gain essential transferable skills that will positively affect their employability in academia and industry. By combining research, innovation, and education, B-Q MINDED aims to pave the way for introducing Q-MRI into the clinic.
The main results achieved so far can be summarized as follows:
● Neural networks were implemented for T1 relaxometry mapping. Preliminary results indicate that these networks are able to produce relaxometry maps with higher precision than conventional T1 mapping methods.
● A theoretical time-efficiency metric was developed to compare acquisition settings for a highly accelerated intra-scan modulated acquisition. The metric was used to find time-efficient undersampling patterns for 3D-inversion prepared fast spin echo acquisition which allows mapping T1 and T2 at high acceleration factors, beyond those
possible with parallel imaging.
● A proof-of-concept framework was developed that augments T1 super-resolution reconstruction with optimal experiment design.
● A framework to reduce scan times in diffusion MRI was developed by blending diffusion parameter estimation and intra-scan contrast modulation. Simulation results have shown that using this joint model-based framework, diffusion parameters can be estimated more accurately and precisely than with conventional methods.
● Multislice EPI, FLASH and RARE sequences for fast read-out were tested and compared for super-resolution purposes. T1 mapping techniques were optimized based on gradient echo sequences with focus on parameters selection, spoiling and steady state.
● Quantitative echo planar imaging (QUTE) for T2* mapping has been implemented for a large number of echoes. Using an intra-scan modulation approach that combines image reconstruction and parameter estimation in a joint framework, it was shown that it is possible to substantially reduce the acquisition time compared to the
conventional QUTE imaging sequence.
● A generative numerical model for myocardium microstructure has been generated to simulate the diffusion MRI signal at a sub-voxel scale.
● Methods have been studied to standardize brain MRI diffusion maps for multi-centre studies. State-of-the-art data harmonization methods to reduce the between-subject variability in the population data (such as ComBat) were implemented and are being used as benchmark for novel standardization developments.
● Outlier rejection methods have been implemented to reduce within-subject variability of diffusion tensor imaging and diffusion kurtosis imaging parameters. The performance of these outlier rejection methods were quantified in terms of improved reproducibility and improved sensitivity for pathology.
● A super-resolution reconstruction method for T2* mapping for quantitative musculoskeletal MRI has been developed and implemented on a clinical MRI system.
● Segmentation algorithms that are conventionally applied to structural MRI data (e.g. T1-weighted images) have been adapted for quantitative T1 maps.
● 2D and 3D radial pulse sequences were implemented and signal corrections for echo alignment were developed for 3D radial pulse sequences. This will allow acquisitions with a very short echo time.