MRI Portable Devices for Medical Environments. Javier Alonso - PowerPoint PPT Presentation

MRI Portable Devices for Medical Environments. Javier Alonso Valdesueiro. Ph.D. Science and Technology Faculty, Electricity and Electronics UPV/EHU.

lfpMRI 2

So… what for today? RF-MAFS project. Or how we deal with nuclear interactions, • magnetic susceptibility changes, patient movements, etc. in MRI experiments at low field. MRI-Magnetsome project. Or how we increase SNR of MR • images at the same time we don’t poison anyone Also it would be nice if we could target cancer cells in the process. lfpHyperpol project. Or how we plan to increase our NMR • signal so we can carry out spectroscopy wit our equipment. 3

Spectral and Image Resolution Resolution of the Spectral lines In MRI we add: in Solid State NMR: Magnetic susceptibility. • Dipolar Interaction. • Magnetic field in- • homogeneities. Chemical Shift Anisotropy. • Patient movements. • Quadrupolar Interaction. • [2] [1] [1] University of Ottawa NMR Facility Blog, June 4, 2008. [2] MRI Artifacts Seminar, ICAN School of Medicine at Mount Sinai Hospital, New York 4

Magic Angle Spinning Spin the Sample: Spin the Sample: [1] [2] (a) The mouse-MAS probe; (b) 85 MHz 1H NMR image of the part of the (live) mouse body between the arrows shown in (a). 85MHz in-vivo 1H spectra of a 8mm x Magic Angle Spinning: 8mm x 8mm volume in • Sample Tilted 54.74° wrt the the liver of a live indicated as 1 using (a) main magnetic field. static NMR (b) 4Hz • Sample Spun at frequencies [1] University of Ottawa NMR F acility Blog, June 4, 2008. spinning technique and between 15 kHz and 100 kHz. (c) ex-vivo NMR . [2] Wind R.A., Hu J.Z., Rommereim D.N., “High-resolution 1H NMR spectroscopy in • DDC cancelled and CSA and a live mouse subjected to 1.5 Hz magic angle spinning,” Magn Reson Med. vol 50(6), pp. 1113-9, 2003 December . MSC averaged.

Magic Angle Field Spinning Spin the Magnetic Field: Very Low Spinning Frequencies: ω r B 0 =B z’ y Forget to average completely the anisotropies. Rotating Power θ RF Probe z transfer z’ z’ B RF [3] θ θ z z G z’ =dB 0 /dz’=dB z’ /dz’ Enormous Weight and Instrumentation: x Forget to deploy the device in Mobile/Emergency medical environments. [4] [3] McGinley J. V. M., Ristic M., Young I. R., “A permanent MRI magnet for magic angle imaging having its field parallel to the poles, ” J. Magn. Reson. Vol. 271, pp. 60-67, 2016 [4] Sakellariou D., Hugon C., Guiga A., Aubert G., Cazaux S., Hardy P., “Permanent magnet assembly producing a strong tilted homogeneous magnetic field: towards magic angle field spinning NMR and MRI,” Magn. Reson. Chem. Vol. 48 (12), pp. 903-908, 2010 6

RF-MFAS Concept Magnetic System: • Proof of Concept. • Ongoing work. 2 RF coils fed in opposite phase • producing Bt. 1 Electromagnet producing Bl. • evaluating B0 NMR spectrometer and probe. • • Maximum Magnetic Field Intensity. MRI Gradient system. • • Cylindrical Volume of Homogeneity 30x30mm. 7

RF-MFAS Electromagnet Rotating Magnetic Field: Bx a = 28º (mT) By a = 29.5º (mT) Bx (mT) By (mT) 1.8 1.7 1.6 B x (mT) B y (mT) 1.5 1.4 1.3 1.2 1.1 1 -200 -150 -100 -50 0 50 100 150 200 Z (mm) Diameters: • Out. Coil OD/ID: 70.8/68. • Inn. Coil OD/ID: 66.8/64. Fields: • Out. Coil By ~ 1.4 mT/Arms. • Inn. Coil Bx ~ 1.6 mT/Arms. 8

RF-MFAS Electromagnet 0.06 0.04 Error B 1 0º B 2 /B 1 60º 0.05 120º 0.03 180º 0.04 240º 300º 0.02 0.03 Error D 1 0.02 0.01 0.01 0 0 -0.01 -0.01 -120 -80 -40 0 40 80 120 -150 -100 -50 0 50 100 Z (mm) Z (mm) 0.06 0.035 0º Error B 2 60º 0.03 • Strong angular 0.05 B 1 /B 2 120º 180º 0.025 dependence. 0.04 240º 300º 0.02 • Miss-alignment 0.03 Error 0.015 D 2 between layers. 0.02 0.01 • Angular current 0.01 0.005 distribution. 0 0 -0.01 -0.005 -120 -80 -40 0 40 80 120 -150 -100 -50 0 50 100 9 Z (mm) Z (mm)

RF-MFAS Electromagnet Longitudinal Magnetic Field: a) b) 0.1 r s1 90 mm 90/140 mm 0.08 r 110/140 mm s2 110/140* mm D B ( % ) 0.06 Design: • Simulations and 0.04 optimizations. r s1 r s2 0.02 • Power Constraint 2 2 30W. 0 -20 -15 -10 -5 0 5 10 15 20 • Diameter constraint z ( mm ) c) 280 mm. Construction: • 3D printed parts. Z (m) Z (m) B (mT) • Home-made winding. x (m) x (m) 10

