<s>
Synthetic	B-Algorithm
MRI	I-Algorithm
is	O
a	O
simulation	O
method	O
in	O
Magnetic	O
Resonance	O
Imaging	O
(	O
MRI	B-Algorithm
)	O
,	O
for	O
generating	O
contrast	O
weighted	O
images	O
based	O
on	O
measurement	O
of	O
tissue	O
properties	O
.	O
</s>
<s>
This	O
is	O
different	O
from	O
conventional	O
MRI	B-Algorithm
,	O
where	O
the	O
signal	O
acquired	O
from	O
the	O
tissue	O
is	O
used	O
to	O
generate	O
an	O
image	O
directly	O
,	O
often	O
generating	O
only	O
one	O
contrast	O
weighting	O
per	O
acquisition	O
.	O
</s>
<s>
The	O
synthetic	O
images	O
are	O
similar	O
in	O
appearance	O
to	O
those	O
normally	O
acquired	O
with	O
an	O
MRI	B-Algorithm
scanner	O
.	O
</s>
<s>
The	O
parametric	O
maps	O
can	O
be	O
computed	O
from	O
a	O
particular	O
MRI	B-Algorithm
acquisition	O
designed	O
to	O
measure	O
the	O
tissue	O
parameters	O
,	O
known	O
as	O
quantification	O
.	O
</s>
<s>
Using	O
the	O
maps	O
,	O
which	O
contains	O
the	O
measured	O
parameters	O
for	O
each	O
voxel	B-Algorithm
,	O
virtual	O
scanner	O
settings	O
that	O
correspond	O
to	O
those	O
used	O
in	O
conventional	O
scan	O
are	O
given	O
.	O
</s>
<s>
These	O
settings	O
can	O
be	O
echo	O
time	O
(	O
TE	O
)	O
and	O
repetition	O
time	O
(	O
TR	O
)	O
for	O
a	O
spin-echo	O
(	O
SE	O
)	O
sequence	O
or	O
TE	O
,	O
TR	O
and	O
inversion	O
time	O
(	O
TI	O
)	O
for	O
an	O
inversion	O
recovery	O
(	O
IR	O
,	O
FLAIR	B-Algorithm
,	O
STIR	O
,	O
PSIR	O
,	O
FSE-IR	O
,	O
TIRM	O
)	O
sequence	O
.	O
</s>
<s>
Synthetic	B-Algorithm
MRI	I-Algorithm
was	O
proposed	O
as	O
early	O
as	O
1984	O
Bielke	O
et	O
al	O
.	O
</s>
<s>
This	O
new	O
acquisition	O
method	O
performs	O
8	O
acquisitions	O
at	O
4	O
different	O
excitation	O
delays	O
,	O
giving	O
8	O
values	O
to	O
estimate	O
T1	B-Algorithm
,	O
T2	B-Algorithm
,	O
PD	O
and	O
M0	O
for	O
each	O
imaged	O
voxel	B-Algorithm
.	O
</s>
<s>
This	O
method	O
uses	O
a	O
randomized	O
acquisition	O
that	O
creates	O
a	O
unique	O
response	O
depending	O
on	O
T1-T2-PD	O
values	O
of	O
a	O
voxel	B-Algorithm
.	O
</s>
<s>
This	O
unique	O
response	O
is	O
then	O
matched	O
against	O
a	O
database	O
of	O
response	O
from	O
all	O
possible	O
T1-T2-PD	O
combinations	O
.	O
</s>
<s>
This	O
is	O
different	O
from	O
acquiring	O
the	O
images	O
directly	O
on	O
the	O
MRI	B-Algorithm
scanner	O
with	O
a	O
pulse	O
sequence	O
where	O
it	O
might	O
take	O
several	O
minutes	O
to	O
get	O
new	O
images	O
with	O
different	O
settings	O
.	O
</s>
<s>
Synthetic	B-Algorithm
MRI	I-Algorithm
also	O
enables	O
the	O
possibility	O
to	O
create	O
new	O
image	O
contrast	O
weightings	O
after	O
the	O
scan	O
has	O
been	O
completed	O
and	O
the	O
patient	O
has	O
left	O
the	O
hospital	O
.	O
</s>
<s>
A	O
prospective	O
multi-reader	O
,	O
multi-case	O
,	O
multi-center	O
clinical	O
trial	O
of	O
overall	O
image	O
quality	O
of	O
synthetic	B-Algorithm
MRI	I-Algorithm
compared	O
to	O
conventional	O
MRI	B-Algorithm
in	O
a	O
general	O
