<s>
Specifically	O
,	O
through	O
the	O
injection	O
of	O
a	O
liquid	O
radiocontrast	B-Application
agent	I-Application
and	O
illumination	O
with	O
X-rays	B-Library
,	O
</s>
<s>
angiocardiography	B-Algorithm
allows	O
the	O
recognition	O
of	O
occlusion	O
,	O
stenosis	O
,	O
restenosis	O
,	O
thrombosis	O
or	O
aneurysmal	O
enlargement	O
of	O
the	O
coronary	O
artery	O
lumens	O
;	O
heart	O
chamber	O
size	O
;	O
heart	O
muscle	O
contraction	O
performance	O
;	O
and	O
some	O
aspects	O
of	O
heart	O
valve	O
function	O
.	O
</s>
<s>
Less	O
frequently	O
,	O
valvular	O
,	O
heart	O
muscle	O
,	O
or	O
arrhythmia	B-Application
issues	O
are	O
the	O
primary	O
focus	O
of	O
the	O
test	O
.	O
</s>
<s>
The	O
technique	O
of	O
angiography	O
itself	O
was	O
first	O
developed	O
in	O
1927	O
by	O
the	O
Portuguese	O
physician	O
Egas	O
Moniz	O
at	O
the	O
University	O
of	O
Lisbon	O
for	O
cerebral	O
angiography	O
,	O
the	O
viewing	O
of	O
brain	O
vasculature	O
by	O
X-ray	B-Library
radiation	O
with	O
the	O
aid	O
of	O
a	O
contrast	O
medium	O
introduced	O
by	O
catheter	O
.	O
</s>
<s>
He	O
took	O
an	O
x-ray	B-Library
to	O
prove	O
his	O
success	O
and	O
published	O
it	O
on	O
November	O
5	O
,	O
1929	O
,	O
with	O
the	O
title	O
"	O
Über	O
die	O
Sondierung	O
des	O
rechten	O
Herzens	O
"	O
(	O
About	O
probing	O
of	O
the	O
right	O
heart	O
)	O
.	O
</s>
<s>
In	O
1960	O
F	O
.	O
Mason	O
Sones	O
,	O
a	O
pediatric	O
cardiologist	O
at	O
the	O
Cleveland	O
Clinic	O
,	O
accidentally	O
injected	O
radiocontrast	B-Application
in	O
a	O
coronary	O
artery	O
instead	O
of	O
the	O
left	O
ventricle	O
.	O
</s>
<s>
Death	O
,	O
myocardial	O
infarction	O
,	O
stroke	O
,	O
serious	O
ventricular	O
arrhythmia	B-Application
,	O
and	O
major	O
vascular	O
complications	O
each	O
occur	O
in	O
less	O
than	O
1%	O
of	O
patients	O
undergoing	O
catheterization	O
.	O
</s>
<s>
With	O
current	O
designs	O
,	O
the	O
patient	O
must	O
lie	O
relatively	O
flat	O
on	O
a	O
narrow	O
,	O
minimally	O
padded	O
,	O
radiolucent	O
(	O
transparent	O
to	O
X-ray	B-Library
)	O
table	O
.	O
</s>
<s>
The	O
X-ray	B-Library
source	O
and	O
imaging	O
camera	O
equipment	O
are	O
on	O
opposite	O
sides	O
of	O
the	O
patient	O
's	O
chest	O
and	O
freely	O
move	O
,	O
under	O
motorized	O
control	O
,	O
around	O
the	O
patient	O
's	O
chest	O
so	O
images	O
can	O
be	O
taken	O
quickly	O
from	O
multiple	O
angles	O
.	O
</s>
<s>
More	O
advanced	O
equipment	O
,	O
termed	O
a	O
bi-plane	O
cath	O
lab	O
,	O
uses	O
two	O
sets	O
of	O
X-ray	B-Library
source	O
and	O
imaging	O
cameras	O
,	O
each	O
free	O
to	O
move	O
independently	O
,	O
which	O
allows	O
two	O
sets	O
of	O
images	O
to	O
be	O
taken	O
with	O
each	O
injection	O
of	O
radiocontrast	B-Application
agent	I-Application
.	O
</s>
<s>
During	O
coronary	O
catheterization	O
(	O
often	O
