<s>
Cardiac	B-Algorithm
imaging	I-Algorithm
refers	O
to	O
minimally	O
invasive	O
imaging	O
of	O
the	O
heart	O
using	O
ultrasound	B-Application
,	O
magnetic	O
resonance	O
imaging	O
(	O
MRI	O
)	O
,	O
computed	O
tomography	O
(	O
CT	O
)	O
,	O
or	O
nuclear	O
medicine	O
(	O
NM	O
)	O
imaging	O
with	O
PET	B-Application
or	O
SPECT	O
.	O
</s>
<s>
These	O
cardiac	O
techniques	O
are	O
otherwise	O
referred	O
to	O
as	O
echocardiography	B-Application
,	O
Cardiac	B-Algorithm
MRI	I-Algorithm
,	O
Cardiac	O
CT	O
,	O
Cardiac	B-Algorithm
PET	I-Algorithm
and	O
Cardiac	O
SPECT	O
including	O
myocardial	O
perfusion	O
imaging	O
.	O
</s>
<s>
A	O
physician	O
may	O
recommend	O
cardiac	B-Algorithm
imaging	I-Algorithm
to	O
support	O
a	O
diagnosis	O
of	O
a	O
heart	O
condition	O
.	O
</s>
<s>
Medical	O
specialty	O
professional	O
organizations	O
discourage	O
the	O
use	O
of	O
routine	O
cardiac	B-Algorithm
imaging	I-Algorithm
during	O
pre-operative	O
assessment	O
for	O
patients	O
about	O
to	O
undergo	O
low	O
or	O
mid-risk	O
non-cardiac	O
surgery	O
because	O
the	O
procedure	O
carries	O
risks	O
and	O
is	O
unlikely	O
to	O
result	O
in	O
the	O
change	O
of	O
a	O
patient	O
's	O
management	O
.	O
</s>
<s>
Stress	O
cardiac	B-Algorithm
imaging	I-Algorithm
is	O
discouraged	O
in	O
the	O
evaluation	O
of	O
patients	O
without	O
cardiac	O
symptoms	O
or	O
in	O
routine	O
follow-ups	O
.	O
</s>
<s>
Echocardiography	B-Application
is	O
regularly	O
utilized	O
to	O
diagnose	O
,	O
manage	O
,	O
and	O
monitor	O
patients	O
with	O
suspected	O
or	O
established	O
heart	O
ailments	O
,	O
making	O
it	O
a	O
highly	O
prevalent	O
diagnostic	O
imaging	O
technique	O
in	O
cardiology	O
due	O
to	O
its	O
speed	O
and	O
efficiency	O
.	O
</s>
<s>
Transthoracic	B-Application
echocardiography	I-Application
(	O
TTE	O
)	O
uses	O
ultrasonic	B-Application
waves	O
for	O
continuous	O
heart	O
chamber	O
and	O
blood	O
movement	O
visualization	O
.	O
</s>
<s>
Stress	O
echocardiography	B-Application
is	O
used	O
to	O
diagnose	O
coronary	O
artery	O
disease	O
and	O
assess	O
myocardial	O
viability	O
.	O
</s>
<s>
Transesophageal	O
echocardiography	B-Application
is	O
an	O
invasive	O
procedure	O
that	O
involves	O
inserting	O
a	O
flexible	O
probe	O
with	O
an	O
ultrasound	B-Application
transducer	O
into	O
the	O
esophagus	O
,	O
providing	O
closer	O
access	O
to	O
the	O
heart	O
and	O
surrounding	O
structures	O
.	O
</s>
<s>
Transesophageal	O
echocardiography	B-Application
creates	O
clearer	O
images	O
of	O
the	O
heart	O
and	O
surrounding	O
blood	O
vessels	O
than	O
traditional	O
transthoracic	B-Application
echocardiography	I-Application
(	O
TTE	O
)	O
.	O
</s>
<s>
TEE	O
is	O
also	O
limited	O
by	O
available	O
anatomy	O
and	O
may	O
require	O
a	O
second	O
procedure	O
,	O
such	O
as	O
esophagogastroduodenoscopy	B-Application
,	O
to	O
visualize	O
the	O
anatomy	O
for	O
safety	O
.	O
</s>
<s>
The	O
technique	O
acquires	O
a	O
volumetric	O
data	O
set	O
and	O
displays	O
it	O
in	O
custom	O
orientations	O
,	O
allowing	O
for	O
