<s>
Sodium	B-Algorithm
MRI	I-Algorithm
(	O
also	O
known	O
as	O
23Na-MRI	O
)	O
is	O
a	O
specialised	O
magnetic	O
resonance	O
imaging	O
technique	O
that	O
uses	O
strong	O
magnetic	O
fields	O
,	O
magnetic	O
field	O
gradients	O
,	O
and	O
radio	O
waves	O
to	O
generate	O
images	O
of	O
the	O
distribution	O
of	O
sodium	O
in	O
the	O
body	O
,	O
as	O
opposed	O
to	O
more	O
common	O
forms	O
of	O
MRI	B-Algorithm
that	O
utilise	O
protons	B-Application
(	O
or	O
hydrogen	O
)	O
present	O
in	O
water	O
(	O
1H-MRI	O
)	O
.	O
</s>
<s>
Like	O
the	O
proton	B-Application
,	O
sodium	O
is	O
naturally	O
abundant	O
in	O
the	O
body	O
,	O
so	O
can	O
be	O
imaged	O
directly	O
without	O
the	O
need	O
for	O
contrast	B-Algorithm
agents	I-Algorithm
or	O
hyperpolarization	O
.	O
</s>
<s>
In	O
contrast	O
to	O
conventional	O
MRI	B-Algorithm
of	O
the	O
proton	B-Application
,	O
Sodium	B-Algorithm
MRI	I-Algorithm
is	O
complicated	O
by	O
the	O
low	O
concentrations	O
of	O
Na	O
nuclei	O
relative	O
to	O
concentration	O
of	O
H2O	O
molecules	O
in	O
biological	O
tissues	O
(	O
10-45	O
mM	O
)	O
and	O
the	O
lower	O
gyromagnetic	O
ratio	O
of	O
the	O
23Na	O
nucleus	O
as	O
compared	O
to	O
a	O
1H	O
nucleus	O
,	O
.	O
</s>
<s>
The	O
quadrupolar	O
23Na	O
nucleus	O
also	O
has	O
a	O
faster	O
transverse	B-Algorithm
relaxation	I-Algorithm
rates	O
and	O
multiple	O
quantum	O
coherences	O
as	O
compared	O
to	O
the	O
1H	O
nucleus	O
,	O
requiring	O
specialized	O
and	O
high	O
performance	O
MRI	B-Algorithm
sequences	I-Algorithm
to	O
capture	O
information	O
before	O
the	O
contrast	O
used	O
to	O
image	O
the	O
body	O
is	O
lost	O
.	O
</s>
<s>
After	O
exhaustive	O
exercise	O
,	O
for	O
example	O
,	O
23Na	O
MRI	B-Algorithm
can	O
detect	O
Na+	O
levels	O
in	O
tissues	O
rising	O
sharply	O
,	O
and	O
can	O
even	O
visualize	O
a	O
sodium-rich	O
meal	O
in	O
a	O
patient	O
’s	O
stomach	O
.	O
</s>
<s>
To	O
compensate	O
,	O
Na+	O
ions	O
from	O
the	O
extracellular	O
space	O
are	O
exchanged	O
for	O
protons	B-Application
in	O
the	O
Na+	O
/H	O
+	O
antiport	O
,	O
the	O
loss	O
of	O
which	O
often	O
attenuates	O
cancer	O
growth	O
.	O
</s>
<s>
Therefore	O
,	O
23Na	O
MRI	B-Algorithm
is	O
a	O
useful	O
clinical	O
tool	O
for	O
detecting	O
a	O
number	O
of	O
disease	O
states	O
,	O
including	O
heart	O
disease	O
and	O
cancer	O
,	O
as	O
well	O
as	O
monitoring	O
therapy	O
.	O
</s>
<s>
For	O
example	O
,	O
23Na	O
MRI	B-Algorithm
has	O
been	O
shown	O
to	O
measure	O
cellularity	O
in	O
ovarian	O
cancer	O
.	O
</s>
<s>
Tissue	O
damage	O
in	O
stroke	O
patients	O
can	O
also	O
be	O
evaluated	O
using	O
23Na	O
MRI	B-Algorithm
,	O
with	O
one	O
study	O
showing	O
that	O
a	O
change	O
of	O
50%	O
higher	O
TSC	O
than	O
the	O
TSC	O
in	O
healthy	O
brain	O
tissue	O
is	O
consistent	O
with	O
complete	O
infarction	O
,	O
and	O
therefore	O
can	O
be	O
used	O
to	O
determine	O
tissue	O
viability	O
and	O
treatment	O
options	O
for	O
the	O
patient	O
.	O
</s>
<s>
Another	O
interesting	O
use	O
of	O
23Na	O
MRI	B-Algorithm
is	O
in	O
evaluating	O
multiple	O
sclerosis	O
,	O
wherein	O
accumulation	O
of	O
sodium	O
in	O
axons	O
can	O
lead	O
to	O
axon	O
degeneration	O
.	O
</s>
<s>
Recently	O
,	O
work	O
has	O
been	O
undertaken	O
to	O
assess	O
the	O
utility	O
of	O
using	O
sodium-MRI	O
to	O
characterize	O
prostate	O
cancer	O
lesions	O
in	O
men	O
.	O
</s>
<s>
In	O
this	O
study	O
,	O
patients	O
were	O
imaged	O
with	O
sodium	B-Algorithm
MRI	I-Algorithm
prior	O
to	O
surgical	O
removal	O
of	O
the	O
prostate	O
.	O
</s>
<s>
This	O
preliminary	O
study	O
suggests	O
that	O
sodium	B-Algorithm
MRI	I-Algorithm
can	O
accurately	O
characterize	O
the	O
stage	O
of	O
prostate	O
cancer	O
.	O
</s>
<s>
This	O
suggests	O
the	O
potential	O
use	O
of	O
sodium-MRI	O
to	O
better	O
management	O
and	O
stage	O
patients	O
with	O
prostate	O
cancer	O
into	O
treatment	O
schemes	O
.	O
</s>
<s>
23Na	O
MRI	B-Algorithm
measures	O
cellular	O
metabolic	O
rate	O
as	O
well	O
as	O
disease-related	O
change	O
in	O
tissues	O
and	O
organs	O
.	O
</s>
<s>
Unlike	O
other	O
MRI	B-Algorithm
scanning	O
,	O
sodium	B-Algorithm
MRI	I-Algorithm
captures	O
only	O
sodium	O
signals	O
inside	O
bodies	O
.	O
</s>
<s>
Both	O
proteoglycan	O
and	O
sodium	O
level	O
decrease	O
,	O
so	O
less	O
signals	O
are	O
observed	O
by	O
sodium	B-Algorithm
MRI	I-Algorithm
.	O
</s>
<s>
23Na	O
MRI	B-Algorithm
is	O
very	O
sensitive	O
and	O
specific	O
to	O
change	O
in	O
proteoglycan	O
,	O
so	O
it	O
is	O
good	O
to	O
use	O
for	O
monitoring	O
of	O
proteoglycan	O
degeneration	O
in	O
cartilage	O
.	O
</s>
