th - 1987 - 51st ENC Conference
th - 1987 - 51st ENC Conference
th - 1987 - 51st ENC Conference
You also want an ePaper? Increase the reach of your titles
YUMPU automatically turns print PDFs into web optimized ePapers that Google loves.
MF73<br />
OXYGEN-17 MAGNETIC RESONANCE IMAGING (OMRI)<br />
G. D. Mateescu and Terri Dular<br />
Department of Chemistry, Case Western Reserve University<br />
Cleveland, Ohio 44106<br />
In spite of <strong>th</strong>e primordial importance of oxygen in llfe processes and in<br />
many fields of chemistry, imaging wi<strong>th</strong> oxygen-17 has not yet been attempted.<br />
This is due to <strong>th</strong>e fact <strong>th</strong>at O-17 has generally been considered impractical for<br />
MRI, owing to its "unfavorable" properties: very low natural abundance, low<br />
natural sensitivity, and considerable quadrupolar broadening.<br />
We report <strong>th</strong>e first 170 imaging experiments and present evidence <strong>th</strong>at <strong>th</strong>e<br />
above mentioned "drawbacks" can be turned into advantages. In <strong>th</strong>e absence of<br />
specialized equipment, our approach was es-<br />
sentially <strong>th</strong>e same as in Lauterbur's histo-<br />
rical endeavor. The results shown in Figure<br />
1 are selfexplanatory . Fur<strong>th</strong>er experi-<br />
ments demonstrated <strong>th</strong>e feasibility of OMRI<br />
wi<strong>th</strong> plants, animal blood, brain, kidney,<br />
heart, muscle, fat, eggs, as well as non-<br />
biological matter. Contrasts from drastic<br />
to very subtle can be obtained in TI, T2,<br />
density, and flow measurements. A dramatic<br />
"Reverse Gradient Imaging" was obtained<br />
wi<strong>th</strong> signals from water in extreme (bound &<br />
DOG BLOOD (b)<br />
Natural a b u n ~<br />
lATER<br />
Natural abundance<br />
! t I<br />
i i i<br />
i i<br />
• I I<br />
g~<br />
Z-gradient<br />
0.2 G/cm<br />
free) states. Combining IH and 170 imaging Figure I. O*yge,-17 Magnetlc Resonance Imaging.<br />
(a) Two NH,q tubes (5mm OD) containing distilled<br />
water, placed in a 16mm tube containing CDC1].<br />
proves to be useful. 170 is a better repre- (b) Two NMR tubes containing dog blood. 1200 90 °<br />
pulses at O.l s intervals per trace. Varian XL-<br />
200 at 27.12 ~z. We expect a >80 times better<br />
sentative of <strong>th</strong>e H20 molecule. Its relaxa- resolution wi<strong>th</strong> <strong>th</strong>e 20G/cm mlcrolmager co be in-<br />
stalled In February <strong>1987</strong> on our Bruker MSL-&O0<br />
tlon depends essentially on intramolecular (local protein, nucleic acid,<br />
lipid, sugar) electric field gradients; also, 170 relaxation is mainly affected<br />
by <strong>th</strong>e exchange of <strong>th</strong>e entire water molecule and, to a lesser extent, by proton<br />
or deuteron exchange. Parallel imaging of o<strong>th</strong>er nuclei will also be presented.<br />
(a)
Change language