referred	O
to	O
as	O
a	O
cath	O
by	O
physicians	O
)	O
,	O
blood	O
pressures	O
are	O
recorded	O
and	O
fluoroscopy	O
(	O
X-ray	B-Library
motion	O
picture	O
)	O
shadow-grams	O
of	O
the	O
blood	O
inside	O
the	O
coronary	O
arteries	O
are	O
recorded	O
.	O
</s>
<s>
In	O
order	O
to	O
create	O
the	O
X-ray	B-Library
pictures	O
,	O
a	O
physician	O
guides	O
a	O
small	O
tube-like	O
device	O
called	O
a	O
catheter	O
,	O
typically	O
~	O
2.0mm	O
(	O
6-French	O
)	O
in	O
diameter	O
,	O
through	O
the	O
large	O
arteries	O
of	O
the	O
body	O
until	O
the	O
tip	O
is	O
just	O
within	O
the	O
opening	O
of	O
one	O
of	O
the	O
coronary	O
arteries	O
.	O
</s>
<s>
The	O
catheter	O
is	O
itself	O
designed	O
to	O
be	O
radiodense	O
for	O
visibility	O
and	O
it	O
allows	O
a	O
clear	O
,	O
watery	O
,	O
blood	O
compatible	O
radiocontrast	B-Application
agent	I-Application
,	O
commonly	O
called	O
an	O
X-ray	B-Library
dye	O
,	O
to	O
be	O
selectively	O
injected	O
and	O
mixed	O
with	O
the	O
blood	O
flowing	O
within	O
the	O
artery	O
.	O
</s>
<s>
Typically	O
3	O
–	O
8	O
cc	O
of	O
the	O
radiocontrast	B-Application
agent	I-Application
is	O
injected	O
for	O
each	O
image	O
to	O
make	O
the	O
blood	O
flow	O
visible	O
for	O
about	O
3	O
–	O
5	O
seconds	O
as	O
the	O
radiocontrast	B-Application
agent	I-Application
is	O
rapidly	O
washed	O
away	O
into	O
the	O
coronary	O
capillaries	O
and	O
then	O
coronary	O
veins	O
.	O
</s>
<s>
Without	O
the	O
X-ray	B-Library
dye	O
injection	O
,	O
the	O
blood	O
and	O
surrounding	O
heart	O
tissues	O
appear	O
,	O
on	O
X-ray	B-Library
,	O
as	O
only	O
a	O
mildly-shape-changing	O
,	O
otherwise	O
uniform	O
water	O
density	O
mass	O
;	O
no	O
details	O
of	O
the	O
blood	O
and	O
internal	O
organ	O
structure	O
are	O
discernible	O
.	O
</s>
<s>
The	O
radiocontrast	B-Application
within	O
the	O
blood	O
allows	O
visualization	O
of	O
the	O
blood	O
flow	O
within	O
the	O
arteries	O
or	O
heart	O
chambers	O
,	O
depending	O
on	O
where	O
it	O
is	O
injected	O
.	O
</s>
<s>
If	O
atheroma	O
,	O
or	O
clots	O
,	O
are	O
protruding	O
into	O
the	O
lumen	O
,	O
producing	O
narrowing	O
,	O
the	O
narrowing	O
may	O
be	O
seen	O
instead	O
as	O
increased	O
haziness	O
within	O
the	O
X-ray	B-Library
shadow	O
images	O
of	O
the	O
blood/dye	O
column	O
within	O
that	O
portion	O
of	O
the	O
artery	O
;	O
this	O
is	O
as	O
compared	O
to	O
adjacent	O
,	O
presumed	O
healthier	O
,	O
less	O
stenotic	O
areas	O
.	O
</s>
<s>
For	O
guidance	O
regarding	O
catheter	O
positions	O
during	O
the	O
examination	O
,	O
the	O
physician	O
mostly	O
relies	O
on	O
detailed	O
knowledge	O
of	O
internal	O
anatomy	O
,	O
guide	O
wire	O
and	O
catheter	O
behavior	O
and	O
intermittently	O
,	O
briefly	O
uses	O
fluoroscopy	O
and	O
a	O
low	O
X-ray	B-Library
dose	O
to	O
visualize	O
when	O
needed	O