greater	O
depth	O
and	O
understanding	O
of	O
heart	O
structures	O
compared	O
to	O
2D	O
echocardiography	B-Application
.	O
</s>
<s>
The	O
introduction	O
of	O
ultrasound	B-Application
contrast	O
agents	O
for	O
contrast	O
echocardiography	B-Application
has	O
significantly	O
improved	O
the	O
usefulness	O
of	O
echocardiography	B-Application
in	O
diagnosing	O
and	O
assessing	O
coronary	O
artery	O
disease	O
.	O
</s>
<s>
Ultrasound	B-Application
contrast	O
is	O
used	O
for	O
assessing	O
left	O
ventricular	O
ejection	O
fraction	O
at	O
rest	O
and	O
during	O
stress	O
echocardiography	B-Application
.	O
</s>
<s>
Contrast	O
echocardiography	B-Application
can	O
simultaneously	O
assess	O
regional	O
myocardial	O
function	O
and	O
perfusion	O
,	O
allowing	O
for	O
the	O
non-invasive	O
diagnosis	O
of	O
coronary	O
artery	O
disease	O
.	O
</s>
<s>
Contrast	O
echocardiography	B-Application
requires	O
intravenous	O
administration	O
of	O
an	O
ultrasound	B-Application
contrast	O
agent	O
during	O
contrast	O
specific	O
ultrasound	B-Application
imaging	O
.	O
</s>
<s>
Cardiovascular	B-Algorithm
magnetic	I-Algorithm
resonance	I-Algorithm
(	O
MR	O
)	O
technology	O
is	O
able	O
to	O
measure	O
the	O
size	O
,	O
shape	O
,	O
function	O
,	O
and	O
tissue	O
characteristics	O
of	O
the	O
heart	O
in	O
a	O
single	O
session	O
.	O
</s>
<s>
It	O
is	O
more	O
reproducible	O
than	O
echocardiography	B-Application
with	O
less	O
inter-observer	O
variability	O
,	O
allowing	O
for	O
more	O
precise	O
reference	O
ranges	O
to	O
better	O
distinguish	O
health	O
from	O
disease	O
.	O
</s>
<s>
Additional	O
benefits	O
from	O
cardiac	B-Algorithm
MRI	I-Algorithm
include	O
the	O
ability	O
to	O
detect	O
scar	O
within	O
the	O
heart	O
using	O
late	O
gadolinium	O
enhancement	O
,	O
and	O
identify	O
other	O
abnormalities	O
of	O
the	O
heart	O
muscle	O
itself	O
such	O
as	O
infiltration	O
with	O
iron	O
or	O
amyloid	O
protein	O
.	O
</s>
<s>
Furthermore	O
,	O
an	O
MRI	O
scan	O
cannot	O
be	O
performed	O
in	O
some	O
people	O
who	O
have	O
metallic	O
implants	O
such	O
as	O
some	O
types	O
of	O
pacemakers	B-Device
,	O
defibrillators	O
,	O
although	O
many	O
modern	O
pacemakers	B-Device
are	O
safe	O
for	O
use	O
within	O
an	O
MRI	O
scanner	O
.	O
</s>
<s>
Recent	O
development	O
in	O
deep	B-Algorithm
learning	I-Algorithm
and	O
convolutional	B-Architecture
neural	I-Architecture
network	I-Architecture
techniques	O
have	O
made	O
it	O
possible	O
to	O
analyze	O
and	O
quantify	O
some	O
aspects	O
of	O
cardiac	B-Algorithm
MRI	I-Algorithm
automatically	O
.	O
</s>
<s>
The	O
use	O
of	O
cardiac	B-Algorithm
MRI	I-Algorithm
is	O
projected	O
to	O
increase	O
through	O
greater	O
availability	O
of	O
scanners	O
and	O
more	O
widespread	O
knowledge	O
about	O
its	O
clinical	O
application	O
.	O
</s>
<s>
Computed	O
tomography	O
angiography	O
(	O
CTA	O
)	O
,	O
an	O
imaging	O
methodology	O
using	O
a	O
ring-shaped	O
machine	O
with	O
an	O
X-ray	B-Library
source	O
spinning	O
around	O
the	O
circular	O
path	O
so	O
as	O
