UNIVERSITÁ DIPISA
DOTTORATO DI RICERCA ININGEGNERIA DELL’INFORMAZIONE
N
OVEL METHODS FOR ACCELERATED DYNAMIC
MRI
DOCTORALTHESIS
Author
Giuseppe Valvano
Tutor (s)
Prof. Luigi Landini Eng. Nicola Martini, PhD
Supervisor at ETH - IBT
Prof. Dr. Sebastian Kozerke
Reviewer (s)
Prof. Michela Tosetti Prof. Anna Maria Bianchi
The Coordinator of the PhD Program
Prof. Marco Luise
Pisa, September 2016 XXIX
Summary of Ph. D. achievements
Summary of research activity
Activities
During these years the main topic of my research has been accelerated dynamic Mag-netic Resonance Imaging (MRI). In particular I focused on 4D Flow MRI, a high-throughput technique useful for the non invasive measurement of the temporal evo-lution blood velocities in-vivo. Several fast imaging methods have been investigated: non Cartesian acquisition trajectories, Compressed Sensing (CS) and Parallel Imaging, as well as their combination.
During the first half of my Ph. D., non Cartesian MRI has been investigated in combination to CS - MRI to achieve less coherent undersampled acquisitions, needed for CS purposes. Two acquisition strategies based on stack of variable density spirals have been proposed for 3D MRI and 2D dynamic MRI. Retrospective undersampling experiments have been performed to demonstrate the effectiveness of these trajectories. These experiments were carried on in collaboration with Fondazione Toscana Gabriele Monasterio (FTGM), CNR - Regione Toscana.
In the second half of my Ph. D. the collaboration with FTGM continued with the in-tention of developing a new reconstruction method for accelerated 4D Flow MRI. This research was carried on also in collaboration with the Institute for Biomedical Engineer-ing (IBT), University and ETH Zurich. At the IBT I was hosted from March 2015 to September 2015 by the Cardiovascular Magnetic Resonance (CMR) research group of Prof. Dr. Sebastian Kozerke. With their help I developed a new reconstruction method for undersampled 4D Flow MRI. The method, based on Low Rank plus Sparse Matrix Completion, has been validated by means of computer simulations and test in-vivo. I demonstrated better velocity estimation, compared to the state-of-the-art reconstruc-tion methods. During the visiting period in Zurich I also learnt how to program Philips MRI scanners and I started implementing the undersampled pulse sequence that I used during my experiments.
After this period in Zurich I continued my collaboration with FTGM and CMR -IBT, with the aim of optimizing the acquisition strategy and the computation time for the proposed reconstruction method. The developed method has been validated in-vivo
with data acquired from healthy volunteers. The method is currently under investigation by FTGM to assess its clinical value.
Main achievements
1. Developed new non Cartesian acquisition strategies for Compressed Sensing MRI. 2. Developed new reconstruction method for accelerated 4D Flow MRI.
Collaborations
1. Fondazione Toscana Gabriele Monasterio (FTGM), CNR - Regione Toscana (November 2013 - November 2016).
2. Institute for Biomedical Engineering (IBT), University and ETH Zurich (March 2015 - September 2015).
List of publications
International Journals
1. Giovannetti, G., Pingitore, A., Positano, V., De Marchi, D., Valvano, G., Gibiino, F., Aquaro G.D., Lombardi M., Landini L., Santarelli, M. F. (April, 2014). Im-proving sodium Magnetic Resonance in humans by design of a dedicated 23Na surface coil. Measurement, (Vol. 50, pp. 285-292).
2. Giovannetti, G., Valvano, G., Virgili, G., Giannoni, M., Flori, A., Frijia, F., De Marchi, D., Hartwig, V., Landini, L., Aquaro,G. D., and Pingitore, A., (November, 2015) Design and simulation of a dual-tuned 1H/23Na birdcage coil for MRS studies in human calf, Applied Magnic Resonance. (Vol. 46, Issue 11, pp. 1221-1238).
3. Santarelli, M.F., Positano, V., Martini, N., Valvano, G., Landini, L. (January, 2016). Technological innovations in Magnetic Resonance for early detection of cardiovascular diseases, Current Pharmaceutical Design. (Vol. 22, Number 1, pp. 77-89).
4. Valvano, G., Martini, N., Landini, L. and Santarelli, M. F. (July, 2016), Variable density randomized stack of spirals (VDR-SoS) for compressive sensing MRI. Magnetic Resonance in Medicine. (Vol. 76, Issue 1, pp.59-69).
5. Valvano, G., Martini, N., Huber, A., Santelli, C., Binter, C., Chiappino, D., Lan-dini, L., and Kozerke, S. (October, 2016), Accelerating 4D Flow MRI by Exploit-ing Low-rank Matrix Structure and Hadamard Sparsity. Magnetic Resonance in Medicine. (doi: 10.1002/mrm.26508)
International Conferences/Workshops with Peer Review
1. Valvano, G., Martini, N., Chiappino, D., Landini, L., Santarelli, M.F. (May, 2015) Random Delayed Spirals for Compressive Sensing Cine MRI. Proceedings 23rd meeting International Society Magnetic Resonance in Medicine(pp. 3633).
2. Valvano, G., Martini, N., Chiappino, D., Santarelli, M.F., Landini, L. (August, 2015) A novel 3D Cartesian random sampling strategy for Compressive Sensing Magnetic Resonance Imaging. Proceedings IEEE Engineering in Medicine and Biology Society, Milan 2015. (pp. 7502).
