Luis Agulles Pedrós 1

Research topics

08/01/2013

Luis Agulles Pedrós 2

• Hyperpolarized gases

• Monitoring of fruits ripening

• MRI Spectroscopy

• Diffusion and perfusion

• Fractional Fourier Transform

• X-ray phase contrast imaging

Research topics

08/01/2013

Medical Physics Master Thesis

Luis Agulles Pedrós 3

• Hyperpolarized gases

• Diffusion and perfusion

08/01/2013

Luis Agulles Pedrós 4

Gas transfer by artificial lung

• Use of porous membranes for blood oxygenation

• Possibility of continuous flow polarized Xe in liquid

Pore size ~ 0.03 µm

Gas

Liquid

Pump NMRCoil

Membrane

Gas

Hyperpolarized gases

08/01/2013 Paul Zänker’s work

Luis Agulles Pedrós 5

129Xe NMR spectra for different solvents

LipofundinD = 193.4 ppm

Albumin D = 197.7 ppm

Gelafundin D = 192.3 ppm

Glucose D = 203.7 ppm

gaseous Xe

NM

R s

igna

l [a

.u]

050100150200 050100150200

D

0

10

10

10

1

d [ppm]dissolved Xe

Delivery of polarized Xenon through membranes into

different potential carrier liquids possible without

destruction of polarization and bubbling

Hyperpolarized gases

08/01/2013 Paul Zänker’s work

Luis Agulles Pedrós 6

“volunteer”

3He applicator coil

10% 3He in 4He 10% 3He in N2 10% 3He in SF6

rati

o

(weak/s

trong

)

stro

ngly

diff

usi

on

weig

hte

d

weakly

diff

usi

on

weig

hte

db

= 3

890

0 s/

m2

b =

15

00 s

/m2

SNR gain is highest for large airspaces

(trachea).

SNR decreases from 4He to SF6

(slowed down of diffusion more

effectively by the heavier BG).

Ratio images can be obtained in the

smaller airspaces up to bronchi, clearly

visible for helium.

images of different gas mixtures for 2 different b-values

Acq. αr.f.

Gfreq

Gphase time

time

Hyperpolarized gases

08/01/2013

Luis Agulles Pedrós 7

• Hyperpolarized gases

• Diffusion and perfusionOn-going Master thesis“professionalizer”

08/01/2013

Luis Agulles Pedrós 8

Diffusion and perfusion

IVIM model )()0()( *

1 DDbbDS

bS efef

Koh et al. AJR, 160, p1352 june 2011Jensen NMR Biomed. 2010 August ; 23(7): 698–710

bDS

bS ef 1)0()(

6/ln 22)0()( KDbbDfS

bS

D: Diffusion D*: pseudo-diff, perfusionK: Kurtosis, Gausss. differ.f : Perfusion frac. (#D* vs. #D* )

>D

low b-val

Comparison of different approximations of the IVIM model in prostate cancer

08/01/2013

D* (velocity, distance): capillary

D: Gaussian distribution (PSF), tissue diff

Luis Agulles Pedrós 908/01/2013

f-map prostate

to improve: better fit, filters, more data…

Diffusion and perfusion

)()0()( *

1 DDbbDS

bS efef

bDS

bS ef 1)0()(

6/ln 22)0()( KDbbDfS

bS

Objectives: Comparison• Contrast• SNR• Acq. time• Optimization of parameters• …

bDS

bS e)0()(

Luis Agulles Pedrós 10

Questions?

08/01/2013