to	O
bathe	O
the	O
inner	O
circle	O
with	O
a	O
uniform	O
and	O
known	O
X-ray	B-Library
density	O
.	O
</s>
<s>
This	O
is	O
achieved	O
through	O
the	O
use	O
of	O
thin	O
slices	O
and	O
high-resolution	O
scanning	O
,	O
as	O
well	O
as	O
the	O
addition	O
of	O
electrocardiogram	B-Application
(	O
ECG	B-Application
)	O
gating	O
or	O
triggering	O
to	O
capture	O
a	O
motion-free	O
image	O
.	O
</s>
<s>
Standard	O
CT	O
scans	O
are	O
acquired	O
in	O
either	O
Axial	O
or	O
Helical	O
modes	O
,	O
while	O
CCT	O
adds	O
the	O
ECG	B-Application
gating	O
dimension	O
to	O
these	O
modes	O
to	O
capture	O
images	O
of	O
the	O
heart	O
.	O
</s>
<s>
These	O
modifications	O
are	O
necessary	O
to	O
obtain	O
the	O
required	O
data	O
from	O
the	O
planar	O
slice	O
images	O
,	O
which	O
are	O
reconstructed	O
from	O
back-projected	O
transmitted	O
data	O
obtained	O
by	O
radial	O
excursion	O
of	O
the	O
X-ray	B-Library
tube	O
and	O
detector	O
.	O
</s>
<s>
A	O
coronary	B-Algorithm
CT	I-Algorithm
calcium	I-Algorithm
scan	I-Algorithm
is	O
a	O
computed	O
tomography	O
(	O
CT	O
)	O
scan	O
of	O
the	O
heart	O
for	O
the	O
assessment	O
of	O
severity	O
of	O
coronary	O
artery	O
disease	O
.	O
</s>
<s>
This	O
severity	O
can	O
be	O
presented	O
as	O
Agatston	B-Algorithm
score	I-Algorithm
or	O
Coronary	B-Algorithm
Artery	I-Algorithm
Calcium	I-Algorithm
(	O
CAC	O
)	O
score	O
.	O
</s>
<s>
A	O
typical	O
coronary	B-Algorithm
CT	I-Algorithm
calcium	I-Algorithm
scan	I-Algorithm
is	O
done	O
without	O
the	O
use	O
of	O
radiocontrast	B-Application
dye	I-Application
,	O
but	O
it	O
can	O
possibly	O
be	O
done	O
from	O
contrast-enhanced	O
images	O
as	O
well	O
,	O
such	O
as	O
in	O
coronary	B-Algorithm
CT	I-Algorithm
angiography	I-Algorithm
.	O
</s>
<s>
Positron	B-Application
emission	I-Application
tomography	I-Application
(	O
PET	B-Application
)	O
is	O
a	O
nuclear	O
medicine	O
imaging	O
methodology	O
that	O
tracks	O
positron	O
emitting	O
radioisotopes	O
.	O
</s>
<s>
PET	B-Application
enables	O
visual	O
image	O
analysis	O
of	O
multiple	O
different	O
metabolic	O
chemical	O
processes	O
and	O
is	O
thus	O
one	O
of	O
the	O
most	O
flexible	O
imaging	O
technologies	O
.	O
</s>
<s>
Appropriate	O
radioisotopes	O
of	O
elements	O
within	O
chemical	O
compounds	O
of	O
the	O
metabolic	O
pathway	O
being	O
examined	O
are	O
used	O
to	O
make	O
the	O
location	O
of	O
the	O
chemical	O
compounds	O
of	O
interest	O
visible	O
in	O
a	O
PET	B-Application
image	O
.	O
</s>
<s>
PET	B-Application
tracers	O
emit	O
positrons	O
,	O
which	O
are	O
nearly	O
identical	O
to	O
negatively	O
charged	O
electrons	O
,	O
but	O
have	O
the	O
opposite	O
charge	O
and	O
are	O
considered	O
antimatter	O
.	O
</s>
<s>
PET	B-Application
scanners	I-Application
detect	O
these	O
gamma	O
rays	O
to	O
produce	O
images	O
showing	O
the	O
location	O
of	O
the	O
positrons	O
and	O
the	O
metabolic	O
processes	O
in	O
the	O
body	O
.	O
</s>
<s>
Most	O
new	O
PET	B-Application
scanners	I-Application
are	O
combined	O
with	O
a	O
CT	O
scanner	O
,	O
a	O