neuroimaging	O
population	O
has	O
shown	O
that	O
synthetic	B-Algorithm
MRI	I-Algorithm
is	O
non-inferior	O
to	O
conventional	O
imaging	O
.	O
</s>
<s>
Synthetic	B-Algorithm
MRI	I-Algorithm
is	O
based	O
on	O
parametric	O
maps	O
.	O
</s>
<s>
The	O
parametric	O
maps	O
can	O
for	O
example	O
be	O
longitudinal	O
(	O
T1	B-Algorithm
)	O
and	O
transversal	O
(	O
T2	B-Algorithm
)	O
relaxation	B-Algorithm
times	O
as	O
well	O
as	O
either	O
proton	O
density	O
(	O
PD	O
)	O
or	O
apparent	O
equilibrium	O
magnetization	O
(	O
M0	O
)	O
.	O
</s>
<s>
The	O
signal	O
intensity	O
S	O
in	O
a	O
pixel	O
depends	O
on	O
the	O
tissue	O
properties	O
T1	B-Algorithm
,	O
T2	B-Algorithm
and	O
PD	O
of	O
the	O
corresponding	O
voxel	B-Algorithm
,	O
as	O
well	O
as	O
the	O
echo	O
time	O
TE	O
and	O
repetition	O
time	O
TR	O
.	O
</s>
<s>
If	O
the	O
acquisition	O
simulated	O
has	O
the	O
echo	O
in	O
the	O
middle	O
of	O
ETL	O
used	O
for	O
central	O
k-space	B-Algorithm
then	O
.	O
</s>
<s>
The	O
scanner	O
parameters	O
TE	O
and	O
TR	O
are	O
the	O
same	O
over	O
the	O
entire	O
slice/volume	O
that	O
is	O
being	O
synthesized	O
but	O
the	O
parameters	O
T1	B-Algorithm
,	O
T2	B-Algorithm
,	O
PD	O
and	O
the	O
resulting	O
signal	O
S	O
are	O
different	O
for	O
different	O
voxels	B-Algorithm
.	O
</s>
<s>
The	O
parameters	O
T1	B-Algorithm
,	O
T2	B-Algorithm
,	O
and	O
PD	O
correspond	O
to	O
physical	O
properties	O
of	O
the	O
tissue	O
within	O
the	O
voxel	B-Algorithm
.	O
</s>
<s>
For	O
IR	O
and	O
DIR	O
the	O
signal	O
may	O
be	O
negative	O
in	O
some	O
voxels	B-Algorithm
.	O
</s>
<s>
In	O
a	O
real	O
MRI	B-Algorithm
scanner	O
the	O
signal	O
is	O
complex	O
and	O
due	O
to	O
off-resonance	O
effects	O
and	O
other	O
scanner	O
imperfections	O
the	O
phase	O
of	O
the	O
complex	O
value	O
may	O
vary	O
between	O
different	O
voxels	B-Algorithm
,	O
this	O
leads	O
to	O
it	O
being	O
difficult	O
to	O
distinguish	O
between	O
a	O
positive	O
and	O
negative	O
signal	O
.	O
</s>
<s>
Post	O
processing	O
software	O
for	O
Synthetic	B-Algorithm
MRI	I-Algorithm
is	O
available	O
in	O
the	O
commercial	O
product	O
SyMRI	O
from	O
SyntheticMR	O
AB	O
which	O
is	O
included	O
as	O
an	O
option	O
called	O
MAGiC	O
on	O
the	O
MR	O
console	O
for	O
GE	O
's	O
SIGNA	O
Pioneer	O
3T	O
MRI	B-Algorithm
scanner	O
.	O
</s>
<s>
Since	O
2017	O
,	O
synthetic	B-Algorithm
MRI	I-Algorithm
is	O
also	O
available	O
in	O
Siemens	O
machines	O
.	O
</s>
<s>
Olea	O
Medical	O
offers	O
a	O
product	O
similar	O
to	O
Synthetic	B-Algorithm
MRI	I-Algorithm
named	O
Olea	O
Nova+	O
.	O
</s>
<s>
It	O
offers	O
a	O
method	O
for	O
automatically	O
computing	O
conventional	O
images	O
from	O
a	O
standard	O
protocol	O
:	O
T1	B-Algorithm
and	O
T2	B-Algorithm
mapping	O
.	O
</s>
<s>
Users	O
are	O
able	O
to	O
create	O
any	O
image	O
contrast-weighed	O
in	O
T1	B-Algorithm
,	O
T2	B-Algorithm
(	O
...	O
)	O
or	O
maps	O
combining	O
various	O
TE	O
,	O
TR	O
,	O
TI	O
.	O
</s>