.	O
</s>
<s>
When	O
the	O
physician	O
is	O
ready	O
to	O
record	O
diagnostic	O
views	O
,	O
which	O
are	O
saved	O
and	O
can	O
be	O
more	O
carefully	O
scrutinized	O
later	O
,	O
he	O
activates	O
the	O
equipment	O
to	O
apply	O
a	O
significantly	O
higher	O
X-ray	B-Library
dose	O
,	O
termed	O
cine	O
,	O
in	O
order	O
to	O
create	O
better	O
quality	O
motion	O
picture	O
images	O
,	O
having	O
sharper	O
radiodensity	O
contrast	O
,	O
typically	O
at	O
30	O
frames	O
per	O
second	O
.	O
</s>
<s>
The	O
physician	O
controls	O
both	O
the	O
contrast	O
injection	O
,	O
fluoroscopy	O
and	O
cine	O
application	O
timing	O
so	O
as	O
to	O
minimize	O
the	O
total	O
amount	O
of	O
radiocontrast	B-Application
injected	O
and	O
times	O
the	O
X-ray	B-Library
to	O
the	O
injection	O
so	O
as	O
to	O
minimize	O
the	O
total	O
amount	O
of	O
X-ray	B-Library
used	O
.	O
</s>
<s>
Doses	O
of	O
radiocontrast	B-Application
agents	I-Application
and	O
X-ray	B-Library
exposure	O
times	O
are	O
routinely	O
recorded	O
in	O
an	O
effort	O
to	O
maximize	O
safety	O
.	O
</s>
<s>
Angiocardiography	B-Algorithm
can	O
be	O
used	O
to	O
detect	O
and	O
diagnose	O
congenital	O
defects	O
in	O
the	O
heart	O
and	O
adjacent	O
vessels	O
.	O
</s>
<s>
In	O
this	O
context	O
,	O
the	O
use	O
of	O
angiocardiography	B-Algorithm
has	O
declined	O
with	O
the	O
introduction	O
of	O
echocardiography	B-Application
.	O
</s>
<s>
However	O
,	O
angiocardiography	B-Algorithm
is	O
still	O
in	O
use	O
for	O
selected	O
cases	O
as	O
it	O
provides	O
a	O
higher	O
level	O
of	O
anatomical	O
detail	O
than	O
echocardiography	B-Application
.	O
</s>
<s>
By	O
injecting	O
radiocontrast	B-Application
agent	I-Application
through	O
a	O
tiny	O
passage	O
extending	O
down	O
the	O
balloon	O
catheter	O
and	O
into	O
the	O
balloon	O
,	O
the	O
balloon	O
is	O
progressively	O
expanded	O
.	O
</s>
<s>
The	O
radiocontrast	B-Application
filled	O
balloon	O
is	O
watched	O
under	O
fluoroscopy	O
(	O
it	O
typically	O
assumes	O
a	O
"	O
dog	O
bone	O
"	O
shape	O
imposed	O
on	O
the	O
outside	O
of	O
the	O
balloon	O
by	O
the	O
stenosis	O
as	O
the	O
balloon	O
is	O
expanded	O
)	O
,	O
as	O
it	O
opens	O
.	O
</s>
<s>
If	O
over-inflated	O
,	O
the	O
balloon	O
material	O
simply	O
tears	O
and	O
allows	O
the	O
inflating	O
radiocontrast	B-Application
agent	I-Application
to	O
simply	O
escape	O
into	O
the	O
blood	O
.	O
</s>
<s>
Imaging	O
in	O
coronary	O
angiograms	O
is	O
performed	O
via	O
fluoroscopy	O
using	O
X-rays	B-Library
,	O
which	O
pose	O
a	O
potential	O
for	O
increasing	O
the	O
patient	O
's	O
risk	O
of	O
radiation-induced	O
cancer	O
.	O
</s>
<s>
Overall	O
,	O
patient	O
exposure	O
can	O
range	O
from	O
2	O
millisieverts	O
(	O
equivalent	O
of	O
about	O
20	O
chest	O
x-ray	B-Library
plates	O
)	O
to	O
20	O
millisieverts	O
.	O
</s>