RF-MFAS Electromagnet Longitudinal Magnetic Field: 2.2 B z Simulations 2.1 B z Central Z-Axis B z (mT/A rms ) 2 1.9 • Homogeneity region extends 80 mm. 1.8 • Bz ~ 2mT/A. • Same 15 mm axis 1.7 measured. • Noise around 60µT. 1.6 -80 -60 -40 -20 0 20 40 60 80 Z (mm) 11

RF-MFAS Electromagnet Longitudinal Magnetic Field: 0.0014 Central HS 0.0012 15 mm HS at 0º 15 mm HS at 60º 0.001 15 mm HS at 120º 15 mm HS at 180º 0.0008 Error 0.0006 0.0004 0.0002 0 -0.0002 -20 -15 -10 -5 0 5 10 15 20 Z (mm) • Very good cylindrical symmetry. • Deviation at z = 0 less than 60µT. 12

RF-MFAS Spectrometer This is where we are: L NMR 1Ω 13

RF-MFAS Spectrometer This is where we are: Coils: • TX Coil: 3 turns saddle coil 14 mm diameter. • RX Coil: 11 turns DHD coil tilted at 38°. • 40 dB isolation when position is optimized. Amplification Chain: • Gv = 10 for each stage. • 3 stages protected by crossed diodes. • SR560 added at the end of the chain. 14

T 1 , 2 -MR Image enhancement TR TE [5] (msec) (msec) T1-Weighted (short TR and 500 14 TE) T2-Weighted 4000 90 (long TR and TE) Flair (very long TR 9000 114 and TE) Tissue T1-Weighted T2-Weighted Flair CSF Dark Bright Dark White Matter Light Dark Gray Dark Gray Cortex Gray Light Gray Light Gray Fat Bright Light Light [5] http://casemed.case.edu/clerkships/neurology/web%20neur orad/mri%20basics.htm Inflammation (infection, Dark Bright Bright demyelinatio n) 15

T 1 , 2 -MR Image enhancement • Biological hazard at high concentrations. • Low concentrations (mM) typically used. • Low concentrations lead to long pulse sequences and low contrast changes. What the Nature Offers 16

T 1 , 2 -MR Image enhancement Our Approach: [6] • Step 1: Functionalization of the shell. ✔ • Step 2: Analysis of the attached molecules. ✔ • Step 3: absorption rate of the cancer cells. • Step 4: In-vitro imaging of cells [6] M. A. Abakumov, N. V. Nukolova, M. Sokolsky-Papkov, S. A. Shein, T. O. Sandalova, H. M. Vishwasrao, N. F. Grinenko, I. L. Gubsky, A. M. Abakumov, Al. V. Kabanov, Vl. P. Chekhonin, “VEGF-targeted magnetic nanoparticles for MRI visualization of brain tumor,” Nanomed. Nanotech. Bio. Med., vol. 11 (4), pp. 825-833, 2015 . 17

T 1 , 2 -MR Image enhancement Lunch Time!!! Porcentaje de concentracion Concentraciones totales extraidas 100 150 control 200 mM 90 extracc. 100 mM 80 50 mM 100 25 mM 35 µg/mL 70 0 mM % mM 60 50 50 40 30 20 0 0 50 100 150 200 0 50 100 150 18 200 concentracion [mM] concentracion [mM]

Low Field Hyperopolarization [7] • Nano-Particle base Hyperpolarizator. • Portable and Cryo-Free apparatus. • Future Funding applications [7] A. Ajoy, R. Nazaryan, E. Druga, K. Liu, A. Aguilar, B. Han, M. Gierth, J. T. Oon, B. Safvati, R. Tsang, J. H. Walton, D. Suter, C. A. Meriles, J. A. Reimer, and A. Pines, “Room temperature “Optical Nanodiamond Hyperpolarizer”: physics, design and operation,” arXiv: 1811.10218v1, 2018 . 19

Acks Funding: MSCA-IF: RF MAFS project with action number 750445. Basque Country Government: Education, Politics, Language and Culture Department of the Basque Country Government, through project with ref. IT1104-16. RF Group Beatriz Sisniega, MSc. : Magnetic Measurements and Magnet design. Julen Urtaza, Gr. St.: Electronics and positioning system. Juan Mari Collantes: Project Coordination and RF insight. Libe, Popi, Aitziber, Nerea, Joaquín: MIMASPEC Group Support and discussions. Irati Rodrigo: Measurment system and callibration. Jorge Pérez: Numerical Simulations GMMM at UPV/EHU Lourdes Marcano: Magnetsome growth and manipulation 20

THANK YOU Engineering for Medical Applications. Sep. 11 th -13 th Bilbao, Spain. 21

Measurement System 22

Inner DHD Coil Spatial Measurements 1.7 Bx int (mT) Bx pos1 (mT) 1.6 Bx pos2 (mT) Bx pos3 (mT) Bx pos4 (mT) 1.5 Bx (mT) Bx pos5 (mT) Bx pos6 (mT) 1.4 1.3 1.2 -100 -50 0 50 100 150 Z (mm) 23

Outer DHD Coil Spatial Measurements 1.7 By int (mT) By pos1 (mT) 1.6 By pos2 (mT) By pos3 (mT) By pos4 (mT) 1.5 By (mT) By pos5 (mT) By pos6 (mT) 1.4 1.3 1.2 -100 -50 0 50 100 150 Z (mm) 24

Measurement System 25

Power Matching Network 26

Espectro CH 3 Control 6 12 x 10 200 mM 10 100 mM 50 mM 8 25 mM 6 a.u. 4 2 0 -2 4400 4500 4600 4700 4800 4900 f [kHz] 27

5 Espectro CH 3 despues de Extraccion 20 x 10 200 mM 100 mM 15 50 mM 25 mM 10 a.u 5 0 -5 4400 4500 4600 4700 4800 4900 f [kHz] 28