<s>
Coronary	B-Algorithm
CT	I-Algorithm
angiography	I-Algorithm
(	O
CTA	O
or	O
CCTA	O
)	O
is	O
the	O
use	O
of	O
computed	O
tomography	O
(	O
CT	O
)	O
angiography	O
to	O
assess	O
the	O
coronary	O
arteries	O
of	O
the	O
heart	O
.	O
</s>
<s>
The	O
patient	O
receives	O
an	O
intravenous	O
injection	O
of	O
radiocontrast	B-Application
and	O
then	O
the	O
heart	O
is	O
scanned	O
using	O
a	O
high	O
speed	O
CT	O
scanner	O
,	O
allowing	O
physicians	O
to	O
assess	O
the	O
extent	O
of	O
occlusion	O
in	O
the	O
coronary	O
arteries	O
,	O
usually	O
in	O
order	O
to	O
diagnose	O
coronary	O
artery	O
disease	O
.	O
</s>
<s>
CTA	O
is	O
superior	O
to	O
coronary	B-Algorithm
CT	I-Algorithm
calcium	I-Algorithm
scan	I-Algorithm
in	O
determining	O
the	O
risk	O
of	O
Major	O
Adverse	O
Cardiac	O
Events	O
(	O
MACE	O
)	O
.	O
</s>
<s>
Both	O
coronary	B-Algorithm
CT	I-Algorithm
angiography	I-Algorithm
and	O
invasive	O
angiography	O
via	O
cardiac	O
catheterization	O
yield	O
similar	O
diagnostic	O
accuracy	O
when	O
both	O
are	O
being	O
compared	O
to	O
a	O
third	O
reference	O
standard	O
such	O
as	O
intravascular	O
ultrasound	O
or	O
fractional	O
flow	O
reserve	O
.	O
</s>
<s>
This	O
can	O
result	O
in	O
a	O
significant	O
decrease	O
in	O
radiation	O
exposure	O
,	O
at	O
the	O
risk	O
of	O
compromising	O
image	O
quality	O
if	O
there	O
is	O
any	O
arrhythmia	B-Application
during	O
the	O
acquisition	O
.	O
</s>
<s>
Pregnancy	O
is	O
considered	O
a	O
relative	O
contraindication	O
,	O
similarly	O
to	O
many	O
forms	O
of	O
medical	B-Algorithm
imaging	I-Algorithm
in	I-Algorithm
pregnancy	I-Algorithm
.	O
</s>
<s>
The	O
potential	O
harms	O
to	O
a	O
fetus	O
include	O
the	O
application	O
of	O
X-rays	O
in	O
addition	O
to	O
radiocontrast	B-Application
.	O
</s>
<s>
Cardiac	B-Application
arrhythmias	I-Application
,	O
coronary	O
artery	O
stents	O
and	O
tachycardia	B-Application
may	O
result	O
in	O
a	O
reduced	O
image	O
quality	O
.	O
</s>
<s>
Images	O
with	O
even	O
higher	O
temporal	B-General_Concept
resolution	I-General_Concept
can	O
be	O
obtained	O
using	O
multi-cycle	O
(	O
also	O
called	O
multi-segmental	O
)	O
image	O
reconstruction	O
.	O
</s>
<s>
The	O
advantage	O
of	O
this	O
method	O
is	O
that	O
each	O
image	O
segment	O
is	O
acquired	O
in	O
less	O
time	O
as	O
compared	O
to	O
acquiring	O
the	O
entire	O
heart	O
in	O
one	O
heart	O
cycle	O
,	O
thus	O
improving	O
temporal	B-General_Concept
resolution	I-General_Concept
.	O
</s>
<s>
Dual	O
Source	O
CT	O
scanners	O
,	O
introduced	O
in	O
2005	O
,	O
allow	O
higher	O
temporal	B-General_Concept
resolution	I-General_Concept
by	O
acquiring	O
a	O
full	O
CT	O
slice	O
in	O
only	O
half	O
a	O
rotation	O
,	O
thus	O
reducing	O
motion	O
blurring	O
at	O
high	B-Application
heart	I-Application
rates	I-Application
and	O
potentially	O
allowing	O
for	O
shorter	O
breath-hold	O
time	O
.	O
</s>
