<s>
Percutaneous	B-Algorithm
transhepatic	I-Algorithm
cholangiography	I-Algorithm
,	O
percutaneous	O
hepatic	O
cholangiogram	O
(	O
PTHC	B-Algorithm
)	O
is	O
a	O
radiological	O
technique	O
used	O
to	O
visualize	O
the	O
anatomy	O
of	O
the	O
biliary	O
tract	O
.	O
</s>
<s>
A	O
contrast	B-Algorithm
medium	I-Algorithm
is	O
injected	O
into	O
a	O
bile	O
duct	O
in	O
the	O
liver	O
,	O
after	O
which	O
X-rays	B-Library
are	O
taken	O
.	O
</s>
<s>
It	O
allows	O
access	O
to	O
the	O
biliary	O
tree	O
in	O
cases	O
where	O
endoscopic	B-Algorithm
retrograde	I-Algorithm
cholangiopancreatography	I-Algorithm
has	O
been	O
unsuccessful	O
.	O
</s>
<s>
PTHC	B-Algorithm
is	O
frequently	O
performed	O
guide	O
therapy	O
of	O
the	O
biliary	O
system	O
.	O
</s>
<s>
PTHC	B-Algorithm
is	O
also	O
used	O
in	O
the	O
drainage	O
of	O
unruptured	O
or	O
uncomplicated	O
hydatid	O
cysts	O
.	O
</s>
<s>
Rarely	O
,	O
PTHC	B-Algorithm
is	O
used	O
in	O
the	O
drainage	O
of	O
ruptured	O
hydatid	O
cysts	O
.	O
</s>
<s>
Low	O
osmolar	O
contrast	B-Algorithm
medium	I-Algorithm
is	O
used	O
in	O
this	O
procedure	O
with	O
concentration	O
of	O
150	O
mg/ml	O
with	O
20	O
to	O
60	O
ml	O
volume	O
.	O
</s>
<s>
Excessive	O
contrast	B-Algorithm
media	I-Algorithm
injection	O
into	O
the	O
liver	O
should	O
be	O
avoided	O
.	O
</s>
<s>
When	O
there	O
is	O
excessive	O
injection	O
into	O
the	O
liver	O
,	O
lymphatics	O
within	O
the	O
liver	O
will	O
be	O
opacified	O
with	O
contrast	B-Algorithm
medium	I-Algorithm
.	O
</s>
<s>
Injection	O
of	O
the	O
contrast	B-Algorithm
medium	I-Algorithm
into	O
an	O
artery	O
or	O
vein	O
will	O
cause	O
the	O
contrast	O
to	O
dispersed	O
quickly	O
due	O
to	O
blood	O
flow	O
.	O
</s>
<s>
Percutaneous	B-Algorithm
transhepatic	I-Algorithm
cholangiography	I-Algorithm
may	O
increase	O
the	O
incidence	O
of	O
metastasis	O
,	O
tube	O
dislocation	O
,	O
and	O
bleeding	O
when	O
compared	O
to	O
endoscopic	O
biliary	O
drainage	O
.	O
</s>
<s>
Percutaneous	B-Algorithm
transhepatic	I-Algorithm
biliary	I-Algorithm
drainage	I-Algorithm
(	O
PTBD	O
)	O
is	O
often	O
performed	O
if	O
endoscopic	O
retrograde	O
biliary	O
drainage	O
(	O
ERBD	O
)	O
is	O
unsuccessful	O
for	O
biliary	O
obstructions	O
due	O
to	O
hepatocellular	O
carcinoma	O
.	O
</s>
<s>
This	O
procedure	O
is	O
indicated	O
when	O
endoscopic	B-Algorithm
retrograde	I-Algorithm
cholangiopancreatography	I-Algorithm
(	O
ERCP	B-Algorithm
)	O
,	O
papillotomy	O
(	O
cutting	O
through	O
major	O
duodenal	O
papilla	O
to	O
relieve	O
stenosis	O
)	O
or	O
stone	O
removal	O
are	O
unsuccessful	O
.	O
</s>
<s>
Either	O
high	O
osmolar	O
contrast	B-Algorithm
medium	I-Algorithm
or	O
low	O
osmolar	O
contrast	B-Algorithm
medium	I-Algorithm
can	O
be	O
used	O
(	O
with	O
concentration	O
of	O
150	O
mg/ml	O
)	O
.	O
</s>
<s>
Low	O
density	O
contrast	B-Algorithm
medium	I-Algorithm
is	O
used	O
to	O
prevent	O
obscuring	O
of	O
the	O
calculus	O
.	O
</s>
<s>
PTHC	B-Algorithm
is	O
performed	O
if	O
biliary	O
drainage	O
catheter	O
is	O
not	O
in-situ	O
.	O
</s>
<s>
Post-operative	O
T-tube	O
cholangiography	O
is	O
performed	O
on	O
the	O
10th	O
day	O
post	O
operation	O
where	O
either	O
high	O
osmolar	O
or	O
low	O
osmolar	O
contrast	B-Algorithm
media	I-Algorithm
with	O
concentration	O
of	O
150	O
mg/ml	O
with	O
volume	O
of	O
20	O
to	O
30	O
ml	O
is	O
injected	O
through	O
the	O
T-tube	O
to	O
determine	O
if	O
there	O
is	O
any	O
leak	O
from	O
the	O
biliary	O
tract	O
or	O
remaining	O
stones	O
within	O
the	O
biliary	O
system	O
.	O
</s>
