<s>
Renal	B-Algorithm
ultrasonography	I-Algorithm
(	O
Renal	O
US	O
)	O
is	O
the	O
examination	O
of	O
one	O
or	O
both	O
kidneys	O
using	O
medical	B-Application
ultrasound	I-Application
.	O
</s>
<s>
Renal	B-Algorithm
ultrasound	I-Algorithm
(	O
US	O
)	O
is	O
a	O
common	O
examination	O
,	O
which	O
has	O
been	O
performed	O
for	O
decades	O
.	O
</s>
<s>
Furthermore	O
,	O
novel	O
applications	O
in	O
renal	O
US	O
have	O
been	O
introduced	O
with	O
contrast-enhanced	O
ultrasound	O
(	O
CEUS	O
)	O
,	O
elastography	B-Algorithm
and	O
fusion	O
imaging	O
.	O
</s>
<s>
Doppler	B-Algorithm
ultrasonography	I-Algorithm
of	O
the	O
kidney	O
is	O
widely	O
used	O
,	O
and	O
the	O
vessels	O
are	O
easily	O
depicted	O
by	O
the	O
color	B-Algorithm
Doppler	I-Algorithm
technique	O
in	O
order	O
to	O
evaluate	O
perfusion	O
.	O
</s>
<s>
The	O
complex	O
cyst	O
can	O
be	O
further	O
evaluated	O
with	O
Doppler	B-Algorithm
US	I-Algorithm
,	O
and	O
for	O
Bosniak	O
classification	O
and	O
follow-up	O
of	O
complex	O
cysts	O
,	O
either	O
contrast-enhanced	O
ultrasound	O
(	O
CEUS	O
)	O
or	O
contrast	O
CT	O
is	O
used	O
(	O
Figure	O
6	O
)	O
.	O
</s>
<s>
Nevertheless	O
,	O
hemorrhagic	O
cysts	O
can	O
resemble	O
RCC	O
on	O
CT	O
,	O
but	O
they	O
are	O
easily	O
distinguished	O
with	O
Doppler	B-Algorithm
ultrasonography	I-Algorithm
.	O
</s>
<s>
In	O
RCCs	O
,	O
Doppler	B-Algorithm
US	I-Algorithm
often	O
shows	O
vessels	O
with	O
high	O
velocities	O
caused	O
by	O
neovascularization	O
and	O
arteriovenous	O
shunting	O
.	O
</s>
<s>
Some	O
RCCs	O
are	O
hypovascular	O
and	O
not	O
distinguishable	O
with	O
Doppler	B-Algorithm
US	I-Algorithm
.	O
</s>
<s>
Therefore	O
,	O
renal	O
tumors	O
without	O
a	O
Doppler	O
signal	O
,	O
which	O
are	O
not	O
obvious	O
simple	O
cysts	O
on	O
US	O
and	O
CT	O
,	O
should	O
be	O
further	O
investigated	O
with	O
CEUS	O
,	O
as	O
CEUS	O
is	O
more	O
sensitive	O
than	O
both	O
Doppler	B-Algorithm
US	I-Algorithm
and	O
CT	O
for	O
the	O
detection	O
of	O
hypovascular	O
tumors	O
.	O
</s>
<s>
Additional	O
twinkling	O
artifacts	O
below	O
the	O
stone	O
can	O
often	O
be	O
seen	O
using	O
Doppler	B-Algorithm
US	I-Algorithm
.	O
</s>
<s>
An	O
exam	O
of	O
the	O
ureteric	O
orifices	O
and	O
the	O
excretion	O
of	O
urine	O
to	O
the	O
bladder	O
can	O
be	O
performed	O
by	O
inspecting	O
the	O
ureteric	O
jets	O
in	O
the	O
bladder	O
with	O
color	B-Algorithm
Doppler	I-Algorithm
US	O
.	O
</s>
<s>
Sonography	B-Application
is	O
the	O
modality	O
of	O
choice	O
for	O
guidance	O
when	O
performing	O
intervention	O
in	O
the	O
kidney	O
,	O
whether	O
it	O
is	O
kidney	O
biopsy	O
,	O
percutaneous	O
nephrostomy	O
or	O
abscess	O
drainage	O
.	O
</s>
<s>
Contrast-enhanced	O
ultrasound	O
(	O
CEUS	O
)	O
can	O
evaluate	O
microvasculature	O
,	O
which	O
color	B-Algorithm
Doppler	I-Algorithm
US	O
is	O
unable	O
to	O
detect	O
.	O
</s>
<s>
Elastography	B-Algorithm
is	O
a	O
US	O
method	O
to	O
visualize	O
the	O
elasticity	O
of	O
tissue	O
.	O
</s>
<s>
Preliminary	O
reports	O
on	O
US	O
elastography	B-Algorithm
used	O
on	O
transplanted	O
kidneys	O
to	O
evaluate	O
cortical	O
fibrosis	O
have	O
been	O
published	O
showing	O
promising	O
results	O
(	O
Figure	O
32	O
)	O
.	O
</s>