type	O
of	O
X-ray	B-Library
machine	O
.	O
</s>
<s>
A	O
CT	O
scan	O
is	O
typically	O
done	O
first	O
,	O
followed	O
by	O
a	O
PET	B-Application
scan	I-Application
.	O
</s>
<s>
For	O
cardiac	O
scans	O
,	O
combining	O
CT	O
cardiac	O
data	O
with	O
PET	B-Application
metabolic	O
or	O
perfusion	O
data	O
from	O
PET/CT	O
machines	O
may	O
be	O
of	O
clinical	O
value	O
.	O
</s>
<s>
While	O
there	O
are	O
unresolved	O
issues	O
with	O
using	O
a	O
high-speed	O
CT	O
scan	O
for	O
attenuation	O
correction	O
of	O
cardiac	O
images	O
,	O
many	O
new	O
CT	O
scanners	O
are	O
marketed	O
with	O
PET	B-Application
scanners	I-Application
and	O
can	O
be	O
used	O
to	O
measure	O
myocardial	O
thickening	O
,	O
which	O
is	O
a	O
useful	O
adjunct	O
to	O
PET	B-Application
physiological	O
imaging	O
.	O
</s>
<s>
PET/MRI	O
systems	O
combine	O
the	O
capabilities	O
of	O
positron	B-Application
emission	I-Application
tomography	I-Application
(	O
PET	B-Application
)	O
and	O
magnetic	O
resonance	O
imaging	O
(	O
MRI	O
)	O
to	O
provide	O
both	O
functional	O
and	O
morphological	O
information	O
in	O
various	O
clinical	O
applications	O
.	O
</s>
<s>
Cardiac	B-Algorithm
MRI	I-Algorithm
can	O
produce	O
complementary	O
data	O
to	O
increase	O
accuracy	O
and	O
reproducibility	O
to	O
PET	B-Application
scans	I-Application
,	O
especially	O
in	O
systemic	O
diseases	O
,	O
inflammatory	O
processes	O
,	O
assessing	O
risk	O
of	O
atherosclerotic	O
plaque	O
rupture	O
,	O
and	O
stem	O
cell	O
tracking	O
.	O
</s>
<s>
PET/MRI	O
systems	O
come	O
in	O
two	O
types	O
:	O
tandem	O
,	O
in-line	O
systems	O
where	O
two	O
imagers	O
share	O
a	O
patient	O
transport	O
system	O
for	O
sequential	O
acquisitions	O
,	O
and	O
integrated	O
systems	O
where	O
both	O
scanners	O
operate	O
simultaneously	O
.	O
</s>
<s>
PET/MRI	O
is	O
still	O
in	O
its	O
early	O
stages	O
,	O
and	O
more	O
work	O
is	O
needed	O
to	O
establish	O
it	O
as	O
a	O
widespread	O
and	O
cost-effective	O
clinical	O
tool	O
for	O
cardiac	B-Algorithm
imaging	I-Algorithm
.	O
</s>
<s>
Coronary	O
catheterization	O
uses	O
pressure	O
monitoring	O
and	O
blood	O
sampling	O
through	O
a	O
catheter	O
inserted	O
into	O
the	O
heart	O
through	O
blood	O
vessels	O
in	O
the	O
leg	O
or	O
wrist	O
to	O
determine	O
the	O
functioning	O
of	O
the	O
heart	O
,	O
and	O
,	O
following	O
injections	O
of	O
radiocontrast	B-Application
dye	I-Application
,	O
uses	O
X-ray	B-Library
fluoroscopy	O
,	O
typically	O
at	O
30	O
frames	O
per	O
second	O
,	O
to	O
visualize	O
the	O
position	O
and	O
volume	O
of	O
blood	O
within	O
the	O
heart	O
chambers	O
and	O
arteries	O
.	O
</s>
<s>
Intravascular	O
ultrasound	B-Application
,	O
also	O
known	O
as	O
a	O
percutaneous	O
echocardiogram	B-Application
is	O
an	O
imaging	O
methodology	O
using	O
specially	O
designed	O
,	O
long	O
,	O
thin	O
,	O
complex	O
manufactured	O
catheters	O
attached	O
to	O
computerized	O
ultrasound	B-Application
equipment	O
to	O
visualize	O
the	O
lumen	O
and	O
the	O
interior	O
wall	O
of	O
blood	O
vessels	O
.	O
</s>
